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Francois Chollet: François Chollet: Keras, Deep Learning, and the Progress of AI

第2019-09-14期2019-09-14English

嘉宾:Francois Chollet

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§01Transcript · 00:00–09:30

00:00The following is a conversation with Francois Chollet.

00:03He's the creator of Keras, which is an open source deep learning

00:07library that is designed to enable

00:09fast, user-friendly experimentation

00:11with deep neural networks.

00:13It serves as an interface to several deep learning libraries,

00:16most popular of which is TensorFlow.

00:19And it was integrated into the TensorFlow main code

00:22base a while ago.

00:24Meaning, if you want to create, train, and use neural networks,

00:28probably the easiest and most popular option

00:31is to use Keras inside TensorFlow.

00:34Aside from creating an exceptionally useful

00:37and popular library, Francois is also a world-class AI

00:41researcher and software engineer at Google.

00:44And he's definitely an outspoken, if not controversial,

00:48personality in the AI world, especially

00:51in the realm of ideas around the future

00:53of artificial intelligence.

00:55This is the Artificial Intelligence Podcast.

00:58If you enjoy it, subscribe on YouTube,

01:01give us five stars on iTunes, support on Patreon,

01:04or simply connect with me on Twitter at Lex Friedman,

01:07spelled F-R-I-D-M-A-N. And now, here's my conversation

01:12with Francois Chollet.

01:14You're known for not sugarcoating your opinions

01:17and speaking your mind about ideas in AI,

01:19especially on Twitter.

01:21It's one of my favorite Twitter accounts.

01:22So what's one of the more controversial ideas

01:26you've expressed online and gotten some heat for?

01:30How do you pick?

01:33How do I pick?

01:33Yeah, no, I think if you go through the trouble

01:36of maintaining a Twitter account,

01:39you might as well speak your mind.

01:41Otherwise, what's even the point of having a Twitter account?

01:44It's like having a nice car and just leaving it in the garage.

01:48Yeah, so what's one thing for which I got

01:52a lot of pushback?

01:53Perhaps, you know, that time I wrote something

01:56about the idea of intelligence explosion.

02:00And I was questioning the idea

02:04and the reasoning behind this idea.

02:06And I got a lot of pushback on that.

02:09I got a lot of flack for it.

02:11So yeah, so intelligence explosion,

02:13I'm sure you're familiar with the idea,

02:14but it's the idea that if you were to build

02:18general AI problem solving algorithms,

02:22well, the problem of building such an AI,

02:27that itself is a problem that could be solved by your AI.

02:30And maybe it could be solved better than what humans can do.

02:33So your AI could start tweaking its own algorithm,

02:36could start being a better version of itself.

02:39And so on, iteratively, in a recursive fashion.

02:43And so you would end up with an AI

02:47with exponentially increasing intelligence.

02:50That's right.

02:50And I was basically questioning this idea,

02:55first of all, because the notion of intelligence explosion

02:59uses an implicit definition of intelligence

03:02that doesn't sound quite right to me.

03:05It considers intelligence as a property of a brain

03:11that you can consider in isolation,

03:13like the height of a building, for instance.

03:15Right.

03:16But that's not really what intelligence is.

03:19Intelligence emerges from the interaction between a brain,

03:24a body, like embodied intelligence,

03:26and an environment.

03:28And if you're missing one of these pieces,

03:30then you cannot really define intelligence anymore.

03:33So just tweaking a brain to make it smaller and smaller

03:36doesn't actually make any sense to me.

03:39So first of all, you're crushing the dreams of many people.

03:42Right.

03:43So there's a, let's look at like Sam Harris.

03:46Actually, a lot of physicists, Max Tegmark,

03:48people who think the universe is an information processing

03:53system.

03:54Our brain is kind of an information processing system.

03:57So what's the theoretical limit?

04:00It doesn't make sense that there should be some--

04:04it seems naive to think that our own brain is somehow

04:08the limit of the capabilities of this information.

04:11I'm playing devil's advocate here.

04:13This information processing system.

04:15And then if you just scale it, if you're

04:18able to build something that's on par with the brain,

04:21the process that builds it just continues,

04:24and it'll improve exponentially.

04:26So that's the logic that's used, actually,

04:30by almost everybody that is worried

04:33about superhuman intelligence.

04:36Yeah.

04:37So you're trying to make--

04:39so most people who are skeptical of that are kind of like,

04:42this doesn't-- the thought process,

04:44this doesn't feel right.

04:46That's for me as well.

04:47So I'm more like, it doesn't--

04:51the whole thing is shrouded in mystery where you can't really

04:54say anything concrete, but you could

04:56say this doesn't feel right.

04:57This doesn't feel like that's how the brain works.

05:00And you're trying to, with your blog post,

05:02and now making it a little more explicit.

05:05So one idea is that the brain doesn't exist alone.

05:11It exists within the environment.

05:13So you can't exponentially--

05:16you would have to somehow exponentially

05:18improve the environment and the brain together,

05:21almost, in order to create something that's much smarter

05:26in some kind of--

05:28of course, we don't have a definition of intelligence.

05:30That's correct.

05:31That's correct.

05:31I don't think-- if you look at very smart people today,

05:34even humans, not even talking about AIs,

05:37I don't think their brain and the performance of their brain

05:41is the bottleneck to their expressed intelligence,

05:44to their achievements.

05:47You cannot just tweak one part of this system,

05:50like of this brain-body environment system,

05:53and expect the capabilities, like what emerges out

05:56of this system, to just explode exponentially.

06:00Because any time you improve one part

06:04of a system with many interdependencies like this,

06:07there's a new bottleneck that arises.

06:09And I don't think even today, for very smart people,

06:12their brain is not the bottleneck to the sort

06:15of problems they can solve.

06:17In fact, many very, very smart people today,

06:21they're not actually solving any big scientific problems.

06:23They're not Einstein.

06:24They're like Einstein, but the patent clerk days.

06:29Like Einstein became Einstein because this

06:32was a meeting of a genius with a big problem at the right time.

06:39But maybe this meeting could have never happened.

06:42And then Einstein would have just been a patent clerk.

06:45And in fact, many people today are probably

06:48like genius level smart, but you wouldn't know,

06:52because they're not really expressing any of that.

06:54- Wow, that's brilliant.

06:55So we can think of the world, Earth, but also the universe

06:59as just as a space of problems.

07:02So all of these problems and tasks are roaming it,

07:05of various difficulty.

07:06And there's agents, creatures like ourselves

07:10and animals and so on that are also roaming it.

07:13And then you get coupled with a problem

07:16and then you solve it.

07:17But without that coupling, you can't demonstrate

07:20your quote unquote intelligence.

07:22- Exactly, intelligence is the meeting

07:24of great problem solving capabilities

07:27with a great problem.

07:28And if you don't have the problem,

07:30you don't really express an intelligence.

07:32All you're left with is potential intelligence,

07:34like the performance of your brain

07:36or how high your IQ is, which in itself is just a number.

07:41- So you mentioned problem solving capacity.

07:46What do you think of as problem solving capacity?

07:51Can you try to define intelligence?

07:55Like what does it mean to be more or less intelligent?

08:00Is it completely coupled to a particular problem

08:03or is there something a little bit more universal?

08:05- Yeah, I do believe all intelligence

08:07is specialized intelligence.

08:09Even human intelligence has some degree of generality.

08:12Well, all intelligence systems have some degree of generality

08:15but they're always specialized in one category of problems.

08:19So the human intelligence is specialized

08:21in the human experience and that shows at various levels.

08:25That shows in some prior knowledge that's innate

08:30that we have at birth.

08:32Knowledge about things like agents, goal-driven behavior,

08:37visual priors about what makes an object,

08:40priors about time and so on.

08:43That shows also in the way we learn.

08:45For instance, it's very, very easy for us

08:47to pick up language.

08:48It's very, very easy for us to learn certain things

08:52because we are basically hard-coded to learn them.

08:54And we are specialized in solving certain kinds of problem

08:58and we are quite useless when it comes

09:00to other kinds of problems.

09:01For instance, we are not really designed

09:06to handle very long-term problems.

09:08We have no capability of seeing the very long-term.

09:12We don't have very much working memory.

09:16- So how do you think about long-term?

09:20Do you think long-term planning,

09:21are we talking about scale of years, millennia?

09:24What do you mean by long-term we're not very good?

09:28- Well, human intelligence is specialized

09:29in the human experience.

09:30And human experience is very short.

§02Transcript · 09:32–18:54

09:32Like one lifetime is short.

09:34Even within one lifetime, we have a very hard time

09:38envisioning things on a scale of years.

09:41Like it's very difficult to project yourself

09:43at the scale of five years,

09:44at the scale of 10 years and so on.

09:46- Right.

09:47- We can solve only fairly narrowly scoped problems.

09:50So when it comes to solving bigger problems,

09:52larger scale problems,

09:53we are not actually doing it on an individual level.

09:56So it's not actually our brain doing it.

09:59We have this thing called civilization, right?

10:03Which is itself a sort of problem solving system,

10:06a sort of artificial intelligence system, right?

10:10And it's not running on one brain,

10:12it's running on a network of brains.

10:14In fact, it's running on much more

10:15than a network of brains.

10:16It's running on a lot of infrastructure,

10:20like books and computers and the internet

10:23and human institutions and so on.

10:25And that is capable of handling problems

10:30on a much greater scale than any individual human.

10:33If you look at computer science, for instance,

10:37that's an institution that solves problems

10:39and it is superhuman, right?

10:42I had to press on a greater scale,

10:44it can solve much bigger problems

10:46than an individual human could.

10:49And science itself, science as a system,

10:51as an institution is a kind of artificially intelligent

10:55problem solving algorithm that is superhuman.

10:59- Yeah, it's a, at least computer science

11:02is like a theorem prover at a scale of thousands,

11:07maybe hundreds of thousands of human beings.

11:10At that scale, what do you think is an intelligent agent?

11:14So there's us humans at the individual level,

11:18there is millions, maybe billions of bacteria in our skin.

11:23There is, that's at the smaller scale.

11:26You can even go to the particle level

11:29as systems that behave, you can say intelligently

11:33in some ways, and then you can look at Earth

11:36as a single organism, you can look at our galaxy

11:39and even the universe as a single organism.

11:42Do you think, how do you think about scale

11:44and defining intelligent systems?

11:46And we're here at Google, there is millions of devices

11:50doing computation in a distributed way.

11:53How do you think about intelligence versus scale?

11:55- You can always characterize anything as a system.

11:59- Right.

12:00- I think people who talk about things

12:03like intelligence explosion tend to focus on one agent

12:07is basically one brain, like one brain considered

12:10in isolation, like a brain, a jaw that's controlling

12:12a body in a very like top to bottom kind of fashion.

12:16And that body is pursuing goals into an environment.

12:19So it's a very hierarchical view.

12:20You have the brain at the top of the pyramid,

12:22then you have the body just plainly receiving orders

12:26and then the body is manipulating objects

12:27in an environment and so on.

12:28So everything is subordinate to this one thing,

12:32this epicenter, which is the brain.

12:34But in real life, intelligent agents

12:37don't really work like this, right?

12:39There is no strong delimitation between the brain

12:41and the body to start with.

12:43You have to look not just at the brain,

12:45but at the nervous system.

12:46But then the nervous system and the body

12:48are not really two separate entities.

12:50So you have to look at an entire animal as one agent,

12:53but then you start realizing as you observe an animal

12:57over any length of time, that a lot of the intelligence

13:02of an animal is actually externalized.

13:04That's especially true for humans.

13:06A lot of our intelligence is externalized.

13:08When you write down some notes,

13:10that is externalized intelligence.

13:11When you write a computer program,

13:14you are externalizing cognition.

13:16So it's externalized in books, it's externalized

13:18in computers, the internet, in other humans.

13:21It's externalized in language and so on.

13:25So there is no hard delimitation

13:30of what makes an intelligent agent.

13:32It's all about context.

13:33- Okay, but AlphaGo is better at Go

13:38than the best human player.

13:40There's levels of skill here.

13:44So do you think there's such a concept

13:49as intelligence explosion in a specific task?

13:54And then, well, yeah, do you think it's possible

13:58to have a category of tasks on which you do have something

14:02like an exponential growth of ability

14:05to solve that particular problem?

14:07- I think if you consider a specific vertical,

14:10it's probably possible to some extent

14:14I also don't think we have to speculate about it

14:17because we have real world examples

14:21of recursively self-improving intelligent systems.

14:25- Right.

14:26- So for instance, science is a problem solving system,

14:30a knowledge generation system,

14:31like a system that experiences the world in some sense

14:35and then gradually understands it and can act on it.

14:39And that system is superhuman

14:42and it is clearly recursively self-improving

14:45because science feeds into technology.

14:47Technology can be used to build better tools,

14:50better computers, better instrumentation and so on,

14:52which in turn can make science faster, right?

14:56So science is probably the closest thing we have today

15:00to a recursively self-improving superhuman AI.

15:04And you can just observe,

15:06is scientific progress today exploding,

15:10which itself is an interesting question.

15:12And you can use that as a basis to try to understand

15:15what will happen with a superhuman AI

15:17that has science-like behavior.

15:20- Let me linger on it a little bit more.

15:23What is your intuition why an intelligence explosion

15:27is not possible?

15:28Like taking the scientific,

15:30all the scientific revolutions,

15:33why can't we slightly accelerate that process?

15:38- So you can absolutely accelerate

15:41any problem-solving process.

15:43So recursive self-improvement is absolutely a real thing.

15:48But what happens with a recursively self-improving system

15:51is typically not explosion

15:53because no system exists in isolation.

15:56And so tweaking one part of the system

15:58means that suddenly another part of the system

16:00becomes a bottleneck.

16:02And if you look at science, for instance,

16:03which is clearly recursively self-improving,

16:06clearly a problem-solving system,

16:09scientific progress is not actually exploding.

16:12If you look at science,

16:13what you see is the picture of a system

16:16that is consuming an exponentially increasing

16:19amount of resources.

16:20But it's having a linear output

16:23in terms of scientific progress.

16:25And maybe that will seem like a very strong claim.

16:28Many people are actually saying that,

16:31scientific progress is exponential,

16:34but when they're claiming this,

16:36they're actually looking at indicators

16:38of resource consumption by science.

16:43For instance, the number of papers being published,

16:46the number of patents being filed and so on,

16:49which are just completely correlated

16:53with how many people are working on science today.

16:58So it's actually an indicator of resource consumption.

17:00But what you should look at is the output,

17:03is progress in terms of the knowledge that science generates

17:08in terms of the scope and significance

17:10of the problems that we solve.

17:12And some people have actually been trying to measure that.

17:16Like Michael Nielsen, for instance.

17:20He had a very nice paper,

17:21I think that was last year about it.

17:23So his approach to measure scientific progress

17:28was to look at the timeline of scientific discoveries

17:33over the past 100, 150 years.

17:37And for each measured discovery,

17:41ask a panel of experts

17:43to rate the significance of the discovery.

17:46And if the output of science as an institution

17:49were exponential, you would expect

17:51the temporal density of significance

17:56to go up exponentially.

17:58Maybe because there's a faster rate of discoveries,

18:00maybe because the discoveries are increasingly

18:03more important.

18:04And what actually happens if you plot

18:07this temporal density of significance measured in this way,

18:11is that you see very much a flat graph.

18:14You see a flat graph across all disciplines,

18:16across physics, biology, medicine, and so on.

18:19And it actually makes a lot of sense if you think about it,

18:23because think about the progress of physics

18:26110 years ago, right?

18:28It was a time of crazy change.

18:30Think about the progress of technology,

18:31you know, 170 years ago,

18:34when we started having, you know,

18:35replacing horses with cars,

18:37when we started having electricity and so on.

18:40It was a time of incredible change.

18:41And today is also a time of very, very fast change,

18:44but it would be an unfair characterization

18:48to say that today, technology and science

18:50are moving way faster than they did 50 years ago,

18:52100 years ago.

18:54And if you do try to

§03Transcript · 18:58–27:42

18:58rigorously plot the temporal density

19:01of the significance,

19:04yeah, of significance idea,

19:06of significance idea, sorry,

19:07you do see very flat curves.

19:09- That's fascinating.

19:10- And you can check out the paper that Michael Nielsen

19:13had about this idea.

19:16And so the way I interpret it is,

19:20as you make progress,

19:22you know, in a given field

19:24or in a given subfield of science,

19:26it becomes exponentially more difficult

19:28to make further progress.

19:30Like the very first person to work on information theory.

19:35If you enter a new field,

19:36and it's still the very early years,

19:37there's a lot of low hanging fruit you can pick.

19:41- That's right, yeah.

19:42- But the next generation of researchers

19:43is gonna have to dig much harder actually

19:48to make smaller discoveries,

19:50probably larger numbers, smaller discoveries.

19:52And to achieve the same amount of impact,

19:54you're gonna need a much greater headcount.

19:57And that's exactly the picture you're seeing with science,

20:00is that the number of scientists and engineers

20:03is in fact increasing exponentially.

20:06The amount of computational resources

20:08that are available to science

20:10is increasing exponentially and so on.

20:11So the resource consumption of science is exponential,

20:15but the output in terms of progress,

20:18in terms of significance is linear.

20:20And the reason why is because,

20:23and even though science is recursively self-improving,

20:25meaning that scientific progress

20:28turns into technological progress,

20:30which in turn helps science.

20:32If you look at computers, for instance,

20:35are a product of science,

20:37and computers are tremendously useful

20:40in speeding up science.

20:41The internet, same thing.

20:42The internet is a technology that's made possible

20:44by very recent scientific advances.

20:47And itself, because it enables scientists to network,

20:52to communicate, to exchange papers and ideas much faster,

20:55it is a way to speed up scientific progress.

20:57So even though you're looking

20:58at a recursively self-improving system,

21:01it is consuming exponentially more resources

21:04to produce the same amount of problem-solving very much.

21:09- So that's a fascinating way to paint it.

21:11And certainly that holds for the deep learning community.

21:14If you look at the temporal, what did you call it?

21:18The temporal density of significant ideas.

21:21If you look at in deep learning,

21:23I think, I'd have to think about that,

21:26but if you really look at significant ideas

21:29in deep learning, they might even be decreasing.

21:32- So I do believe the per paper significance is decreasing.

21:37But the amount of papers is still today

21:42exponentially increasing.

21:43So I think if you look at an aggregate,

21:45my guess is that you would see a linear progress.

21:48- Linear progress.

21:49- If you were to sum the significance of all papers,

21:53you would see a roughly linear progress.

21:58And in my opinion, it is not a coincidence

22:03that you're seeing linear progress in science

22:05despite exponential resource consumption.

22:07I think the resource consumption

22:10is dynamically adjusting itself to maintain linear progress

22:15because we as a community expect linear progress,

22:18meaning that if we start investing less

22:21and seeing less progress,

22:22it means that suddenly there are some lower hanging fruits

22:25that become available and someone's gonna step up

22:29and pick them.

22:31So it's very much like a market for discoveries and ideas.

22:36- But there's another fundamental part

22:38which you're highlighting,

22:39which is a hypothesis that science,

22:42or like the space of ideas,

22:45any one path you travel down,

22:48it gets exponentially more difficult

22:51to develop new ideas.

22:54And your sense is that's gonna hold

22:57across our mysterious universe.

23:01- Yes, well, exponential progress

23:03triggers exponential friction.

23:05So that if you tweak one part of the system,

23:07suddenly some other part becomes a bottleneck.

23:10For instance, let's say we develop some device

23:14that measures its own acceleration

23:17and then it has some engine

23:18and it outputs even more acceleration

23:20in proportion of its own acceleration

23:22and you drop it somewhere,

23:23it's not gonna reach infinite speed

23:25because it exists in a certain context.

23:27So the air around it is gonna generate friction.

23:31It's gonna block it at some top speed.

23:34And even if you were to consider the broader context

23:37and lift the bottleneck there,

23:39like the bottleneck of friction,

23:42then some other part of the system

23:45would start stepping in

23:46and creating exponential friction,

23:48maybe the speed of light, or whatever.

23:49And this definitely holds true

23:51when you look at the problem-solving algorithm

23:55that is being run by science as an institution,

23:58science as a system.

23:59As you make more and more progress,

24:02despite having this recursive self-improvement component,

24:05you are encountering exponential friction.

24:09Like the more researchers you have

24:11working on different ideas,

24:13the more overhead you have

24:15in terms of communication across researchers.

24:18If you look at,

24:19you were mentioning quantum mechanics, right?

24:23Well, if you want to start making significant discoveries

24:26today, significant progress in quantum mechanics,

24:29there is an amount of knowledge

24:31you have to ingest, which is huge.

24:34So there's a very large overhead

24:36to even start to contribute.

24:39There's a large amount of overhead

24:40to synchronize across researchers and so on.

24:44And of course, the significant practical experiments

24:47are going to require exponentially expensive equipment

24:52because the easier ones have already been run, right?

24:56- So in your senses,

24:59there's no way escaping,

25:01there's no way of escaping this kind of friction

25:05with artificial intelligence systems.

25:09- Yeah, no, I think science is a very good way

25:12to model what would happen

25:14with a superhuman recursively self-improving AI.

25:17- That's your sense, I mean, the--

25:19- That's my intuition.

25:20It's not like a mathematical proof of anything.

25:24That's not my point.

25:25Like, I'm not trying to prove anything.

25:27I'm just trying to make an argument,

25:28to question the narrative of intelligence explosion,

25:32which is quite a dominant narrative.

25:33And you do get a lot of pushback if you go against it.

25:36Because, so for many people, right,

25:40AI is not just a subfield of computer science.

25:43It's more like a belief system.

25:44Like this belief that the world is headed towards an event,

25:49the singularity, past which, you know,

25:52AI will become, will go exponential very much

25:58and the world will be transformed

25:59and humans will become obsolete.

26:01And if you go against this narrative,

26:04because it is not really a scientific argument,

26:07but more of a belief system,

26:09it is part of the identity of many people.

26:12If you go against this narrative,

26:13it's like you're attacking the identity

26:15of people who believe in it.

26:16It's almost like saying God doesn't exist or something.

26:19- Right.

26:20- So you do get a lot of pushback

26:22if you try to question these ideas.

26:25- First of all, I believe most people,

26:27they might not be as eloquent or explicit as you're being,

26:30but most people in computer science

26:32and most people who actually have built

26:34anything that you could call AI, quote unquote,

26:37would agree with you.

26:39They might not be describing in the same kind of way.

26:41It's more, so the pushback you're getting

26:45is from people who get attached to the narrative

26:48from not from a place of science,

26:51but from a place of imagination.

26:53- That's correct, that's correct.

26:54- So why do you think that's so appealing?

26:56Because the usual dreams that people have

27:01when you create a superintelligent system

27:04past the singularity, that what people imagine

27:06is somehow always destructive.

27:08Do you have, if you were put on your psychology hat,

27:12what's, why is it so appealing to imagine

27:17the ways that all of human civilization will be destroyed?

27:20- I think it's a good story.

27:22You know, it's a good story.

27:23And very interestingly, it mirrors

27:26religious stories, right?

27:28Religious mythology.

27:30If you look at the mythology of most civilizations,

27:34it's about the world being headed towards some final events

27:38in which the world will be destroyed

27:40and some new world order will arise

27:42that will be mostly spiritual,

§04Transcript · 27:44–36:59

27:44like the apocalypse followed by paradise probably, right?

27:49It's a very appealing story on a fundamental level.

27:52And we all need stories.

27:54We all need stories to structure the way we see the world,

27:58especially at timescales that are beyond

28:01our ability to make predictions, right?

28:04- So on a more serious, non-exponential explosion question,

28:09do you think there will be a time

28:14when we'll create something like human-level intelligence

28:19or intelligent systems that will make you sit back

28:23and be just surprised at damn how smart this thing is?

28:28That doesn't require exponential growth

28:30or exponential improvement,

28:32but what's your sense of the timeline and so on

28:35that you'll be really surprised at certain capabilities?

28:41And we'll talk about limitations in deep learning.

28:42So when do you, do you think in your lifetime

28:44you'll be really damn surprised?

28:46- Around 2013, 2014, I was many times surprised

28:51by the capabilities of deep learning, actually.

28:53- Yeah.

28:54- That was before we had assessed exactly

28:55what deep learning could do and could not do.

28:57And it felt like a time of immense potential.

29:00And then we started narrowing it down,

29:03but I was very surprised.

29:04So I would say it has already happened.

29:07- Was there a moment, there must've been a day in there

29:10where your surprise was almost bordering on the belief

29:15of the narrative that we just discussed.

29:19Was there a moment, 'cause you've written quite eloquently

29:22about the limits of deep learning.

29:23Was there a moment that you thought

29:25that maybe deep learning is limitless?

29:27- No, I don't think I've ever believed this.

29:32What was really shocking is that it's worked.

29:35- It worked at all, yeah.

29:36- Yeah.

29:37But there's a big jump between being able to do

29:41really good computer vision and human level intelligence.

29:44So I don't think at any point, I wasn't an impression

29:49that the results we got in computer vision

29:51meant that we were very close to human level intelligence.

29:54I don't think we were very close to human level intelligence.

29:56I do believe that there's no reason why we won't achieve it

30:00at some point.

30:01I also believe that, you know, it's the problem

30:06with talking about human level intelligence

30:08that implicitly you're considering like an axis

30:12of intelligence with different levels.

30:14But that's not really how intelligence works.

30:16Intelligence is very multidimensional.

30:19And so there's the question of capabilities,

30:22but there's also the question of being human-like.

30:25And it's two very different things.

30:27Like you can build potentially very advanced

30:29intelligent agents that are not human-like at all.

30:32And you can also build very human-like agents.

30:35And these are two very different things, right?

30:37- Right.

30:38Let's go from the philosophical to the practical.

30:42Can you give me a history of Keras

30:44and all the major deep learning frameworks

30:46that you kind of remember in relation to Keras

30:48and in general, TensorFlow, Theano, the old days.

30:52Can you give a brief overview, Wikipedia style history

30:55and your role in it before we return to AGI discussions?

30:59- Yeah, that's a broad topic.

31:00So I started working on Keras.

31:04It was a name Keras at the time.

31:06I actually picked the name like just the day

31:08I was going to release it.

31:10So I started working on it in February, 2015.

31:14And so at the time, there weren't too many people

31:17working on deep learning, maybe like fewer than 10,000.

31:20The software tooling was not really developed.

31:22So the main deep learning library was Caffe,

31:28which was mostly C++.

31:30- Why do you say Caffe was the main one?

31:32- Caffe was vastly more popular than Theano

31:36in late 2014, early 2015.

31:38Caffe was the one library that everyone was using

31:42for computer vision.

31:43- And computer vision was the most popular problem

31:46that you were working at the time.

31:47- Absolutely, like Covenants was like the subfield

31:49of deep learning that everyone was working on.

31:53So myself, so in late 2014, I was actually interested

31:58in RNNs, in Recurrent Neural Networks,

32:01which was a very niche topic at the time.

32:05It really took off around 2016.

32:08And so I was looking for good tools.

32:11I had used Torch 7, I had used Theano,

32:14used Theano a lot in Kaggle competitions.

32:17I had used Caffe, and there was no good solution

32:24for RNNs at the time.

32:26There was no reusable open source implementation

32:28of an LSTM, for instance.

32:30So I decided to build my own.

32:33And at first, the pitch for that was,

32:35it was gonna be mostly around LSTM,

32:39Recurrent Neural Networks.

32:40It was gonna be in Python.

32:41An important decision at the time

32:44that was kind of not obvious is that the models

32:47would be defined via Python code,

32:50which was kind of like going against the mainstream

32:54at the time because Caffe, PyLearn 2, and so on,

32:58like all the big libraries were actually going

33:00with the approach of having static configuration files

33:03in YAML to define models.

33:05So some libraries were using code to define models,

33:09like Torch 7, obviously, but that was not.

33:11Python.

33:12Lasagne was like a Theano-based, very early library

33:16that was, I think, developed, I'm not sure exactly,

33:18probably late 2014.

33:20- It's Python as well.

33:21- It's Python as well.

33:22It was like on top of Theano.

33:24And so I started working on something,

33:28and the value proposition at the time was that

33:32not only that what I think was the first reusable

33:36open source implementation of LSTM,

33:40you could combine RNNs and Covenants

33:44with the same library, which was not really possible before.

33:46Like Caffe was only doing Covenants.

33:49And it was kind of easy to use because,

33:53so before I was using Theano, I was actually using Scikit-Learn

33:55and I loved Scikit-Learn for its usability.

33:58So I drew a lot of inspiration from Scikit-Learn

34:01when I met Keras.

34:02It's almost like Scikit-Learn for neural networks.

34:04- Yeah, the fit function.

34:06- Exactly, the fit function.

34:07Like reducing a complex string loop

34:10to a single function call, right?

34:12And of course, some people will say,

34:14this is hiding a lot of details,

34:16but that's exactly the point, right?

34:18The magic is the point.

34:20So it's magical, but in a good way.

34:22It's magical in the sense that it's delightful, right?

34:25- Yeah, I'm actually quite surprised.

34:27I didn't know that it was born out of desire

34:29to implement RNNs and LSTMs.

34:32- It was.

34:33- That's fascinating.

34:34So you were actually one of the first people

34:36to really try to attempt

34:37to get the major architectures together.

34:40And it's also interesting,

34:42you made me realize that that was a design decision at all,

34:45is defining the model and code.

34:47Just, I'm putting myself in your shoes,

34:49whether the YAML, especially if CAFE was the most popular.

34:53- It was the most popular by far at the time.

34:56- If I were, yeah, I didn't like the YAML thing,

34:59but it makes more sense that you will put

35:02in a configuration file the definition of a model.

35:05That's an interesting gutsy move

35:07to stick with defining it in code.

35:10Just if you look back.

35:11- Other libraries were doing it as well,

35:13but it was definitely the more niche option.

35:16- Yeah, okay, Keras and then--

35:18- Keras, so I released Keras in March, 2015,

35:21and it got users pretty much from the start.

35:24So the deep learning community

35:25was very, very small at the time.

35:27Lots of people were starting to be interested in LSTM.

35:30So it was gonna release it at the right time

35:32because it was offering an easy to use LSTM implementation.

35:35Exactly at the time where lots of people started

35:37to be intrigued by the capabilities of RNN, RNN, so NLP.

35:42So it grew from there.

35:43Then I joined Google about six months later,

35:51and that was actually completely unrelated to Keras.

35:54I actually joined a research team

35:57working on image classification,

35:59mostly like computer vision.

36:00So I was doing computer vision research at Google initially.

36:03And immediately when I joined Google,

36:05I was exposed to the early internal version of TensorFlow.

36:10And the way it appeared to me at the time,

36:13and it was definitely the way it was at the time,

36:15is that this was an improved version of Theano.

36:20So I immediately knew I had to port Keras

36:24to this new TensorFlow thing.

36:26And I was actually very busy as a new Googler.

36:31So I had not time to work on that.

36:34But then in November, I think it was November 2015,

36:38TensorFlow got released.

36:41And it was kind of like my wake up call that,

36:44hey, I had to actually go and make it happen.

36:47So in December, I ported Keras to run on top of TensorFlow.

36:52But it was not exactly a port,

36:53it was more like a refactoring

36:55where I was abstracting away all the backend functionality

36:59into one module so that the same code base

§05Transcript · 37:02–46:37

37:02could run on top of multiple backends.

37:04So on top of TensorFlow or Theano.

37:07And for the next year, Theano stayed as the default option.

37:12It was easier to use, somewhat less buggy.

37:20It was much faster, especially when it came to Ornans.

37:23But eventually, TensorFlow overtook it.

37:27- And TensorFlow, the early TensorFlow,

37:30has similar architectural decisions as Theano.

37:33So it was a natural transition.

37:37- Yeah, absolutely.

37:38- So what, I mean, that's still Keras

37:41as a side, almost fun project, right?

37:45- Yeah, so it was not my job assignment.

37:48I was doing it on the side.

37:52And even though it grew to have a lot of users

37:55for a deep learning library at the time, like Stroud 2016,

37:59but I wasn't doing it as my main job.

38:02So things started changing in,

38:04I think it must have been maybe October 2016.

38:09So one year later.

38:11So Rajat, who was the lead on TensorFlow,

38:15basically showed up one day in our building

38:19where I was doing research and things like,

38:21so I did a lot of computer vision research,

38:24also collaborations with Christian Zugedi

38:27and deep learning for theorem proving.

38:29It was a really interesting research topic.

38:32And so Rajat was saying, "Hey, we saw Keras, we like it.

38:39We saw that you're at Google.

38:42Why don't you come over for like a quarter

38:45and work with us?"

38:47And I was like, "Yeah, that sounds like a great opportunity.

38:49Let's do it."

38:50And so I started working on integrating the Keras API

38:55into TensorFlow more tightly.

38:57So what followed up is a sort of like temporary

39:02TensorFlow only version of Keras

39:05that was in TensorFlow.com Trib for a while.

39:09And finally moved to TensorFlow Core.

39:12And I've never actually gotten back

39:15to my old team doing research.

39:17- Well, it's kind of funny that somebody like you

39:22who dreams of, or at least sees the power of AI systems

39:27that reason and theorem proving we'll talk about

39:31has also created a system that makes

39:34the most basic kind of Lego building

39:39that is deep learning, super accessible, super easy.

39:42So beautifully so.

39:43It's a funny irony that you're both,

39:47you're responsible for both things.

39:49But so TensorFlow 2.0 is kind of, there's a sprint.

39:53I don't know how long it'll take,

39:55but there's a sprint towards the finish.

39:56What do you look, what are you working on these days?

40:01What are you excited about?

40:02What are you excited about in 2.0?

40:04I mean, eager execution.

40:05There's so many things that just make it a lot easier

40:08to work.

40:09What are you excited about?

40:11And what's also really hard?

40:13What are the problems you have to kind of solve?

40:15- So I've spent the past year and a half

40:17working on TensorFlow 2.0.

40:20It's been a long journey.

40:22I'm actually extremely excited about it.

40:25I think it's a great product.

40:26It's a delightful product compared to TensorFlow 1.0.

40:29We've made huge progress.

40:31So on the Keras side, what I'm really excited about is that,

40:37so, you know, previously Keras has been this very easy

40:42to use high-level interface to do deep learning.

40:46But if you wanted to, you know,

40:50if you wanted a lot of flexibility,

40:53the Keras framework, you know,

40:55was probably not the optimal way to do things

40:58compared to just writing everything from scratch.

41:01So in some way, the framework was getting in the way.

41:04And in TensorFlow 2.0, you don't have this at all,

41:07actually, you have the usability of the high-level interface,

41:11but you have the flexibility of this lower-level interface.

41:14And you have this spectrum of workflows

41:17where you can get more or less usability

41:21and flexibility trade-offs depending on your needs, right?

41:26You can write everything from scratch

41:29and you get a lot of help doing so by, you know,

41:33subclassing models and writing some train loops

41:36using ego execution.

41:38It's very flexible.

41:39It's very easy to debug.

41:40It's very powerful.

41:41But all of this integrates seamlessly

41:44with higher-level features up to, you know,

41:47the classic Keras workflows,

41:49which are very scikit-learn-like

41:51and, you know, are ideal for a data scientist,

41:56machine learning engineer type of profile.

41:58So now you can have the same framework

42:00offering the same set of APIs

42:02that enable a spectrum of workflows

42:05that are more or less low-level, more or less high-level

42:08that are suitable for, you know,

42:10profiles ranging from researchers to data scientists

42:14and everything in between.

42:15- Yeah, so that's super exciting.

42:16I mean, it's not just that,

42:18it's connected to all kinds of tooling.

42:21You can go on mobile, you can go with TensorFlow Lite,

42:24you can go in the cloud with serving and so on,

42:27and all is connected together.

42:28And some of the best software written ever

42:31is often done by one person, sometimes two.

42:37So with Google, you're now seeing sort of Keras

42:40having to be integrated in TensorFlow,

42:42I'm sure has a ton of engineers working on.

42:46So, and there's, I'm sure,

42:48a lot of tricky design decisions to be made.

42:52How does that process usually happen

42:54from at least your perspective?

42:56What are the debates like?

42:59Is there a lot of thinking,

43:04considering different options and so on?

43:06- Yes.

43:08So a lot of the time I spend at Google

43:12is actually discussing design discussions, right?

43:17Writing design docs,

43:18participating in design review meetings and so on.

43:22This is, you know, as important

43:23as actually writing the code.

43:25- Right.

43:26- So there's a lot of thoughts,

43:27there's a lot of thoughts and a lot of care

43:29that is taken in coming up with these decisions

43:34and taking into account all of our users

43:37because TensorFlow has this extremely diverse user base,

43:40right?

43:41It's not like just one user segment

43:43where everyone has the same needs.

43:45We have small scale production users,

43:47large scale production users.

43:49We have startups, we have researchers,

43:52you know, it's all over the place.

43:55And we have to cater to all of their needs.

43:57- If I just look at the standard debates of C++ or Python,

44:02there's some heated debates.

44:03Do you have those at Google?

44:05I mean, they're not heated in terms of emotionally,

44:08but there's probably multiple ways to do it right.

44:10So how do you arrive through those design meetings

44:13at the best way to do it?

44:15Especially in deep learning where the field is evolving

44:19as you're doing it.

44:20Is there some magic to it?

44:23There's some magic to the process?

44:25- I don't know if there's magic to the process,

44:28but there definitely is a process.

44:30So making design decisions

44:33about satisfying a set of constraints,

44:36but also trying to do so in the simplest way possible,

44:39because this is what can be maintained,

44:42this is what can be expanded in the future.

44:45So you don't want to naively satisfy the constraints

44:49by just, you know, for each capability you need available,

44:51you're gonna come up with one argument,

44:53a new API and so on.

44:54You want to design APIs that are modular

44:59and hierarchical so that they have an API surface

45:04that is as small as possible.

45:06And you want this modular hierarchical architecture

45:11to reflect the way that domain experts

45:14think about the problem.

45:16Because as a domain expert,

45:17when you are reading about a new API,

45:19you're reading a tutorial or some docs pages,

45:23you already have a way

45:26that you're thinking about the problem.

45:28You already have like certain concepts in mind

45:32and you're thinking about how they relate together.

45:35And when you're reading docs,

45:37you're trying to build as quickly as possible

45:40a mapping between the concepts featured in your API

45:45and the concepts in your mind.

45:46So you're trying to map your mental model

45:48as a domain expert to the way things work in the API.

45:53So you need an API and an underlying implementation

45:57that are reflecting the way people think about these things.

46:00- So you're minimizing the time it takes to do the mapping.

46:02- Yes, minimizing the time,

46:04the cognitive load there is

46:06in ingesting this new knowledge about your API.

46:10An API should not be self-referential

46:13or referring to implementation details.

46:15It should only be referring to domain specific concepts

46:19that people already understand.

46:21- Brilliant.

46:24So what's the future of Keras and TensorFlow look like?

46:27What does TensorFlow 3.0 look like?

46:29- So that's kind of too far in the future for me to answer,

46:33especially since I'm not even the one making these decisions.

46:37- Okay.

§06Transcript · 46:39–56:10

46:39- But so from my perspective,

46:41which is just one perspective

46:43among many different perspectives on the TensorFlow team,

46:46I'm really excited by developing even higher level APIs,

46:52higher level than Keras.

46:53I'm really excited by hyper parameter tuning,

46:56by automated machine learning, AutoML.

46:59I think the future is not just, you know,

47:03defining a model like you were assembling Lego blocks

47:07and then collect fit on it.

47:09It's more like an automagical model

47:13that would just look at your data

47:16and optimize the objective you're after, right?

47:19So that's what I'm looking into.

47:23- Yeah, so you put the baby into a room with the problem

47:26and come back a few hours later

47:28with a fully solved problem.

47:30- Exactly, it's not like a box of Legos.

47:33It's more like the combination of a kid

47:35that's really good at Legos and a box of Legos

47:38and just building the thing on its own.

47:41- Very nice.

47:42So that's an exciting future.

47:44And I think there's a huge amount of applications

47:46and revolutions to be had under the constraints

47:50of the discussion we previously had.

47:52But what do you think are the current limits

47:56of deep learning?

47:57If we look specifically at these function approximators

48:02that tries to generalize from data.

48:06So you've talked about local versus extreme generalization.

48:10You mentioned that neural networks don't generalize well,

48:13humans do.

48:14So there's this gap.

48:16So, and you've also mentioned that generalization,

48:19extreme generalization requires something like reasoning

48:22to fill those gaps.

48:23So how can we start trying to build systems like that?

48:27- Right, yeah, so this is by design, right?

48:30Deep learning models are like huge parametric models

48:35differentiable, so continuous,

48:39that go from an input space to an output space.

48:42And they're trained with gradient descent.

48:44So they're trained pretty much point by point.

48:47They're learning a continuous geometric morphing

48:50from an input vector space to an output vector space.

48:54And because this is done point by point,

48:59a deep neural network can only make sense

49:02of points in experience space that are very close

49:05to things that it has already seen in the stream data.

49:08At best, it can do interpolation across points.

49:12But that means, you know,

49:15it means in order to train your network,

49:17you need a dense sampling of the input cross output space,

49:21almost a point by point sampling,

49:25which can be very expensive

49:26if you're dealing with complex real world problems

49:29like autonomous driving, for instance, or robotics.

49:33It's doable if you're looking at the subset

49:36of the visual space, but even then,

49:37it's still fairly expensive.

49:38You still need millions of examples.

49:40And it's only gonna be able to make sense of things

49:44that are very close to what it has seen before.

49:46And in contrast to that,

49:48well, of course you have human intelligence,

49:50but even if you're not looking at human intelligence,

49:53you can look at very simple rules, algorithms.

49:56If you have a symbolic rule,

49:58it can actually apply to a very, very large set of inputs

50:03because it is abstract.

50:04It is not obtained by doing a point by point mapping, right?

50:09For instance, if you try to learn a sorting algorithm

50:14using a deep neural network,

50:15well, you're very much limited to learning point by point

50:18what the sorted representation of this specific list

50:23is like, but instead you could have a very, very simple

50:28sorting algorithm written in a few lines.

50:31Maybe it's just two nested loops

50:34and it can process any list at all because it is abstract,

50:40because it is a set of rules.

50:42So deep learning is really like point by point

50:45geometric morphings, morphings, train, risk, and descent.

50:48And meanwhile, abstract rules can generalize much better.

50:53And I think the future is really to combine the two.

50:56- So how do we, do you think, combine the two?

50:59How do we combine good point by point functions

51:03with programs, which is what the symbolic AI type systems?

51:08- Yeah.

51:09- At which levels the combination happen?

51:12I mean, obviously we're jumping into the realm

51:15of where there's no good answers.

51:17You just kind of ideas and intuitions and so on.

51:20- Well, if you look at the really successful AI systems

51:23today, I think they are already hybrid systems

51:26that are combining symbolic AI with deep learning.

51:29For instance, successful robotics systems

51:32are already mostly model-based, rule-based,

51:36things like planning algorithms and so on.

51:39At the same time, they're using deep learning

51:42as perception modules.

51:43Sometimes they're using deep learning as a way to inject

51:47fuzzy intuition into a rule-based process.

51:50If you look at the system like in a self-driving car,

51:54it's not just one big end-to-end neural network,

51:57you know, that wouldn't work at all.

51:59Precisely because in order to train that,

52:00you would need a dense sampling of experience space

52:05when it comes to driving,

52:06which is completely unrealistic, obviously.

52:08Instead, the self-driving car is mostly symbolic,

52:13you know, it's software, it's programmed by hand.

52:18So it's mostly based on explicit models,

52:21in this case, mostly 3D models of the environment

52:25around the car, but it's interfacing with the real world

52:29using deep learning modules, right?

52:31- Right, so the deep learning there serves as a way

52:33to convert the raw sensory information

52:36to something usable by symbolic systems.

52:38Okay, well, let's linger on that a little more.

52:42So dense sampling from input to output.

52:45You said it's obviously very difficult.

52:48Is it possible?

52:50- In the case of self-driving, you mean?

52:51- Let's say self-driving, right?

52:53Self-driving, for many people,

52:55let's not even talk about self-driving,

52:59let's talk about steering, so staying inside the lane.

53:05Lane following, yeah, it's definitely a problem

53:07you can solve with an end-to-end deep learning model,

53:08but that's like one small subset.

53:10- Hold on a second.

53:11I don't know why you're jumping from the extreme so easily,

53:14'cause I disagree with you on that.

53:16I think, well, it's not obvious to me

53:21that you can solve lane following.

53:23- No, it's not obvious.

53:24I think it's doable.

53:25I think in general, you know, there is no hard limitations

53:30to what you can learn with a deep neural network,

53:33as long as the search space is rich enough,

53:38is flexible enough, and as long as you have

53:42this dense sampling of the input cross output space.

53:45The problem is that this dense sampling

53:47could mean anything from 10,000 examples

53:51to like trillions and trillions.

53:52- So that's my question.

53:54So what's your intuition?

53:56And if you could just give it a chance

53:58and think what kind of problems can be solved

54:01by getting a huge amounts of data

54:04and thereby creating a dense mapping.

54:08So let's think about natural language dialogue,

54:12the Turing test.

54:14Do you think the Turing test can be solved

54:17with a neural network alone?

54:21- Well, the Turing test is all about tricking people

54:24into believing they're talking to a human.

54:26And I don't think that's actually very difficult

54:29because it's more about exploiting human perception

54:34and not so much about intelligence.

54:37There's a big difference between mimicking

54:39intelligent behavior and actual intelligent behavior.

54:42- So, okay, let's look at maybe the Alexa Prize and so on,

54:45the different formulations of the natural language

54:47conversation that are less about mimicking

54:50and more about maintaining a fun conversation

54:52that lasts for 20 minutes.

54:54That's a little less about mimicking

54:56and that's more about, I mean,

54:58it's still mimicking,

54:59but it's more about being able to carry forward

55:01a conversation with all the tangents that happen

55:03in dialogue and so on.

55:05Do you think that problem is learnable

55:08with this kind of, with a neural network

55:11that does the point-to-point mapping?

55:14- So I think it would be very, very challenging

55:16to do this with deep learning.

55:17I don't think it's out of the question either.

55:21I wouldn't rule it out.

55:23- The space of problems that can be solved

55:25with a large neural network.

55:26What's your sense about the space of those problems?

55:30So useful problems for us.

55:32- In theory, it's infinite, right?

55:34You can solve any problem.

55:36In practice, while deep learning is a great fit

55:39for perception problems, in general,

55:42any problem which is naturally amenable

55:47to explicit handcrafted rules

55:50or rules that you can generate by exhaustive search

55:53over some program space.

55:56So perception, artificial intuition,

55:59as long as you have a sufficient trained data set.

56:03- And that's the question.

56:04I mean, perception, there's interpretation

56:06and understanding of the scene,

56:08which seems to be outside the reach

56:10of current perception systems.

§07Transcript · 56:13–1:04:54

56:13So do you think larger networks will be able

56:15to start to understand the physics

56:18and the physics of the scene,

56:21the three-dimensional structure and relationships

56:23of objects in the scene and so on,

56:25or really that's where Symbolica has to step in?

56:28- Well, it's always possible to solve these problems

56:34with deep learning.

56:36It's just extremely inefficient.

56:38A model would be, an explicit rule-based abstract model

56:42would be a far better, more compressed representation

56:45of physics than learning just this mapping

56:48between in this situation, this thing happens.

56:51If you change the situation slightly,

56:52then this other thing happens and so on.

56:54- Do you think it's possible to automatically generate

56:57the programs that would require that kind of reasoning?

57:02Or does it have to, so the way the expert systems fail,

57:05there's so many facts about the world

57:07had to be hand-coded in.

57:08Do you think it's possible to learn those logical statements

57:13that are true about the world and their relationships?

57:17Do you think, I mean, that's kind of what theorem proving

57:20at a basic level is trying to do, right?

57:22- Yeah, except it's much harder to formulate statements

57:26about the world compared to formulating

57:28mathematical statements.

57:30Statements about the world tend to be subjective.

57:32So can you learn rule-based models?

57:39- Yes.

57:40- Yes, definitely.

57:41That's the field of program synthesis.

57:43However, today we just don't really know how to do it.

57:48So it's very much a graph search or tree search problem.

57:52And so we are limited to the sort of tree search

57:56and graph search algorithms that we have today.

57:58Personally, I think genetic algorithms are very promising.

58:02- So it's almost like genetic programming.

58:04- Genetic programming, exactly.

58:05- Can you discuss the field of program synthesis?

58:08Like how many people are working and thinking about it?

58:13What, where we are in the history of program synthesis

58:17and what are your hopes for it?

58:20- Well, if it were deep learning, this is like the '90s.

58:23(laughing)

58:24So meaning that we already have existing solutions.

58:29We are starting to have some basic understanding

58:34of what this is about,

58:35but it's still a field that is in its infancy.

58:37There are very few people working on it.

58:40There are very few real-world applications.

58:42So the one real-world application I'm aware of

58:47is Flash Fill in Excel.

58:50It's a way to automatically learn very simple programs

58:55to format cells in an Excel spreadsheet

58:58from a few examples.

59:00For instance, learning a way to format a date,

59:02things like that.

59:02- Oh, that's fascinating.

59:03- Yeah.

59:04- You know, okay, that's a fascinating topic.

59:06I always wonder when I provide a few samples to Excel,

59:10what it's able to figure out.

59:12Like just giving it a few dates.

59:15What are you able to figure out

59:16from the pattern I just gave you?

59:18That's a fascinating question.

59:19And it's fascinating whether that's learnable patterns.

59:23And you're saying they're working on that.

59:24- Yeah.

59:25- How big is the toolbox currently?

59:28Are we completely in the dark?

59:29So if you said the '90s.

59:30- In terms of processes?

59:31No, so I would say,

59:35so maybe '90s is even too optimistic

59:37because by the '90s, you know,

59:38we already understood backprop.

59:41We already understood, you know,

59:42the engine of deep learning,

59:43even though we couldn't really see its potential quite.

59:47Today, I don't think we've found

59:48the engine of program synthesis.

59:50- So we're in the winter before backprop.

59:52- Yeah.

59:54In a way, yes.

59:55So I do believe program synthesis,

59:58in general, discrete search over rule-based models

60:02is gonna be a cornerstone of AI research

60:04in the next century, right?

60:06And that doesn't mean we're gonna drop deep learning.

60:10Deep learning is immensely useful.

60:11Like being able to learn is a very flexible,

60:16adaptable parametric model.

60:18So it's got in this sense,

60:19that's actually immensely useful.

60:20Like all it's doing is pattern cognition,

60:23but being good at pattern cognition,

60:24given lots of delays is just extremely powerful.

60:27So we are still gonna be working on deep learning

60:30and we're gonna be working on program synthesis.

60:31We're gonna be combining the two

60:33in increasingly automated ways.

60:35- So let's talk a little bit about data.

60:38You've tweeted.

60:40(laughs)

60:42About 10,000 deep learning papers have been written

60:45about hard coding priors about a specific task

60:48in a neural network architecture

60:49works better than a lack of a prior.

60:52Basically summarizing all these efforts,

60:55they put a name to an architecture,

60:56but really what they're doing is hard coding some priors

60:59that improve the performance of the system.

61:01But which gets straight to the point is probably true.

61:05So you say that you can always buy performance,

61:09buy in quotes performance by either training on more data,

61:12better data, or by injecting task information

61:15to the architecture of the pre-processing.

61:18However, this isn't informative

61:19about the generalization power of the techniques used,

61:22the fundamental ability to generalize.

61:24Do you think we can go far by coming up with better methods

61:28for this kind of cheating,

61:29for better methods of large-scale annotation of data?

61:33So building better priors.

61:35- If you had made it, it's not cheating anymore.

61:37- Right, I'm joking about the cheating,

61:39but large-scale, so basically I'm asking

61:43about something that hasn't, from my perspective,

61:48been researched too much is exponential improvement

61:53in annotation of data.

61:55Do you often think about-

61:58- I think it's actually been researched quite a bit.

62:00You just don't see publications about it

62:02because people who publish papers

62:05are gonna publish about known benchmarks.

62:07Sometimes they're gonna release a new benchmark.

62:09People who actually have real-world,

62:11large-scale deep learning problems,

62:13they're gonna spend a lot of resources

62:15into data annotation and good data annotation pipelines,

62:18but you don't see any papers about it.

62:19- That's interesting.

62:20So do you think, certainly resources,

62:22but do you think there's innovation happening?

62:24- Oh yeah, definitely.

62:25To clarify the point in the twist,

62:28so machine learning in general

62:30is the science of generalization.

62:33You want to generate knowledge that can be reused

62:38across different datasets, across different tasks.

62:42And if instead you're looking at one dataset

62:45and then you are hard-coding knowledge

62:49about this task into your architecture,

62:51this is no more useful than training a network

62:55and then saying, "Oh, I found these weight values

62:58"perform well," right?

63:01So David Ha, I don't know if you know David,

63:05he had a paper the other day

63:07about weight-agnostic neural networks.

63:10And this was a very interesting paper

63:12because it really illustrates the fact that an architecture,

63:16even without weights, an architecture is knowledge

63:20about a task, it encodes knowledge.

63:23And when it comes to architectures

63:25that are handcrafted by researchers,

63:29in some cases it is very, very clear

63:32that all they are doing is artificially

63:35re-encoding the template that corresponds

63:39to the proper way to solve a task

63:44encoding a given dataset.

63:45For instance, I know if you've looked at the Baby dataset,

63:50which is about natural language question answering,

63:53it is generated by an algorithm.

63:55So this is a question-answer pairs

63:57that are generated by an algorithm.

63:59The algorithm is solving a certain template.

64:01Turns out if you craft a network

64:04that literally encodes this template,

64:06you can solve this dataset with nearly 100% accuracy.

64:09But that doesn't actually tell you anything

64:12about how to solve question answering in general,

64:15which is the point.

64:17- The question is just to linger on it,

64:19whether it's from the data side

64:20or from the size of the network.

64:22I don't know if you've read the blog post

64:25by Rich Sutton, "The Bitter Lesson,"

64:27where he says, "The biggest lesson that we can read

64:30"from 70 years of AI research is that general methods

64:33"that leverage computation are ultimately

64:35"the most effective."

64:37So as opposed to figuring out methods

64:39that can generalize effectively,

64:41do you think we can get pretty far

64:46by just having something that leverages computation

64:50and the improvement of computation?

64:51- Yeah, so I think Rich is making a very good point,

64:54which is that a lot of these papers,

§08Transcript · 1:04:56–1:15:01

64:56which are actually all about manually hard-coding

65:00prior knowledge about a task into some system,

65:04doesn't have to be deep learning architecture,

65:05but into some system, right?

65:07You know, these papers are not actually making any impact.

65:11Instead, what's making really long-term impact

65:14is very simple, very general systems

65:18that are really agnostic to all these tricks,

65:21because these tricks do not generalize.

65:23And of course, the one general and simple thing

65:27that you should focus on is that which leverages computation,

65:32because computation, the availability

65:36of large-scale computation has been increasing exponentially

65:39following Moore's law.

65:40So if your algorithm is all about exploiting this,

65:44then your algorithm is suddenly exponentially improving.

65:47So I think Rich is definitely right.

65:52However, you know, he's right about the past 70 years.

65:57He's like assessing the past 70 years.

65:59I am not sure that this assessment will still hold true

66:02for the next 70 years.

66:04It might to some extent, I suspect it will not,

66:08because the truth of his assessment

66:11is a function of the context, right?

66:14In which this research took place.

66:16And the context is changing.

66:18Like Moore's law might not be applicable anymore,

66:21for instance, in the future.

66:23And I do believe that, you know,

66:26when you tweak one aspect of a system,

66:31when you exploit one aspect of a system,

66:32some other aspects starts becoming the bottleneck.

66:36Let's say you have unlimited computation.

66:38Well, then data is the bottleneck.

66:41And I think we're already starting to be in a regime

66:44where our systems are so large in scale

66:47and so data-hungry, the data today

66:49and the quality of data and the scale of data

66:51is the bottleneck.

66:53And in this environment,

66:54the bitter lesson from Rich

66:58is it's not gonna be true anymore, right?

67:00So I think we are gonna move from a focus on a scale

67:05of a competition scale to focus on data efficiency.

67:09- Data efficiency.

67:10So that's getting to the question of symbolic AI,

67:13but to linger on the deep learning approaches,

67:16do you have hope for either unsupervised learning

67:19or reinforcement learning,

67:20which are ways of being more data efficient

67:25in terms of the amount of data they need

67:29that required human annotation?

67:31- So unsupervised learning and reinforcement learning

67:34are frameworks for learning,

67:36but they're not like any specific technique.

67:39So usually when people say reinforcement learning,

67:41what they really mean is deep reinforcement learning,

67:43which is like one approach,

67:45which is actually very questionable.

67:47The question I was asking was unsupervised learning

67:50with deep neural networks and deep reinforcement learning.

67:54- Well, these are not really data efficient

67:56because you're still leveraging, you know,

67:58this huge parametric models,

68:00trying point by point with gradient descent.

68:02It is more efficient in terms of the number of annotations,

68:08the density of annotations you need.

68:09So the idea being to learn the latent space

68:13around which the data is organized

68:15and then map the sparse annotations into it.

68:18And sure, I mean, that's clearly a very good idea.

68:21It's not really a topic I would be working on,

68:26but it's clearly a good idea.

68:27- So it would get us to solve some problems that-

68:31- It will get us to incremental improvements

68:34in label data efficiency.

68:38- Do you have concerns about short-term

68:42or long-term threats from AI,

68:44from artificial intelligence?

68:46- Yes, definitely to some extent.

68:50- And what's the shape of those concerns?

68:52- This is actually something I've briefly written about,

68:56but the capabilities of deep learning technology

69:01can be used in many ways that are concerning

69:06from mass surveillance with things like facial recognition,

69:11in general, tracking lots of data about everyone

69:15and then being able to making sense of this data

69:18to do identification, to do prediction.

69:21That's concerning.

69:23That's something that's being very aggressively pursued

69:26by totalitarian states like China.

69:29One thing I am very much concerned about is that

69:34our lives are increasingly online,

69:40are increasingly digital, made of information,

69:43made of information consumption and information production

69:46or digital footprints, I would say.

69:51And if you absorb all of this data

69:56and you are in control of where you consume information,

70:01social networks and so on,

70:03recommendation engines,

70:07then you can build a sort of reinforcement loop

70:11for human behavior.

70:13You can observe the state of your mind at time T.

70:18You can predict how you would react

70:21to different pieces of content,

70:22how to get you to move your mind in a certain direction.

70:27And then you can feed you the specific piece of content

70:32that would move you in a specific direction.

70:35And you can do this at scale,

70:37at scale in terms of doing it continuously in real time.

70:44You can also do it at scale in terms of scaling this

70:47to many, many people, to entire populations.

70:50So potentially artificial intelligence,

70:53even in its current state,

70:55if you combine it with the internet,

70:58with the fact that we have,

71:00all of our lives are moving to digital devices

71:04and digital information consumption and creation,

71:06what you get is the possibility

71:10to achieve mass manipulation of behavior

71:14and mass psychological control.

71:16And this is a very real possibility.

71:18- Yeah, so you're talking about

71:20any kind of recommender system?

71:21- Yeah.

71:22- Let's look at the YouTube algorithm, Facebook,

71:26anything that recommends content you should watch next.

71:29And it's fascinating to think that there's some aspects

71:33of human behavior that you can,

71:36say a problem of,

71:41is this person hold Republican beliefs or Democratic beliefs

71:45and it's a trivial, that's an objective function

71:50and you can optimize and you can measure

71:52and you can turn everybody into a Republican

71:54or everybody into a Democrat.

71:55- Absolutely, yeah.

71:56I do believe it's true.

71:57So the human mind is very,

72:02if you look at the human mind as a kind of computer program,

72:05it is a very large exploit surface, right?

72:07It has many, many vulnerabilities.

72:09- Exploit surfaces, yeah.

72:10- Ways you can control it.

72:13For instance, when it comes to your political beliefs,

72:16this is very much tied to your identity.

72:19So for instance, if I'm in control of your newsfeed

72:23on your favorite social media platforms,

72:26this is actually where you're getting your news from.

72:29And I can, of course I can choose to only show you news

72:33that will make you see the world in a specific way, right?

72:37But I can also,

72:38create incentives for you to post

72:43about some political beliefs.

72:44And then when I get you to express a statement,

72:47if it's a statement that me as the controller,

72:51I want to reinforce,

72:53I can just show it to people who will agree

72:55and they will like it.

72:56And that will reinforce the statement in your mind.

72:59If this is a statement I want you to,

73:01this is a belief I want you to abandon,

73:05I can, on the other hand, show it to opponents, right?

73:09Will attack you.

73:10And then because they attack you at the very least,

73:12next time you will think twice about posting it.

73:16But maybe you will even, you know,

73:18stop believing this because you got pushback, right?

73:22So there are many ways in which

73:27social media platforms can potentially control your opinions.

73:30And today,

73:31so all of these things are already being controlled

73:36by AI algorithms.

73:38These algorithms do not have

73:39any explicit political goal today.

73:42While potentially they could,

73:44like if some totalitarian government

73:49takes over social media platforms

73:52and decides that now we are gonna use this

73:54not just for mass surveillance,

73:56but also for mass opinion control and behavior control,

73:59you know, very bad things could happen.

74:01But what's really fascinating

74:04and actually quite concerning is that

74:07even without an explicit intent to manipulate,

74:11you're already seeing very dangerous dynamics

74:14in terms of how these content recommendation

74:17algorithms behave.

74:19Because right now, the goal,

74:23the objective function of these algorithms

74:26is to maximize engagement, right?

74:28Which seems fairly innocuous at first, right?

74:32However, it is not because content

74:36that will maximally engage people, you know,

74:39get people to react in an emotional way,

74:43get people to click on something,

74:44it is very often content that, you know,

74:49is not healthy to the public discourse.

74:54For instance, fake news are far more likely

74:59to get you to click on them than real news,

75:01simply because they are not constrained to reality.

§09Transcript · 1:15:06–1:25:07

75:06So they can be as atrocious, as surprising,

75:11as good stories as you want,

75:13because they're artificial, right?

75:15- Yeah, to me, that's an exciting world

75:17because so much good can come.

75:19So there's an opportunity to educate people.

75:24You can balance people's worldview with other ideas.

75:29So there's so many objective functions,

75:33the space of objective functions

75:35that create better civilizations

75:37is large, arguably infinite.

75:40But there's also a large space that creates division

75:45and destruction, civil war, a lot of bad stuff.

75:50And the worry is, naturally,

75:56probably that space is bigger, first of all.

75:59And if we don't explicitly think about

76:01what kind of effects are going to be observed

76:06from different objective functions,

76:08then we're going to get into trouble.

76:10But the question is, how do we get into rooms

76:14and have discussions?

76:16So inside Google, inside Facebook, inside Twitter,

76:20and think about, okay, how can we drive up engagement

76:23and at the same time create a good society?

76:27Is it even possible to have

76:29that kind of philosophical discussion?

76:31- I think you can definitely try.

76:33So from my perspective,

76:34I would feel rather uncomfortable with companies

76:39that are in control of these news algorithms,

76:43with them making explicit decisions

76:45to manipulate people's opinions or behaviors,

76:50even if the intent is good,

76:52because that's a very totalitarian mindset.

76:55So instead, what I would like to see,

76:57it's probably never going to happen

76:58because it's not super realistic,

77:00but that's actually something I really care about.

77:02I would like all these algorithms

77:06to present configuration settings to their users

77:10so that the users can actually make the decision

77:13about how they want to be impacted

77:16by these information recommendation,

77:19content recommendation algorithms.

77:21For instance, as a user of something like YouTube

77:24or Twitter, maybe I want to maximize learning

77:28about a specific topic, right?

77:30So I want the algorithm to feed my curiosity, right?

77:35Which is in itself a very interesting problem.

77:38So instead of maximizing my engagement,

77:41it will maximize how fast and how much I'm learning.

77:44And it will also take into account the accuracy,

77:47hopefully, of the information I'm learning.

77:49So yeah, the user should be able to determine exactly

77:55how these algorithms are affecting their lives.

77:58I don't want actually any entity making decisions

78:03about in which direction

78:06they're going to try to manipulate me, right?

78:09I want technology.

78:11So AI, these algorithms are increasingly going to be

78:15our interface to a world

78:17that is increasingly made of information.

78:20And I want everyone to be in control of this interface,

78:25to interface with the world on their own terms.

78:29So if someone wants these algorithms

78:32to serve their own personal growth goals,

78:37they should be able to configure these algorithms

78:40in such a way.

78:41- Yeah, but so I know it's painful

78:44to have explicit decisions,

78:46but there is underlying explicit decisions,

78:51which is some of the most beautiful fundamental philosophy

78:54that we have before us, which is personal growth.

79:01If I want to watch videos from which I can learn,

79:04what does that mean?

79:08So if I have a checkbox that wants to emphasize learning,

79:11there's still an algorithm with explicit decisions in it

79:15that would promote learning.

79:17What does that mean for me?

79:19Like, for example, I've watched a documentary

79:20on flat earth theory, I guess.

79:23It was very, like, I learned a lot.

79:28I'm really glad I watched it.

79:29It was a friend recommended it to me.

79:31Not, 'cause I don't have such an allergic reaction

79:35to crazy people as my fellow colleagues do,

79:37but it was very eye-opening.

79:40And for others, it might not be.

79:42For others, they might just get turned off for that.

79:45Same with Republican and Democrat.

79:47And what, it's a non-trivial problem.

79:50And first of all, if it's done well,

79:53I don't think it's something that wouldn't happen,

79:56that YouTube wouldn't be promoting,

79:59or Twitter wouldn't be.

80:00It's just a really difficult problem.

80:02How do we do, how to give people control?

80:05- Well, it's mostly an interface design problem.

80:08- Right.

80:09- The way I see it, you want to create technology

80:11that's like a mentor or a coach or an assistant

80:16so that it's not your boss, right?

80:19You are in control of it.

80:22You are telling it what to do for you.

80:25And if you feel like it's manipulating you,

80:27it's not actually doing what you want.

80:31You should be able to switch to a different algorithm.

80:33- Right.

80:35So that's fine-tune control.

80:36And you kind of learn,

80:38you're trusting the human collaboration.

80:40I mean, that's how I see autonomous vehicles too,

80:41is giving as much information as possible,

80:44and you learn that dance yourself.

80:46Yeah, Adobe, I don't know if you use Adobe products

80:50for like Photoshop. - Yeah, I use Photoshop.

80:51- Yeah.

80:52They're trying to see if they can inject YouTube

80:55into their interface.

80:56Basically allow you to show you all these videos

80:59that, 'cause everybody's confused about what to do

81:02with features, so basically teach people by linking to,

81:07and that way it's an assistant that shows,

81:09uses videos as a basic element of information.

81:12Okay, so what practically should people do

81:18to try to fight against abuses of these algorithms

81:24or algorithms that manipulate us?

81:27- Honestly, it's a very, very difficult problem

81:29because to start with,

81:30there is very little public awareness of these issues.

81:33Very few people would think there's anything wrong

81:38with their newsfeed algorithm,

81:39even though there is actually something wrong already,

81:42which is that it's trying to maximize engagement

81:44most of the time, which has very negative side effects.

81:49So ideally, so the very first thing is to stop

81:54trying to purely maximize engagement,

81:59try to propagate content based on popularity, right?

82:04Instead, take into account the goals

82:11and the profiles of each user.

82:13So you will be, one example is for instance,

82:16when they look at topic recommendations on Twitter,

82:20it's like, you know, they have this news tab

82:24with switch recommendations, it's always the worst garbage

82:28because it's content that appeals to the smallest

82:33common denominator to all Twitter users

82:35because they're trying to optimize,

82:37they're purely trying to optimize popularity,

82:39they're purely trying to optimize engagement,

82:41but that's not what I want.

82:42So they should put me in control of some setting

82:46so that I define what's the objective function

82:48that Twitter is going to be following

82:52to show me this content.

82:54And honestly, so this is all about interface design.

82:57And it's not realistic to give users control

83:00over a bunch of knobs that define algorithm.

83:03Instead, we should purely put them in charge

83:06of defining the objective function.

83:09Like let the user tell us what they want to achieve,

83:13how they want this algorithm to impact their lives.

83:15- So do you think it is that,

83:16or do they provide individual article

83:18by article reward structure where you give a signal,

83:21I'm glad I saw this, or I'm glad I didn't.

83:24- So like a Spotify type feedback mechanism,

83:28it works to some extent.

83:29I'm kind of skeptical about it

83:31because the only way the algorithm,

83:34the algorithm will attempt to relate your choices

83:39with the choices of everyone else, which might, you know,

83:43if you have an average profile that works fine,

83:45I'm sure Spotify accommodations work fine

83:47if you just like mainstream stuff.

83:49If you don't, it can be, it's not optimal at all, actually.

83:53- It'll be an inefficient search

83:56for the part of the Spotify world that represents you.

84:00- So it's a tough problem,

84:02but do note that even a feedback system

84:07like what Spotify has does not give me control

84:10over what the algorithm is trying to optimize for.

84:14- Well, public awareness, which is what we're doing now,

84:19is a good place to start.

84:21Do you have concerns about long-term existential threats

84:25of artificial intelligence?

84:27- Well, as I was saying,

84:31our world is increasingly made of information.

84:33AI algorithms are increasingly gonna be our interface

84:36to this world of information,

84:37and somebody will be in control of these algorithms.

84:41And that puts us in any kind of a bad situation, right?

84:45It has risks.

84:46It has risks coming from potentially large companies

84:52wanting to optimize their own goals,

84:54maybe profits, maybe something else.

84:57Also from governments who might want to use these algorithms

85:01as a means of control of the population.

85:04- Do you think there's existential threat

85:06that could arise from that?

85:07- So existential threat.

§10Transcript · 1:25:10–1:34:31

85:10So maybe you're referring to the singularity narrative

85:14where robots just take over.

85:16- Well, I don't, not Terminator robots,

85:19and I don't believe it has to be a singularity.

85:21We're just talking to, just like you said,

85:25the algorithm controlling masses of populations.

85:28The existential threat being,

85:31hurt ourselves much like a nuclear war would hurt ourselves.

85:37That kind of thing.

85:38I don't think that requires a singularity,

85:40that requires a loss of control over AI algorithms.

85:43- Yes.

85:44So I do agree there are concerning trends.

85:47Honestly, I wouldn't want to make any long-term predictions.

85:52I don't think today we really have the capability

85:56to see what the dangers of AI are gonna be in 50 years,

86:00in a hundred years.

86:02I do see that we are already faced with concrete

86:07and present dangers surrounding the negative side effects

86:12of content recombination systems, of newsfeed algorithms,

86:15concerning algorithmic bias as well.

86:18So we are delegating more and more decision processes

86:24to algorithms.

86:25Some of those algorithms are uncrafted,

86:27some are learned from data,

86:30but we are delegating control.

86:32Sometimes it's a good thing, sometimes not so much.

86:37And there is in general very little supervision

86:40of this process, right?

86:41So we are still in this period of very fast change,

86:46even chaos, where society is restructuring itself,

86:51turning into an information society,

86:53which itself is turning into an increasingly automated

86:57information processing society.

86:59And well, yeah, I think the best we can do today

87:03is try to raise awareness around some of these issues.

87:06And I think we're actually making good progress.

87:08If you look at algorithmic bias, for instance,

87:11three years ago, even two years ago,

87:14very, very few people were talking about it.

87:17And now all the big companies are talking about it.

87:20They are often not in a very serious way,

87:22but at least it is part of the public discourse.

87:24You see people in Congress talking about it.

87:26And it all started from raising awareness.

87:31- Right.

87:32So in terms of alignment problem,

87:36trying to teach as we allow algorithms,

87:39just even recommender systems on Twitter,

87:41encoding human values and morals,

87:47decisions that touch on ethics,

87:50how hard do you think that problem is?

87:52How do we have loss functions in neural networks

87:57that have some component,

87:58some fuzzy components of human morals?

88:01- Well, I think this is really all about

88:04objective function engineering,

88:06which is probably going to be increasingly

88:08a topic of concern in the future.

88:10Like for now, we're just using very naive loss functions

88:14because the hard part is not actually

88:16what you're trying to minimize, it's everything else.

88:19But as the everything else

88:20is going to be increasingly automated,

88:22we're going to be focusing our human attention

88:27on increasingly high level components.

88:30Like what's actually driving the whole learning system,

88:32like the objective function.

88:33So loss function engineering is going to be,

88:36loss function engineer is probably going to be

88:38a job title in the future.

88:40- And then the tooling you're creating with Keras

88:42essentially takes care of all the details underneath.

88:47And basically the human expert is needed for exactly that.

88:52- That's the idea.

88:53Keras is the interface between the data you're collecting

88:57and the business goals.

88:59And your job as an engineer is going to be to express

89:02your business goals and your understanding of your business

89:05or your product, your system as a kind of loss function

89:09or a kind of set of constraints.

89:11- Does the possibility of creating an AGI system

89:14excite you or scare you?

89:17Or bore you?

89:18- So intelligence can never really be general.

89:22You know, at best it can have some degree of generality

89:24like human intelligence.

89:26It's also always has some specialization

89:29in the same way that human intelligence is specialized

89:31in a certain category of problems,

89:33is specialized in the human experience.

89:35And when people talk about AGI,

89:37I'm never quite sure if they're talking about

89:39very, very smart AI, so smart that it's even smarter

89:44than humans, or they're talking about human-like

89:47intelligence, because these are different things.

89:49- Let's say, presumably I'm impressing you today

89:53with my humanness.

89:54So imagine that I was in fact a robot.

89:58So what does that mean?

90:00I'm impressing you with natural language processing.

90:04Maybe if you weren't able to see me,

90:06maybe this is a phone call.

90:07So that kind of system.

90:09- Okay, so-- - Companion.

90:11- So that's very much about building human-like AI.

90:15And you're asking me, you know,

90:16is this an exciting perspective?

90:18- Yes.

90:19- I think so, yes.

90:20Not so much because of what artificial

90:26human-like intelligence could do,

90:28but, you know, from an intellectual perspective,

90:30I think if you could build truly human-like intelligence,

90:34that means you could actually understand human intelligence,

90:37which is fascinating, right?

90:39Human-like intelligence is gonna require emotions,

90:42it's gonna require consciousness,

90:44which is not things that would normally be required

90:47by an intelligent system.

90:49If you look at, you know, we were mentioning earlier,

90:51like science as superhuman problem-solving agent or system,

90:56it does not have consciousness, it doesn't have emotions.

91:02In general, so emotions, I see consciousness

91:05as being on the same spectrum as emotions.

91:07It is a component of the subjective experience

91:12that is meant very much to guide behavior generation, right?

91:17It's meant to guide your behavior.

91:20In general, human intelligence and animal intelligence

91:24has evolved for the purpose of behavior generation, right?

91:29Including in a social context,

91:30so that's why we actually need emotions,

91:32that's why we need consciousness.

91:34An artificial intelligence system

91:36developed in a different context may well never need them,

91:39may well never be conscious, like science.

91:43- Well, on that point, I would argue it's possible

91:46to imagine that there's echoes of consciousness in science

91:51when viewed as an organism, that science is consciousness.

91:54- So, I mean, how would you go about testing this hypothesis?

91:59How do you probe the subjective experience

92:02of an abstract system like science?

92:06- Well, the point of probing any subjective experience

92:09is impossible, 'cause I'm not science, I'm Lex.

92:13So I can't probe another entity's,

92:16it's no more than bacteria on my skin.

92:20- You're Lex, I can ask you questions

92:22about your subjective experience and you can answer me,

92:25and that's how I know you're conscious.

92:27- Yes, but that's because we speak the same language.

92:31You perhaps, we have to speak the language of science

92:35in order to ask it. - Honestly,

92:35I don't think consciousness, just like emotions

92:38of pain and pleasure, is not something that inevitably arises

92:43from any sort of sufficiently

92:46intelligent information processing.

92:48It is a feature of the mind,

92:49and if you've not implemented it explicitly,

92:52it is not there.

92:54- So you think it's an emergent feature

92:56of a particular architecture.

92:59So do you think--

93:00- It's a feature in the same sense.

93:02So again, the subjective experience

93:04is all about guiding behavior.

93:07If the problems you're trying to solve

93:11don't really involve embodied agents,

93:15maybe in a social context, generating behavior

93:18and pursuing goals like this.

93:19And if you look at science,

93:20that's not really what's happening, even though it is.

93:23It is a form of artificial AI, artificial intelligence,

93:28in the sense that it is solving problems,

93:30it is accumulating knowledge,

93:32accumulating solutions and so on.

93:34So if you're not explicitly implementing

93:38a subjective experience,

93:39implementing certain emotions

93:42and implementing consciousness,

93:44it's not gonna just spontaneously emerge.

93:47- Yeah, but so for a system like,

93:50human-like intelligent system that has consciousness,

93:53do you think it needs to have a body?

93:56- Yes, definitely.

93:56I mean, it doesn't have to be a physical body, right?

93:59And there's not that much difference

94:01between a realistic simulation and the real world.

94:03- Oh, so there has to be something

94:04you have to preserve kind of thing.

94:06- Yes, but human-like intelligence

94:08can only arise in a human-like context.

94:11Intelligence in the start.

94:12- In other humans, in order for you to demonstrate

94:16that you have human-like intelligence essentially.

94:19- Yes.

94:20- So what kind of test and demonstration

94:25would be sufficient for you

94:28to demonstrate human-like intelligence?

94:31- Yeah.

94:31- I just out of curiosity,

§11Transcript · 1:34:32–1:43:56

94:32you've talked about in terms of theorem proving

94:35and program synthesis,

94:37I think you've written about

94:38that there's no good benchmarks for this.

94:40- Yeah.

94:41- That's one of the problems.

94:42So let's talk program synthesis.

94:46So what do you imagine is a good,

94:48I think it's related questions for human-like intelligence

94:51and for program synthesis.

94:53What's a good benchmark for either or both?

94:56- Right, so I mean, you're actually asking two questions,

94:59which is one is about qualifying intelligence

95:02and comparing the intelligence of an artificial system

95:07to the intelligence for human.

95:08And the other is about degree to which

95:12this intelligence is human-like.

95:13It's actually two different questions.

95:15So if you look, you mentioned earlier the Turing test.

95:19- Right.

95:20- Well, I actually don't like the Turing test

95:21because it's very lazy.

95:23It's all about completely bypassing the problem

95:26of defining and measuring intelligence.

95:28- Right.

95:29- And instead delegating to a human judge

95:32or a panel of human judges.

95:34So it's a total cop out, right?

95:37If you want to measure how human-like an agent is,

95:43I think you have to make it interact with other humans.

95:47Maybe it's not necessarily a good idea

95:49to have these other humans be the judges.

95:53Maybe you should just observe behavior

95:56and compare it to what a human would actually have done.

95:59When it comes to measuring how smart,

96:03how clever an agent is and comparing that

96:06to the degree of human intelligence.

96:11So we're already talking about two things, right?

96:13The degree, kind of like the magnitude of an intelligence

96:17and its direction, right?

96:20Like the norm of a vector and its direction.

96:23And the direction is like human likeness

96:26and the magnitude, the norm is intelligence.

96:31You could call it intelligence, right?

96:34- So the direction, your sense, the space of directions

96:38that are human-like is very narrow.

96:41- Yeah.

96:42So the way you would measure the magnitude of intelligence

96:48in a system in a way that also enables you to compare it

96:51to that of a human.

96:54Well, if you look at different benchmarks

96:58for intelligence today, they're all too focused on skill

97:03at a given task.

97:04That's skill at playing chess, skill at playing Go,

97:07skill at playing Dota.

97:09And I think that's not the right way to go about it

97:14because you can always be too human at one specific task.

97:19The reason why our skill at playing Go or juggling

97:23or anything is impressive is because we are expressing

97:26this skill within a certain set of constraints.

97:29If you remove the constraints, the constraints

97:32that we have one lifetime, that we have this body and so on,

97:35if you remove the context, if you have unlimited string data,

97:40if you can have access to, for instance,

97:41if you look at juggling, if you have no restriction

97:44on the hardware, then achieving arbitrary levels of skill

97:48is not very interesting and says nothing about

97:51the amount of intelligence you've achieved.

97:53So if you want to measure intelligence,

97:55you need to rigorously define what intelligence is,

97:59which in itself, it's a very challenging problem.

98:04- And do you think that's possible?

98:05- To define intelligence, yes, absolutely.

98:07I mean, you can provide, many people have provided

98:10some definition, I have my own definition.

98:13- Where does your definition begin if it doesn't end?

98:16- Well, I think intelligence is essentially the efficiency

98:21with which you turn experience into generalizable programs.

98:27So what that means is it's the efficiency

98:32with which you turn a sampling of experience space

98:36into the ability to process a larger chunk

98:41of experience space.

98:46So measuring skill can be one proxy,

98:51because many different tasks can be one proxy

98:53for measuring intelligence,

98:54but if you want to only measure skill,

98:57you should control for two things.

98:58You should control for the amount of experience

99:03that your system has and the priors that your system has.

99:08But if you control, if you look at two agents

99:12and you give them the same priors

99:13and you give them the same amount of experience,

99:17there is one of the agents that is going to learn programs,

99:22representations, something, a model,

99:24that will perform well on the larger chunk

99:27of experience space than the other,

99:29and that is the smaller agent.

99:32- Yeah, so if you fix the experience,

99:35which generate better programs,

99:37better meaning more generalizable.

99:39That's really interesting.

99:40That's a very nice, clean definition of--

99:42- Oh, by the way, in this definition,

99:45it is already very obvious

99:47that intelligence has to be specialized,

99:49because you're talking about experience space

99:51and you're talking about segments of experience space.

99:54You're talking about priors

99:55and you're talking about experience.

99:57All of these things define the context

100:00in which intelligence emerges.

100:02And you can never look at the totality

100:07of experience space, right?

100:09So intelligence has to be specialized.

100:12- But it can be sufficiently large,

100:13the experience space, even though it's specialized.

100:16There's a certain point when the experience space

100:18is large enough to where it might as well be general.

100:22It feels general, it looks general.

100:23- Sure, I mean, it's very relative.

100:25Like, for instance, many people would say

100:27human intelligence is general.

100:29In fact, it is quite specialized.

100:31You know, we can definitely build systems

100:34that start from the same innate priors

100:37as what humans have at birth,

100:39because we already understand fairly well

100:42what sort of priors we have as humans.

100:44Like, many people have worked on this problem,

100:46most notably Elisabeth Spelke from Harvard,

100:51I don't know if you know her.

100:52She's worked a lot on what she calls core knowledge,

100:56and it is very much about trying to determine

100:59and describe what priors we are born with.

101:02- Like language skills and so on, all that kind of stuff.

101:04- Exactly.

101:05So we have some pretty good understanding

101:09of what priors we are born with.

101:11So we could, so I've actually been working on a benchmark

101:16for the past couple of years, you know, on and off.

101:18I hope to be able to release it at some point.

101:21The idea is to measure the intelligence of systems

101:26by considering for priors,

101:28considering for amount of experience,

101:30and by assuming the same priors

101:33as what humans are born with,

101:34so that you can actually compare these scores

101:37to human intelligence,

101:39and you can actually have humans pass the same test

101:42in a way that's fair.

101:44And so importantly, such a benchmark

101:48should be such that

101:49any amount of practicing does not increase your score.

101:56So try to picture a game

101:58where no matter how much you play this game,

102:00that does not change your skill at the game.

102:05Can you picture that?

102:06- As a person who deeply appreciates practice,

102:11I cannot actually.

102:12I cannot, I cannot, I, yeah.

102:16- There's actually a very simple trick.

102:18So in order to come up with a task,

102:21so the only thing you can measure is skill at a task.

102:24- Yes.

102:25- So these tasks are gonna involve priors.

102:27- Yeah.

102:28- The trick is to know what they are,

102:30and to describe that.

102:32And then you make sure that this is the same set of priors

102:34as what humans start with.

102:36So you create a task that assumes these priors,

102:38that exactly documents these priors,

102:40so that the priors are made explicit,

102:42and there are no other priors involved.

102:44And then you generate a certain number of samples

102:49in experience space for this task, right?

102:52And this, for one task,

102:54assuming that the task is new for the agent passing it,

102:59that's one test of this definition of intelligence

103:04that we set up.

103:07And now you can scale that to many different tasks,

103:09that all, you know,

103:10each task should be new to the agent passing it, right?

103:14And also should be human, yeah,

103:15human interpretable and understandable,

103:17so that you can actually have a human pass the same test,

103:19and then you can compare the score of your machine

103:21and the score of your human.

103:22- Which could be a lot,

103:23you could even start a task like MNIST,

103:26just as long as you start with the same set of priors.

103:28- Yeah, so the problem with MNIST,

103:30humans are already trying to recognize digits, right?

103:34And, but let's say we're considering objects

103:39that are not digits, some completely arbitrary patterns.

103:44Well, humans already come with visual priors

103:47about how to process that.

103:50So in order to make the game fair,

103:51you would have to isolate these priors and describe them,

103:56and then express them as computational rules.

§12Transcript · 1:43:58–1:53:17

103:58- Having worked a lot with vision science people,

104:01that's exceptionally difficult.

104:03A lot of progress has been made,

104:04there's been a lot of good tests,

104:05and basically reducing all of human vision

104:08into some good priors.

104:09I mean, we're still probably far away from that perfectly,

104:12but as a start for a benchmark,

104:14that's an exciting possibility.

104:15- Yeah, so Elisabeth Belke actually lists

104:20objectness as one of the core knowledge priors.

104:24- Objectness, cool.

104:25- Objectness, yeah.

104:27So we have priors about objectness,

104:29like about the visual space, about time,

104:31about agents, about goal-oriented behavior.

104:34We have many different priors,

104:37but what's interesting is that,

104:38sure, we have this pretty diverse and rich set of priors,

104:44but it's also not that diverse, right?

104:48We are not born into this world

104:50with a ton of knowledge about the world,

104:52with only a small set of

104:55core knowledge.

104:59- Yeah, sorry, do you have a sense of how

105:02it feels to us humans that that set is not that large?

105:07But just even the nature of time

105:09that we kind of integrate pretty effectively

105:11through all of our perception, all of our reasoning,

105:14maybe how, you know,

105:16do you have a sense of how easy it is

105:18to encode those priors?

105:19Maybe it requires building a universe

105:23and then the human brain in order to encode those priors.

105:27Or do you have a hope that it can be listed

105:29like in axiomatic sense?

105:30- I don't think so.

105:31You have to keep in mind that any knowledge

105:33about the world that we are born with

105:36is something that has to have been encoded

105:39into our DNA by evolution at some point.

105:43And DNA is a very, very low bandwidth medium.

105:47Like it's extremely long and expensive

105:50to encode anything into DNA,

105:52because first of all,

105:53you need some sort of evolutionary pressure

105:57to guide this writing process.

105:59And then, you know,

106:01the higher level of information you're trying to write,

106:03the longer it's going to take.

106:05And the thing in the environment

106:11that you're trying to encode knowledge about

106:13has to be stable over this duration.

106:17So you can only encode into DNA things

106:19that constitute an evolutionary advantage.

106:22So this is actually a very small subset

106:25of all possible knowledge about the world.

106:27You can only encode things that are stable,

106:31that are true over very, very long periods of time,

106:33typically millions of years.

106:35For instance, we might have some visual prior

106:37about the shape of snakes, right?

106:40But all the, what makes a face,

106:43what's the difference between a face and an ant face?

106:46But consider this interesting question.

106:49Do we have any innate sense of the visual difference

106:54between a male face and a female face?

106:58What do you think?

106:59For a human, I mean.

107:01- I would have to look back into evolutionary history

107:03when the gender is emerged, but yeah, most.

107:08I mean, the faces of humans are quite different

107:10from the faces of great apes, great apes, right?

107:13- Yeah, that's interesting, but yeah.

107:17- You couldn't tell the face of a female chimpanzee

107:21from the face of a male chimpanzee, probably.

107:23- Yeah, and I don't think most humans have all that ability.

107:26- So we do have innate knowledge of what makes a face,

107:30but it's actually impossible for us to have any DNA

107:34encoding knowledge of the difference

107:36between a female human face and a male human face,

107:40because that knowledge, that information

107:44came up into the world actually very recently.

107:50If you look at the slowness of the process

107:54of encoding knowledge into DNA.

107:56- Yeah, so that's interesting.

107:57That's a really powerful argument.

107:59The DNA is a low bandwidth,

108:00and it takes a long time to encode.

108:02That naturally creates a very efficient encoding.

108:05- And one important consequence of this is that,

108:09so yes, we are born into this world

108:12with a bunch of knowledge,

108:13sometimes a high level knowledge about the world,

108:15like the shape, the rough shape of a snake,

108:18of the rough shape of face.

108:20But importantly, because this knowledge

108:22takes so long to write,

108:24almost all of this innate knowledge is shared

108:29with our cousins, with great apes, right?

108:33So it is not actually this innate knowledge

108:35that makes us special.

108:37- But to throw it right back at you

108:39from the earlier on in our discussion,

108:42that encoding might also include

108:46the entirety of the environment of Earth.

108:49- To some extent, so it can include things

108:53that are important to survival and production,

108:56so for which there is some evolutionary pressure,

108:59and things that are stable, constant,

109:01over very, very, very long time periods.

109:04And honestly, it's not that much information.

109:07There's also, besides the bandwidths constraint

109:10and the constraints of the writing process,

109:15there's also memory constraints.

109:18Like DNA, the part of DNA that deals with the human brain,

109:22it's actually fairly small.

109:23It's like, you know, on the order of megabytes, right?

109:26There's not that much high level knowledge

109:28about the world you can encode.

109:31- That's quite brilliant and hopeful for a benchmark

109:35of, that you're referring to, of encoding priors.

109:38I actually look forward to, I'm skeptical

109:41whether you can do it in the next couple of years,

109:43but hopefully.

109:44- I've been working on it.

109:45So honestly, it's a very simple benchmark,

109:47and it's not like a big breakthrough or anything.

109:49It's more like a fun side project, right?

109:52- But these fun, so is ImageNet.

109:56- These fun side projects could launch entire groups

110:00of efforts towards creating reasoning systems and so on.

110:05And I think-

110:06- Yeah, that's the goal.

110:06It's trying to measure strong generalization,

110:09to measure the strength of abstraction in our minds,

110:12well, in our minds and in artificial intelligence.

110:17- And if there's anything true about this science organism,

110:20it's individual cells love competition.

110:24So, and benchmarks encourage competition.

110:26So that's an exciting possibility.

110:29If you, do you think an AI winter is coming?

110:33And how do we prevent it?

110:35- Not really.

110:36So an AI winter is something that would occur

110:39when there's a big mismatch

110:41between how we are selling the capabilities of AI

110:44and the actual capabilities of AI.

110:47And today, so deep learning is creating a lot of value,

110:50and it will keep creating a lot of value in the sense that

110:54these models are applicable to a very wide range of problems

110:58that are relevant today.

111:00And we are only just getting started

111:02with applying algorithms to every problem

111:05that could be solving.

111:06So deep learning will keep creating a lot of value

111:09for the time being.

111:10What's concerning, however, is that there's a lot of hype

111:14around deep learning and around AI.

111:16There are lots of people are overselling the capabilities

111:20of these systems, not just the capabilities,

111:22but also overselling the fact that they might be

111:26more or less, you know, brain-like,

111:29like given a kind of a mystical aspect,

111:34these technologies,

111:35and also overselling the pace of progress,

111:39which, you know, it might look fast in the sense that

111:43we have this exponentially increasing number of papers.

111:46But again, that's just a simple consequence of the fact

111:51that we have ever more people coming into the field.

111:54It doesn't mean the progress is actually exponentially fast.

111:57Like, let's say you're trying to raise money

112:00for your startup or your research lab.

112:02You might want to tell, you know,

112:05a grandiose story to investors about how deep learning

112:09is just like the brain and how it can solve

112:11all these incredible problems like self-driving

112:14and robotics and so on.

112:15And maybe you can tell them that the field is progressing

112:18so fast and we are going to have AGI within 15 years

112:21or even 10 years.

112:23And none of this is true.

112:25And every time you're like saying these things

112:30and an investor or, you know, a decision maker believes them,

112:34well, this is like the equivalent of taking on

112:37credit card debt, but for trust, right?

112:42- Yeah.

112:43- And maybe this will, you know,

112:47this will be what enables you to raise a lot of money,

112:50but ultimately you are creating damage.

112:53You are damaging the field.

112:54- So that's the concern is that that debt,

112:57that's what happens with the other AI winters.

112:59Is the concern is you actually tweet about this

113:02with autonomous vehicles, right?

113:04There's almost every single company now have promised

113:07that they will have full autonomous vehicles by 2021, 2022.

113:11- That's a good example of the consequences

113:15of overhyping the capabilities of AI

113:17and the pace of progress.

§13Transcript · 1:53:19–1:59:47

113:19- So, because I work especially a lot recently in this area,

113:23I have a deep concern of what happens

113:25when all of these companies, after I've invested billions,

113:29have a meeting and say, how much did we actually,

113:31first of all, do we have an autonomous vehicle?

113:33The answer will definitely be no.

113:35And second would be, wait a minute,

113:37we've invested one, two, three, $4 billion into this

113:41and we made no profit.

113:43And the reaction to that may be going very hard

113:47in another direction that might impact

113:49even other industries.

113:50- And that's what we call an AI winter

113:52is when there is backlash,

113:53where no one believes any of these promises anymore

113:56because they've turned out to be big lies

113:58the first time around.

113:59And this will definitely happen to some extent

114:03for autonomous vehicles

114:04because the public and decision makers have been convinced

114:08that around 2015, they've been convinced

114:12by these people who are trying to raise money

114:14for their startups and so on,

114:16that L5 driving was coming in maybe 2016,

114:20maybe 2017, maybe 2018.

114:22Now in 2019, we're still waiting for it.

114:26And so I don't believe we are going to have

114:30a full-on AI winter because we have these technologies

114:33that are producing a tremendous amount of real value.

114:36- Yeah.

114:37- But there is also too much hype.

114:39So there will be some backlash,

114:41especially there will be backlash.

114:43So, you know, some startups are trying to sell

114:47the dream of AGI, right?

114:49And the fact that AGI is going to create infinite value,

114:53like AGI is like a free lunch.

114:55Like if you can develop an AI system

114:58that passes a certain threshold of IQ or something,

115:02then suddenly you have infinite value.

115:04And well, there are actually lots of investors

115:09buying into this idea.

115:11And, you know, they will wait maybe 10, 15 years

115:15and nothing will happen.

115:17And the next time around, well, maybe there will be

115:21a new generation of investors.

115:22No one will care.

115:23You know, human memory is fairly short after all.

115:26- I don't know about you, but because I've spoken about AGI

115:31sometimes poetically, like I get a lot of emails from people

115:35giving me, they're usually like large manifestos

115:39of they say to me that they have created an AGI system

115:46or they know how to do it.

115:47And there's a long write-up of how to do it.

115:48- I get a lot of these emails, yeah.

115:50- They're a little bit, feel like it's generated

115:53by an AI system actually, but there's usually no diagram.

115:57- Maybe that's recursively self-improving AI.

116:00- Exactly.

116:01- It's you have a transformer generating

116:03crank papers about AGI.

116:06- So the question is about, because you've been such a good,

116:09you have a good radar for crank papers.

116:12How do we know they're not onto something?

116:16How do I, so when you start to talk about AGI

116:22or anything like the reasoning benchmarks and so on,

116:24so something that doesn't have a benchmark,

116:27it's really difficult to know.

116:28I mean, I talked to Jeff Hawkins,

116:31who's really looking at neuroscience approaches to how,

116:35and there's some, there's echoes of really interesting ideas

116:40in at least Jeff's case, which he's showing.

116:42How do you usually think about this?

116:45Like preventing yourself from being too narrow-minded

116:49and elitist about deep learning.

116:52It has to work on these particular benchmarks,

116:55otherwise it's trash.

116:56- Well, you know, the thing is intelligence

117:02does not exist in the abstract.

117:05Intelligence has to be applied.

117:07So if you don't have a benchmark,

117:08if you're not doing an improvement on some benchmark,

117:10maybe it's a new benchmark, right?

117:12Maybe it's not something we've been looking at before,

117:14but you do need a problem that you're trying to solve.

117:17You're not going to come up with a solution

117:19without a problem.

117:19- So you, general intelligence, I mean,

117:23you've clearly highlighted generalization.

117:25If you want to claim that you have an intelligence system,

117:30it should come with a benchmark.

117:31- It should, yes.

117:32It should display capabilities of some kind.

117:35It should show that it can create some form of value,

117:40even if it's a very artificial form of value.

117:42And that's also the reason why you don't actually

117:45need to care about telling which papers

117:48have actually some hidden potential and which do not.

117:52Because if there is a new technique

117:56that's actually creating value,

117:57you know, this is going to be brought to light very quickly

118:00because it's actually making a difference.

118:02So it's the difference between something that's ineffectual

118:04and something that is actually useful.

118:08And ultimately usefulness is our guide,

118:11not just in this field,

118:12but if you look at science in general,

118:14maybe there are many, many people over the years

118:16that have had some really interesting theories

118:19of everything, but they were just completely useless.

118:22And you don't actually need to tell the interesting theories

118:26from the useless theories.

118:28All you need is to see, you know,

118:30is this actually having an effect on something else?

118:33You know, is this actually useful?

118:35Is this making an impact or not?

118:36- That's beautifully put.

118:38I mean, the same applies to quantum mechanics,

118:41to a string theory, to the holographic principle.

118:43- Like we are doing deep learning because it works.

118:45You know, that's like before it started working,

118:48people, you know, considered people working

118:50on neural networks as cranks very much.

118:53Like, you know, no one was working on this anymore.

118:56And now it's working, which is what makes it valuable.

118:59It's not about being right, right?

119:01It's about being effective.

119:02- And nevertheless, the individual entities

119:04of the scientific mechanism,

119:06just like Yoshua Banjo, Yan Likun,

119:09while being called cranks, stuck with it, right?

119:12- Yeah.

119:13- And so us individual agents,

119:15even if everyone's laughing at us,

119:17just stick with it because--

119:18- If you believe you have something,

119:20you should stick with it and see it through.

119:21- That's a beautiful, inspirational message to end on.

119:25Francois, thank you so much for talking today.

119:27That was amazing.

119:28- Thank you.

119:29(upbeat music)

119:29(upbeat music)

119:47(upbeat music)

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