The story is told of a man who becomes convinced that he’s dead.  At first, his family tries to logic:  “Look, you’re walking and breathing and talking.  You can’t possibly be dead!”  Failing that, they referred him to a psychiatrist who tried the same line of reasoning, again to no avail.  The man is eventually committed to a mental institution, still firmly convinced that he is dead, and daily visits with the doctors have no effect on changing his mind.

After some time, a new psychiatrist is assigned his case.  The new doctor has a new idea, and walks his patient through the medical texts to convince the man of one fact:  dead men don’t bleed.  After weeks of poring over the texts and other relevant information, the man concedes the point:  dead men do not bleed.

The doctor then takes a pin and pricks the man’s finger.  As you would expect, a drop of blood begins to well up in the tip of the patient’s finger.  Looking at it, astounded, the man exclaims, “Hey, Doc!  Dead men do bleed!”

How often do you run into people who, in spite of all evidence to the contrary, continue clinging to their own preconceived notions in much the same way as the man who was convinced that he was dead?

Better yet, have you ever found yourself holding tightly to a particular belief long after you have seen sufficient evidence to prove that you’re dead wrong?

The ability to re-examine and modify (or discard) your beliefs in the face of contrary evidence and admit it is perhaps the most important mark of intellectual maturity.

Update, June 2024:

I had some difficulty with my web hosting and had to rebuild the blog. In the process I had to decide what to do with comments that people made on old posts. I had no way to enter and attribute them correctly, and most I didn’t deem sufficiently insightful to duplicate. However …

Michael Covington noted on this entry:

This is actually a rather tricky and difficult area of epistemology. As Quine pointed out (and I call it Quine’s Law), evidence can compel you to revise your beliefs as a set, but it cannot compel you to revise a *particular* belief. You can always revise some other belief(s) instead. It is very hard to pin down good criteria for what is reasonable. Logic itself does not tell you how to strike the right balance.

Michael also provided a link to his own blog, where he describes a possible approach.

You can (or could, in June of 2024) see those comments on the Internet Archive backup of my blog post: