Haunting and frighteningly timely short essay. This particular part jumped out (not least because the first sentence is highlighted):

The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt. Even those of the intelligent who believe that they have a nostrum are too individualistic to combine with other intelligent men from whom they differ on minor points.

Around the same time (1930), Sigmund Freud articulated the concept of "the narcissism of small differences" in his book Civilization and its Discontents, a concept that is endlessly useful in understanding how otherwise like-minded people tend to tear themselves apart. A related concept in software development is "bikeshedding".