Profundity is best understood as the quality of leading to a better understanding of situations. The profound statement itself doesn't have to be 100% literally true. "All models are wrong; some models are useful."

#11 counters people's default assumption that imagined pain doesn't hurt, because it's not real. You gain more understanding of people who report imagined pain by assuming it hurts the same (even if it might actually hurt a little less) than by assuming it doesn't hurt at all.

In the book Dune, Paul Atreides' hand is put in a pain-simulating device and he has to demonstrate his humanity by resisting the urge to pull it out or he'll be killed by a cyanide needle in the neck. You can only understand that scene by assuming the simulated pain hurts as much as real pain.