The Sad Case of the Blind Logician

Once upon a time there was a logician who imagined that his ability to reason logically was without error, and that he could reliably identify, diagnose, and report errors in logic by his erstwhile correspondents. He also demanded evidence to support the premises upon which logical arguments were constructed. But curiously enough, this otherwise self-professed logician was blind. Alas, he could not observe and interpret visual evidence with his own faculties; he literally could neither see the evidence nor reliably interpret its meaning. He was obliged to rely on the reports of others as to what was observed, and the meaning or interpretation of those observations.

One day, late in October, a neighbor set out a Jack-O-Lantern — that being a hollowed out pumpkin shell with a small candle inside. The orange skin of the Jack-O-Lantern thus glowed a lovely orange, as if it were luminescent. I asked the blind logician what could be deduced from the luminescent pumpkin. He replied that since the pumpkin shell obeyed the physics of an isothermal black body radiator, it must be glowing because it is at an incandescant temperature, presumably from an interior heat source that was warming up the pumpkin shell to an incandescent temperature. I asked him how he knew that the pumpkin shell was opaque and not translucent. He replied that, according to Wikipedia, pumpkin shells are opaque, and that he could see no evidence to the contrary. So I showed him evidence to the contrary, but he demurred, saying he was blind and thus could not see or interpret the visual evidence before his non-functional eyes.

I was thus reminded of a quote from John Heywood who, in 1546, said, "There are none so blind as those who will not see. The most deluded people are those who choose to ignore what they already know."