There’s been some confusion, conflict, and consternation on the atheist Internet lately. I offer this post as a resolution, if only people would relax for a minute and listen. We are all on the same side here, and we actually agree about the key ideas. The disagreement is what the logician Irving Copi referred to as “merely verbal,” as opposed to being a genuine disagreement over facts or values. It is ultimately (in my diagnosis) a disagreement about what is the best way of talking to ensure we win the debates and don’t get caught in useless side issues. That is, my point is about strategy, not the facts.

There’s a saying, “Claims aren’t evidence,” that has been repeated, but in a way that’s unhelpful to our cause. The idea behind it is that mere claims or mere assertions—ones that have no evidence or reasoning behind them—cannot be used as if they were support for some hypothesis. Sometimes the idea is just that merely claiming something does not prove that it is true.

If I claim something like, “My house elf will be freed from his servitude if I give him some clothing,” you would be right to laugh because my claim is silly. Merely making this claim does not prove that there is such a creature as a house elf, or that the gift of clothing would free it from bondage if it did exist. You would want a lot more proof, besides my say-so, to accept this claim.

Atheists complain about theists making mere claims all the time—about the veracity of the Bible, about the historicity of the Jesus story, about the supposed characteristics of a supreme being. So when an atheist says, “Claims aren’t evidence,” of course I know what they mean. The problem is that when we speak this way we make it possible for others to challenge us on irrelevancies, and then the point of the initial discussion gets lost in the weeds of arguing over words.

When other atheists tried to explain that this way of talking is problematic, somehow the conversation turned heated. From such a simple example, one where the disputants actually agree on the substance, it is easy to see how doctrinal schisms start!

The same thing also happened with the saying, “I don’t believe in evolution, I understand it.” This is meant to be a pithy response to the theist canard, “But don’t you ‘believe’ in evolution?” meant as if belief=mere faith. The theist here is committing a misuse of language; there’s no good reason for us to persist in that misuse in our reply. That makes it too easy for our opponents to get wrapped up in disputing about a word instead of us winning the argument on the issues. Besides, we want to say true things. (The technical term for the fallacy being committed by the theist is equivocation: They are using “I believe in God” to mean having mere faith, whereas the evolutionist is using “I believe evolution is true” to be mean accept based on good evidence.)

In both cases, claims and beliefs, the allies’ complaint is not that the sentiment is wrong. I can appreciate a pithy comeback, too, one that answers in kind when a theist says something stupid like, “I don’t have enough faith to be an atheist,” or asks as a rhetorical move, “Do you believe in evolution?”

The point is that people who understand evolution do believe that evolution is true. Saying otherwise is false and unhelpful when one of our objections against our opponents’ views is that they are imprecise in their use of language.

To expand on what I Tweeted to @InfiniDale3476, the saying, “I don’t believe in evolution, I understand it,” is misusing the word “believe.” The word “believe” has several senses, but its main meaning is, “Accepts as true/probable.” We can have degrees of belief: We can feel certain, highly confident, skeptical, unsure, disbelieving, etc. And beliefs can have degrees of evidence, too: The evidence for a scientific theory might show it is possible, probable, highly probable, improbable, impossible, etc. As Hume says, the wise person tries to align their degree of belief in a claim with degree of evidence for that claim.

The idea that there are degrees of belief is used all the time in evidence evaluation. Hence the legal standard of “beyond a reasonable doubt.” It implies the existence of unreasonable doubt, that is, a (negative) degree of belief that would be unreasonable given the available evidence, and unreasonable certainty (when the evidence doesn’t prove the thing definitively).

There is a secondary meaning of “Belief” which means something like “belief on faith alone,” as when someone says, “I don’t have proof that god exists, but I have Belief.” Theists talk as if this kind of Belief (against or without evidence) is a good thing, but it clearly isn’t. That said, we don’t need to let this secondary meaning of “belief” dominate the standard meaning when we use the word.

One should, of course, automatically dismiss mere belief, or belief on faith alone with no evidence. But that doesn’t mean all belief is unwarranted. Many of our beliefs do have excellent evidence, and therefore we have excellent reasons to believe those things.

The basic definition of knowledge, which Plato came up with to distinguish knowledge from what he called “mere opinion,” is that knowledge is justified true belief. You cannot know something you don’t believe. Yet having a belief itself is not the same as having knowledge. Likewise, we cannot know something that is false. (We might believe it strongly, but that’s not the same thing.) And a mere guess is not knowledge even if the belief happens to be true. (Plato called these “accidentally true opinions.” The difference between knowledge, false belief, and unwarranted belief (mere opinion), on this account, is that when you know some claim, you believe that claim, it is in fact true, and you have adequate reasons to believe it to be true.

Because you understand the theory of evolution and its evidence, you know the theory to be highly probably correct. (The evidence makes it extremely probable that evolution is the correct explanation of a vast array of biological phenomena.) The theory is so probable that it would be unreasonable to doubt it.

That is very different than religious belief in Young Earth Creationism, or whatever, since that belief not only has no adequate justification but has actually been falsified by the evidence. In a way, “believing” YEC is even worse than having a mere belief (belief against vs. without evidence).

But they are all still kinds of belief—beliefs of different quality.

And as I said in response to Twitter’s @SpeedWatkins,

Clarity is good for discourse. The problem isn’t with “claims” but with their evidential status. We can critique some claims as “mere assertions,” “bald claims” or “just speculation.” That is typically what’s at issue when people claim (!) claims aren’t evidence. Let’s be precise.

Besides, the claim, “Claims are not evidence,” is not evidence that the sentence, “Claims are not evidence,” is true. 😉