This is obviously why Pride is the worst sin. Refusing to accept that one is limited by reality and that therefore one’s actions purporting to do “good” must be subject to reason is obviously always going to lead to disaster of some sort. You can’t just go around claiming what you are doing is “good” just because you feel like it without any regard to the real consequences. (Well, people do that all the time and it always ends badly.)

As always, Scott Alexander’s pride in his ability to determine the intellectual content of something prevents him from actually understanding the reality of what Lewis is saying. Because Alexander won’t consider the idea that Lewis is smarter than him.