>The problem with trying to reason everything from first principles is that most things didn’t actually came about that way.

This is true for science and rationalism itself. Part of the problem is that "being rational" is a social fashion or fad. Science is immensely useful because it produces real results, but we don't really do it for a rational reason - we do it for reasons of cultural and social pressures.

We would get further with rationalism if we remembered or maybe admitted that we do it for reasons that make sense only in a complex social world.