Shaving Skeptically

Skeptics seem to have a fascination with sharp metaphorical objects. Most people who have dealt with skeptical issues for any appreciable amount of time are probably familiar with Occam’s Razor (but if not, there’s a great SGU 5×5 Podcast on the issue, here). Today I want to talk about another one of the blades in the skeptic’s tool belt: Hume’s Razor — also known as the problem of miracles.

David Hume was an 18th century Scottish philosopher, who is well known for his skeptical and empirical contributions to philosophy. In part 10 of An Enquiry Concerning Human Understanding, he tells us why we should be skeptical of miraculous events, be they divine, supernatural, or paranormal.

David Hume
David Hume, the lovable sceptic.
Note: the clean shave.

What is a miracle?

“A miracle may accurately be defined, a transgression of a law of nature by a particular volition of the deity, or by the interposition of some invisible agent” (An Enquiry Concerning Human Understanding, p. 115).

A miracle is, by definition, a violation of the laws of nature. This means that it is always more probable that a miracle did not occur than that a miracle did occur. This is because the laws of nature are only called laws because they are not violated on a regular basis (or ever). Some have criticized this definition of a miracle; however, it’s the only way we can be sure we’re dealing with the real thing. If something doesn’t violate natural laws, then how can a natural explanation ever be ruled out?

Possibility vs. Justified Belief

It’s important to note that Hume’s razor doesn’t explicitly address the question of whether or not miracles are possible (though some may argue that it does), but rather whether or not we are ever justified in our belief that a miracle has occurred. In order to understand this distinction, we must first briefly examine the problem of induction as laid out by Hume.

Earlier on in Enquiry, Hume asks us how do we come to know things — specifically, causal relationships (e.g. how a billiard ball will behave when struck by another billiard ball). Hume argues that the only way we can ever come to predict the way things in the world will behave upon interaction is by extrapolating from past experience. This means that there’s no guarantee that future interactions will continue as they have in the past, since the only way we can reason for the continuity of natural laws is through the same inductive process that gives rise to these laws. This critique of inductive reasoning is what is commonly referred to as Hume’s problem of induction.

However, contrary to what is sometimes argued, Hume was not criticizing induction, but rather just trying to make us understand how it is we actually come to know things. In fact, in part 5 of Enquiry (Sceptical Solution of These Doubts), he argues that even though our knowledge of causal relationships is only justified by induction, we are still able to learn and improve based on inductive observations interpreted in a probabilistic framework (i.e. how consistently certain causes lead to certain effects). Hume’s point was that even though induction leaves us starved for knowledge in the philosophic tradition of the word, it nevertheless allows us to make accurate predictions about future states of the world, even in the absence of metaphysical certainty.

The Problem of Miracles

Because we are limited to inductive reasoning in determining the state of the world, we are left with a serious problem when it comes to the issue of miracles. On one hand, we know from past experience that the laws of nature have always been consistent in the absence of miraculous intervention (which is most of the time). Though this is not an argument for the continuation of these laws into the future, it does mean that there is a very high probability that they will continue into the future. On the other hand, we know that when it comes to the testimony of miracles, people lie, people embellish stories, and people can be mistaken. Therefore, testimony (and even personal experience) is always potentially flawed. This isn’t to say that testimony is always flawed, merely that in the balance of probabilities, incorrect testimony will always be more like than a violation of the laws of nature. Therefore, our belief in the occurrence of a miracle can never be justified, because it’s always more likely that there is an alternative explanation.

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  • Mitchell Gerskup

    Mitchell Gerskup recently graduated from the University of Toronto with a degree in Economics and Philosophy. An avid atheist and skeptic, he has served as the President of the University of Toronto Secular Alliance, helping to promote science, reason and critical thinking around Toronto. He also volunteers with the Centre for Inquiry’s Ontario branch, and currently sits on the CFI’s Committee for the Advancement of Scientific Skepticism. Mitchell is also an accomplished competitive debater, having debated all across Canada. In addition to issues of economics and philosophy, Mitchell is interested in the fields of science and technology.