“He had acquired his belief not by honestly earning it in patient investigation, but by stifling his doubts. And although in the end he may have felt so sure about it that he could not think otherwise, yet inasmuch as he had knowingly and willingly worked himself into that frame of mind, he must be held responsible for it.”

Ron Bloom points us to this wonderful article, “The Ethics of Belief,” by the mathematician William Clifford, also known for Clifford algebras. The article is related to some things I’ve written about evidence vs. truth (see here and here) but much more beautifully put. Here’s how it begins:

A shipowner was about to send to sea an emigrant-ship. He knew that she was old, and not overwell built at the first; that she had seen many seas and climes, and often had needed repairs. Doubts had been suggested to him that possibly she was not seaworthy. These doubts preyed upon his mind, and made him unhappy; he thought that perhaps he ought to have her thoroughly overhauled and refitted, even though this should put him to great expense. Before the ship sailed, however, he succeeded in overcoming these melancholy reflections. He said to himself that she had gone safely through so many voyages and weathered so many storms that it was idle to suppose she would not come safely home from this trip also. He would put his trust in Providence, which could hardly fail to protect all these unhappy families that were leaving their fatherland to seek for better times elsewhere. He would dismiss from his mind all ungenerous suspicions about the honesty of builders and contractors. In such ways he acquired a sincere and comfortable conviction that his vessel was thoroughly safe and seaworthy; he watched her departure with a light heart, and benevolent wishes for the success of the exiles in their strange new home that was to be; and he got his insurance-money when she went down in mid-ocean and told no tales.

What shall we say of him? Surely this, that he was verily guilty of the death of those men. It is admitted that he did sincerely believe in the soundness of his ship; but the sincerity of his conviction can in no wise help him, because he had no right to believe on such evidence as was before him. He had acquired his belief not by honestly earning it in patient investigation, but by stifling his doubts. And although in the end he may have felt so sure about it that he could not think otherwise, yet inasmuch as he had knowingly and willingly worked himself into that frame of mind, he must be held responsible for it.

Clifford’s article is from 1877!

Bloom writes:

One can go over this in two passes. One pass may be read as “moral philosophy.”

But the second pass helps one think a bit about how one ought to make precise the concept of ‘relevance’ in “relevant evidence.”

Specifically (this is remarkably deficient in the Bayesian corpus I find) I would argue that when we say “all probabilities are relative to evidence” and write the symbolic form straightaway P(A|E) we are cheating. We have not faced the fact — I think — that not every “E” has any bearing (“relevance”) one way or another on A and that it is *inadmissible* to combine the symbols because it is so easy to write ’em down. Perhaps one evades the problem by saying, well what do you *think* is the case. Perhaps you might say, “I think that E is irrelevant if P(A|E) = P(A|~E).” But that begs the question: it says in effect that *both* E and ~E can be regarded as “evidence” for A. I argue that easily leads to nonsense. To regard any utterance or claim as “evidence” for any other utterance or claim leads to absurdities. Here for instance:

A = “Water ice of sufficient quantity to maintain a lunar base will be found in the spectral analysis of the plume of the crashed lunar polar orbiter.”

E = If there are martians living on the Moon of Jupiter, Europa, then they celebrate their Martian Christmas by eating Martian toast with Martian jam.

Is E evidence for A? is ~E evidence for A? Is any far-fetched hypothetical evidence for any other hypothetical whatsoever?

Just to provide some “evidence” that I am not being entirely facetious about the Lunar orbiter; I attach also a link to now much superannuated item concerning that very intricate “experiment” — I believe in the end there was some spectral evidence turned up consistent with something like a teaspoon’s worth of water-ice per 25 square Km.

P.S. Just to make the connection super-clear, I’d say that Clifford’s characterization, “He had acquired his belief not by honestly earning it in patient investigation, but by stifling his doubts. And although in the end he may have felt so sure about it that he could not think otherwise, yet inasmuch as he had knowingly and willingly worked himself into that frame of mind, he must be held responsible for it,” is an excellent description of those Harvard professors who notoriously endorsed the statement, “the replication rate in psychology is quite high—indeed, it is statistically indistinguishable from 100%.” Also a good match to those Columbia administrators who signed off on those U.S. News numbers. In neither case did a ship go down; it’s the same philosophical principle but lower stakes. Just millions of dollars involved, no lives lost.

As Isaac Asimov put it, “A robot may not injure a human being or, through inaction, allow a human being to come to harm.” Sometimes that inaction is pretty damn active, when a shipowner or a scientific researcher or a university administrator puts in some extra effort to avoid looking at some pretty clear criticisms.