Belief and Evidence

I have just read a story in which the author claimed that a parable, popular among atheists, is not actually true.

The story concerns a meeting between Napoleon Bonaparte and a French astronomer Laplace.

Some background information is useful for understanding this story. In the 1600s, Isaac Newton had published his laws of motion in which, among other things, he explained the orbits of the planets. However, on Newton’s accounts, these orbits were unstable. Each planet exerts a small influence on the others so that, over time, the solar system would fall apart. To solve this problem, Newton said that God intervened to make minor changes in the orbits of planets to keep the solar system stable.

Laplace came along with some new mathematical formulae that showed that the orbits of the planets were stable after all.

The story popular among atheists is that, after Laplace explained his new discoveries to Napoleon, Napoleon asked why God was not mentioned. Laplace’s popular response was, “Sire, I had no need of that hypothesis.”

Daniel Johnson reports in an article titled, “The Hypothetical Atheist” that this exchange probably never took place. Instead, Johnson presented the case that a historian E.T. Bell made up the story, presenting it in his book Men in Mathematics in 1937. Those atheists who are fond of this story have merely accepted on faith that the story was true.

Johnson's so-called scholarship on the issue is questionable. It took me just a few minutes to trace the quote at least to Augustus De Morgan's A Budget of Paradoxes published posthumously from a collection of essays De Morgan wrote. De Morgan died in 1871, suggesting that the quote can be traced significantly further back than Johnson claimed.

The easy availability of this information suggested that Johnson did very little to research this subject, or that he knew the truth of the matter and decided to lie for political purposes. Either way, Johnson shows that he has a caracteristic disregard for truth and is more than happy to promote fictions to obtain political and social ends.

However, for purposes of this post, it does not matter that Johnson's claim is incorrect. My guess is that few (if any) atheists reading Johnson’s article would have been immediately able to refute it, as I was not. This is because few atheists who have come to accept this story as being true actually acquired that belief on the basis of good evidence. Instead, they came to believe the story because they heard it from a position of authority and it was a story that they wanted to believe to be true.

This supports two conclusions that I have been defending regarding the ethics of belief.

The first conclusion I want to support says that a moral obligation to use nothing but reason in the formation of our beliefs is not only unreasonable but hypocritical. None of us have the time and resources to hold all of our beliefs up to rational scrutiny. Instead, we have to rely on quick but fallible ‘rules of thumb’ for our beliefs – such as the rule to trust people in authority, and to accept as true those propositions that fit into an overall world view. Even the proponents of pure reason, we will discover, need to use quick and fallible rules of thumb from time to time.

The second conclusion that I want to draw comes from the observation that most atheists, I suspect, who believed this story will react to this report much as I did. Once exposed to the idea that the original story was false, they will immediately suspend belief and wait for confirmation. I doubt that any atheists are going to start clamoring for the head of those who dare question the literal truth of the Laplace story or accuse those who spread the story as blasphemy. Nor are they going to campaign that the story much be taught in its original version, and taught as if true, because doing otherwise will weaken the population’s moral commitment to science and reason.

In other words, though there is no prohibition in using quick rules of thumb in forming our beliefs, evidence still matters where it can be found. Precisely because we tend to form our beliefs on the fly, we have no good reason to hold firmly onto them when conflicting evidence comes to light.

Even here, I am going to assert, many rationalists will continue to hold on to a belief far longer than the strict adherence to reason would allow, even when reason comes into play. Once an individual becomes psychologically tied to a proposition so that he identifies with it, then that proposition becomes more difficult to surrender, even in the face conflicting evidence. This is not a problem that is unique to the religious, it is a human weakness. It helps to make religion possible, but religion is not the only bundle of false propositions that a person can embrace on the basis of insufficient evidence.

I will put my own belief in desire utilitarianism in this category. Now that I have come to identify with this set of propositions, I worry that it will take more than the standard set of evidence to the contrary to dissuade me as to the theory’s truth. This is not because I have decided to embrace the theory in complete disregard for any and all evidence that might be brought against it. Rather, it is because this psychological investment will block my ability to see evidence against it as evidence. I am more inclined to dismiss as unsound that which is logically sound, and to embrace that which is logically unsound, if it proves consistent with desire utilitarianism.

Now, there is one last moral principle that I want to apply to this discussion. Even though it is natural for an individual to cling to a belief that they have come to identify with, this does not make it right. The naturalness of a desire is not a measure of its merit. Its merit depends entirely on its tendency to fulfill or thwart other desires. The habit of holding onto beliefs far longer than the evidence would allow is a habit that tends to thwart desires. This, combined by the fact that condemnation can weaken this natural desire-thwarting tendency, makes it a fit target for moral condemnation.

My confession that I may hold onto desire utilitarianism longer than reason would allow is not an argument that it is permissible to do so. It is an argument that I may suffer from a moral failing. If I were the one holding onto this belief while it is no longer reasonable to do so, then I could be legitimately condemned for my stubbornness.

This, of course, assumes that I am holding onto desire utilitarianism longer than reason would permit, which (as far as I can tell) has yet to be demonstrated.

So, here are three moral conclusions that I hope the LaFavore story sheds some light on.

(1) There is no moral crime in using quick rules of thumb to forming beliefs – we must do so in order to function efficiently.

(2) Beliefs that come from these rules of thumb should be dropped whenever an exposure to reason suggests that they are false. Rules of thumb are notoriously fallible.

(3) We also have a tendency to hold onto beliefs longer than a strict view of reason will allow. The naturalness of this tendency does not make it right.