Error Invincibilis

Theodor Haecker, Journal in the Night (Pantheon, 1950, tr. Dru), #691:

Spiritual blindness differs from physical blindness in this, that it is not conscious. That is the essence of error invincibilis.

Compare Blaise Pascal, Pensees #98 (Krailsheimer tr., p. 55):

How is it that a lame man does not annoy us while a lame mind does? Because a lame man recognizes that we are walking straight, while a lame mind says that it is we who are limping.

Please forgive the following reformulation. Point out to a man that he is crippled, and he won't contradict you, though he might take umbrage at your churlishness. But point out to a man that his thinking is crippled and he is sure to reply, "No! It is your thinking that is crippled."

How is it that a lame man does not annoy us while a lame mind does? Because a lame man recognizes that we are walking straight, while a lame mind says that it is we who are limping.

Please forgive the following reformulation. Point out to a man that he is crippled, and he won't contradict you, though he might take umbrage at your churlishness. But point out to a man that his thinking is crippled and he is sure to reply, "No! It is your thinking that is crippled."