Originally Posted by Disinfo Agent

This post is motivated by several recent exchanges with evolution doubters in Lonest@r's Intellectual Design thread.

When confronting relativists* who come up with some version of the old chestnut that "science is just a belief system like any other", BAUTers have recently tended to reply that "natural science is not about proof, that's for mathematics". Although I've probably done it too a few times, I've been thinking lately that this might be counterproductive.

Originally Posted by Disinfo Agent

I understand what people mean by that, and I agree: there are no absolute certainties in science. But if you look up the word "proof" in a dictionary, you'll find that it has many meanings, not all of which imply absolute, logically necessary certainty. For example, the following is from the Merriam-Webster online. I've omitted the irrelevant definitions, but left two interesting though outdated ones.

1 a: the cogency of evidence that compels acceptance by the mind of a truth or a fact b: the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning

2 obsolete: experience

3: something that induces certainty or establishes validity

4 archaic: the quality or state of having been tested or tried; especially : unyielding hardness

5: evidence operating to determine the finding or judgment of a tribunal

One of the common notions of proof is as used in courts. This is probably the one people are most familiar with, in fact, and notice how it does not imply absolute certainty. In the US judicial system, all that is required is that a case be "proven beyond reasonable doubt". I would say the standard of proof is even more stringent in science than in courts, in general. So I see no problem at all with saying, for example that "there is proof of evolution", or that "evolution has been proven", so long as we do not try to imply that this means definitive proof.

I would like to suggest, then, that we not let relativists lure us into semantic discussions of what is proof. Rather than reacting with a defensive and rather academic caveat, let's go on the offensive, assuming by default that proof means accepted scientific evidence -- the only kind of proof that it makes sense to consider, as far as evolution is concerned.

Originally Posted by Disinfo Agent

Should our oponents wish to use a more stringent definition of proof, let them take the first step and define their own terms.

Originally Posted by Disinfo Agent

I am persuaded that the average person rarely ponders over these philosophical fine distinctions; they quite sensibly adjust their understanding of the word "proof" to the context. Since we are not speaking only to our relativist opponents, but (above all) to a broader audience, let's adjust our speech to the common sense of that audience, rather than to the minutiae of our opponents.

Originally Posted by Disinfo Agent

In short, the next time someone comes at you with "there is no proof of evolution", don't say "well, science is not about proof anyway", but instead reply "why yes, there is proof", and then list a few examples, such as the ones here.