The Problem of Evidence


How can you look at this picture of the Andromeda Galaxy and not agree that the universe was created by my invisible friend? He shoots laser beams from his eyes and inexplicably cares about the well-being of earthworms! Isn’t he great?

Extraordinary claims require extraordinary evidence. Specific claims require specific evidence. But what exactly does that mean?

Suppose you have no knowledge of modern technology, and you come across a device with a touchscreen. Your mind, which so far has only known a natural and mechanical world, is dazzled by this new electronic technology. And of course, you have no idea how it works. What is your first assumption? That the device contains a spirit which reacts to your touch and changes the display? That it was made by an advanced alien race from another galaxy? That it’s a special revelation from a god and contains all knowledge you will ever need about how to live your life?

Whenever we come across something we can’t explain, we try to explain it, regardless of how much (or how little) evidence we have. Sometimes we’re pretty accurate, and sometimes we are wildly wrong. Over the past several centuries, old superstitions and supernatural explanations have given away to the solid rationality of science. Mental illnesses are no longer demon possession, but a malfunction of the physical brain. The sun is no longer carried across the sky by a god, but appears to rise and set due to the spinning of the earth. After all the discredited supernatural explanations, you’d think we would be more careful about making such assertions without solid evidence. Yet they continue.

Evidence is a problem for religion, and there are a few ways religious people tend to deal with it. If they lack evidence for their claims, it’s because you have to “have faith”…and supposedly once you’ve set aside reason and believed blindly, you’ll get the evidence you want. It’s never anything testable…you might feel better, or succeed at something you formerly failed, or your friend with a 50% chance of dying from cancer might “miraculously” be healed…just like 50% of everyone in his position.

How is this evidence? In order for something to be evidence for any given claim, it must point decisively toward that claim. The fact of my socks disappearing one at a time does not point decisively toward the existence of small sock-eating trolls who live in my dryer. Yet this is exactly the sort of reasoning employed so often by religious people.

Your god is not proven by ordinary yet uncommon events. If we look back at my Search for Truth, we will remember that in order to know something for sure, we must know that every possible alternative explanation is false. I may argue that the trolls in my dryer are real, but until I produce an actual live sock-eating troll, my claim is no more reasonable than claiming socks have a limited lifespan and will spontaneously disintegrate into a cloud of lint while in the dryer. Given the massive quantities of lint I pull off my dryer screen, you could say that there is more evidence to support this alternative, and thus it’s more likely to be true than the troll argument.

In this analogy, the fundamentalist steadfastly believes in the trolls, because they feel in their heart that it’s the correct answer. Someone else believes in the disintegration of socks, because it’s more in line with what we know of the world–how many people complain of trolls in their dryer, anyway?

What does the scientist do? Gather more evidence, of course. By engineering a controlled experiment, in which I am placed in a sealed environment with piles of socks, a washer, and a dryer, they can observe what happens and account for the whereabouts of every sock at the end. And the shocking results? My missing socks are behind and under the appliances, where I dropped them while transferring the load from the washer to the dryer.

The fundamentalist’s evidence is all in their head; they don’t need any further convincing that dryer trolls are real because they already believe it. Perhaps they read on a website that “Dryer trolls must exist because our socks keep disappearing one at a time!” The person who believes the disintegration theory has some external evidence, but they don’t bother to actually verify whether or not it points to the conclusion. The scientific approach is designed to produce evidence that points in only one direction, or at least rules out enough possibilities that one stands out as the most likely. For example, if I pull out my washer and find my missing socks, I’ve ruled out both the sock-eating trolls and the disintegration theory.

What it comes down to is the elimination of possibilities–in the beginning, the only evidence I have is that my socks are disappearing. This evidence is consistent with trolls, with spontaneous disintegration, and with any number of other explanations. It is useless evidence. And yet this is exactly the sort of evidence given for religions all the time. From an objective point of view, I need a logical reason to choose one religion over all others. It would be irresponsible if I simply believe one is true because it makes me feel good, or because a large number of other people believe it, or because I’ve seen some things I can’t explain.

The problem we all face is that objectively, most religions have no more evidence, and are no more logical, than any other. Pascal’s Wager is useless because there are many religions that warn of hell, and if you belong to any one of them, most of the others have you on the naughty list. How do you choose, when you’re literally damned no matter what you do? Maybe it isn’t a choice that needs to be made, if there is no decisive evidence for any of them.

By simple rational thinking I can take a supposed piece of evidence from one religion and apply it to any other. The world around us calls for a creator, and thus “God” must be real? If that piece of evidence really did point definitively to a god, which god would it point to? There are many to choose from.

There must be a divine source of morality? What if I believe that our morality was genetically coded into us by an alien programmer who lived in his mom’s basement in the Andromeda galaxy? How is that any more or less reasonable than claiming our morality came from the Christian god? Even if the existence of our morality demands an intelligent source outside of humanity, that is not evidence for any particular source.

We want everything to be black and white, simple and understandable. But if you really want to base your beliefs on reality, you need to make sure your evidence doesn’t easily point to several dozen different possibilities. If you can’t narrow it down, then perhaps you’ll need to be satisfied with the fact that sometimes we just don’t know. You’ll have to make yourself comfortable in the gray and keep yourself open to various possibilities, so if someday new information comes along which would make your evidence point in a decisive direction, you aren’t so enamored with one particular possibility that you reject reality in favor of fantasy.


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