What Are The Weirdest Types Of Life? - Carl Zimmer

The episode begins on a paradox. Chris Williamson introduces life as what "illuminates our corner of the universe" and asks Carl Zimmer to define it. Zimmer's answer is that the question is far more contested than everyday usage suggests: the literature contains "There are literally hundreds" of definitions and no agreement on which is right. His comparison is chemistry, where "imagine like in chemistry, people didn't agree on what an atom is" — a scandal there, ordinary here.

Part of the confusion is that one word covers different targets. A physician asking whether a ventilated patient is alive is asking about the end of a person; a naturalist asking whether a snake and a tree share something a rock lacks is asking about a category. Both answers get called life, which is why the arguments never close.

Zimmer describes avoidance rather than ignorance. Asked for a definition, working scientists often shrug: "A lot of them actually don't want to really talk about that at all." A tiger specialist need not know fungi; someone working on one protein need not know anything else. The result is a field defined by an object it rarely specifies.