Jocko Willink: Most Replayed Moment: Your Excuses Will Destroy You, To Be Disciplined Is To Be Free!

The conversation opens with the host's surprise that the guest applied to become a Navy SEAL at 19. Asked the "very dumb question" of what a SEAL actually is, the guest compares the unit to the British SAS and SBS, the two units SEALs are most often compared with. SEALs are the special operations component of the Navy, and the name is an acronym for sea, air and land. Sea means diving. Air means parachuting and rappelling. Land means conducting land warfare operations. The job combines all three.

The host had assumed that elite units like the SEALs or the SAS only recruit people with 10 or 20 years of established military service. The guest corrects this from his own experience. He joined the Navy at 18 on a contract that sent him to SEAL training, which took a year, so he was 19 when he finished. He knows people debate whether more experienced candidates are better. He takes the other side: he "loved the fact that I was basically raised in the SEAL teams," and calls it "an awesome way to grow up" while learning the trade he wanted.

He backs up how rare his path was with approximate figures. He says about 20 percent of people make it through SEAL training, and for people under 20 that falls to about 5 percent. He presents both numbers as rough estimates ("about"), not official statistics.

Asked what the training is ultimately testing, the guest sums it up as one question: "Will you keep going in the face of whatever?" The host brings up Hell Week, and the guest gives its history. It was originally meant to simulate combat. During World War II, the designers packed as much combat simulation as they could into a compressed schedule so they could quickly produce frogmen to send overseas. Today that compression comes to about five and a half days with no sleep, plenty of physical activity, stress and pain, and many people quit.

Asked how many people quit that week, the guest hedges his answer: "I would say most of the people that quit, probably of, it's probably 80% of the quitters quit in that week." That is an estimate of the share of quitters who leave during Hell Week. It is not the share of all trainees.

He says the training is built to find each candidate's particular weakness and press on it. His examples include a strong swimmer with good upper-body strength who is a slow runner, a fast runner who swims badly, someone who can't handle the cold, someone who hates carrying the boat on their head, and someone with a bad temper. In his words, the instructors will find that weakness "and they're going to pick at that thing to either make you come out the other side or make you quit."