There’s ignorance and there’s stupidity. Stupidity will stubbornly resist any attempt to correct its ignorance.

Stupidity is a more dangerous enemy of the good than malice. One may protest against evil; it can be exposed and, if need be, prevented by use of force. Evil always carries within itself the germ of its own subversion in that it leaves behind in human beings at least a sense of unease.

Against stupidity we are defenseless.

Neither protests nor the use of force accomplish anything here; reasons fall on deaf ears; facts that contradict one’s prejudgment simply need not be believed — in such moments the stupid person even becomes critical — and when facts are irrefutable, they are just pushed aside as inconsequential, as incidental. In all this the stupid person, in contrast to the malicious one, is utterly self-satisfied and, being easily irritated, becomes dangerous by going on the attack.

For that reason, greater caution is called for than with a malicious one. Never again will we try to persuade the stupid person with reasons, for it is senseless and dangerous.

…

If we want to know how to get the better of stupidity, we must seek to understand its nature. This much is certain, that it is in essence not an intellectual defect but a human one. There are human beings who are of remarkably agile intellect yet stupid, and others who are intellectually quite dull yet anything but stupid.

Dietrich Bonhoeffer