Thiel's question

“What important truth do very few people agree with you on?” - Peter Thiel 

 His own answer:

This question sounds easy because it’s straightforward. Actually, it’s very hard to answer. It’s intellectually difficult because the knowledge that everyone is taught in school is by definition agreed upon. And it’s psychologically difficult because anyone trying to answer must say something she knows to be unpopular. Brilliant thinking is rare, but courage is in even shorter supply than genius.

How would I answer this question?

Here is a start.

Human beings are not perfectible. At least on this side of heaven. 

And that is...a feature, not a bug.