Do Extraordinary Claims Require Extraordinary Evidence?

Too often people have a parrot-like propensity to be seduced by a catchy saying, hold to it, and assert it repeatedly without thinking seriously about what they’re saying. They remember before they speak, but they don’t think before they speak. And the most astonishing fact is that all too often they really do believe they have said something wise.

Chesterton provided an example when he critiqued the popular exhortation to “believe in yourself” in his classic Orthodoxy. “Thoroughly worldly people never understand even the world,” he said.  “They rely altogether on a few cynical maxims which are not true.” In short, when we get intellectually lazy we tend to lean thoughtlessly on faddish sayings. We speak on autopilot.

This is a human folly, so neither I nor those who believe what I believe are exempt from this inclination. Nonetheless, here I would like to narrow down my critique to one phrase often asserted by naturalists: Extraordinary claims require extraordinary evidence. It's often asserted by skeptics as a brute fact without qualification.

Indeed, the saying has become something of a maxim among modern nonbelievers. Astronomer Carl Sagan popularized the principle, although the idea predates him. French scientist Pierre-Simon Laplace asserted something similar when he wrote, “The weight of evidence for an extraordinary claim must be proportioned to its strangeness.”

In An Enquiry Concerning Human Understanding, skeptical philosopher David Hume wrote, “A wise man . . . proportions his belief to the evidence.” Skeptics have cited this quotation in support of their belief that extraordinary claims require extraordinary evidence, but look closely at what Hume says; or better yet, look at what Hume does not say.

He says a wise man proportions his belief to the evidence, and I couldn’t agree more. He does not say, however, that the wise man proportions his evidence to the belief. Hume is right: it is wise to hold beliefs that are well supported by evidence.

Thus we return to our chief inquiry: what exactly does the skeptic mean by his principle that “extraordinary claims require extraordinary evidence”?

What Makes a Claim extraordinary?

The problem is, the term extraordinary in this case is arbitrary. It is unreasonable for the skeptic to merely state that belief in the supernatural is extraordinary without further qualification. As always in rational discourse, defining terms is paramount.

Perhaps by extraordinary the skeptic means uncommon or rare. That seems reasonable. But the paradox is that rare things happen all the time. Identical twins are born, lotteries are won, atheists become Catholics, and new species of animals are discovered. But not even the most committed skeptic would deny the reality of these rare events—at least once the evidence is out.

The skeptic sees the lottery winner on the news, and he believes without demanding access to the winner’s bank statement. The atheist sees his twins on the ultrasound monitor, but he believes despite not seeing his babies directly with his own eyes. He believes without direct observation because of what he deems to be trustworthy evidence.

Perhaps we might say that because the evidence supports the truth of an unexpected reality, the evidence is extraordinary by virtue of what it proves.

Or maybe the skeptic means that belief in the invisible is extraordinary and therefore requires extraordinary evidence. Yet he does not suspend belief in the existence of Darwin, electrons, the mind of his best friend, or human free will, despite the fact that they are directly unobservable. He believes in these things on intuition and on the testimony of others, and for him that kind of evidence is good enough to warrant faith in the invisible.

Or perhaps he means by extraordinary what the term typically means—namely, something not ordinary. Ordinary is synonymous with usual or normal, so extraordinary would be “not the usual.” But here’s the thing: the majority position in regard to God’s existence—or the most usual belief across humanity—in almost every (if not every) era, including our own, has been belief in God, not atheism (this is the first premise of the common consent argument).

If this is the case, then perhaps we should flip this thing around and demand “extraordinary evidence” from the skeptics, since it is they who make the extraordinary claim, or the minority claim among men in this age and probably all the ages preceding it.

But there is still another question to ask :

What Constitutes Extraordinary Evidence?

Now, here’s another scenario. Perhaps the skeptic calls a supernatural claim extraordinary because he believes, unlike atheism, there is no good evidence for theism. On this view it is implied that the ordinary claim is that which has good evidence to support it.

But this viewpoint hinges on whether or not supernaturalism is, in fact, lacking evidentially and whether there is better evidence for atheism. If there is better evidence for theism than for atheism, then it is actually theism which is the more ordinary claim.

The skeptic must therefore demonstrate the evidential basis for his scepticism, and he must do it primarily with philosophy; for God is not just another “being among beings” taking up space in the empirical realm of the universe; rather, God is the sheer act of “to be” itself.

For while remaining present to the physical world as Creator and Sustainer, God is transcendent of the physical world, unbound by time, space, and matter. Thus trying to prove or disprove God’s existence by scientific evidence alone is as absurd as trying to prove or disprove Napoleon’s historical existence by geometry alone.

Thus the unbeliever is not exempt from a burden of proof, for even he is making a knowledge claim about reality: that God does not in fact exist. We wouldn’t let someone off the hook for asserting that they know aliens don’t exist. Rather, we would demand qualifying evidence for such a conclusive statement instead of accepting it as self evident.

So I would agree that if indeed there is no good evidence for a given belief, then to claim the contrary is to make an extraordinary claim. If an unorthodox claim is asserted—that unicorns exist, for example—there would be a burden of proof to show good evidence (or what philosophers call a defeater) for the commonly held belief that unicorns don’t actually exist.

Of course, in the case of unicorns there is no good evidence for their existence, and there is good evidence for its mythological fabrication. But unlike the arguments for unicornism—if there are any—the arguments for theism are a force to be reckoned with (as Trent Horn demonstrates in Answering Atheism and Hard Sayings) as they draw widely and deeply from philosophy, history, and science.

Thus the take-home point can be boiled down to this: the assertion “extraordinary claims require extraordinary evidence” requires further qualifications in order to function as an acceptable principle of reason. Merely asserting it is not enough to validate it.

Furthermore, what is needed to reasonably believe any claim seems to be just good evidence; or evidence that makes a claim more reasonable to believe than its opposite.

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