June 21, 2007
On The Nature of Proof
Creationists (how we love them) might suggest that we can’t “prove” that evolution is true, not 100% anyway. About Atheism just posted a nice succinct response (written by a forum member) to that argument, which I wanted to share.
Creationist: You can’t prove evolution is true, 100%.
Me: But evolution has been proved true beyond a reasonable doubt. It’s like in court, to prove a defendant is guilty, the jury needs to decide that it is beyond a reasonable doubt that the claim is true.
Creationist: A ha! But innocent people are sent to jail all the time!
Me: Okay, but imagine a different court. In this one, a juror has to first pass years of tests to prove that he knows about the law and the case at hand. Then, he and a million others who also passed the test hear case after case after case. A million different defenses [sic.] are launched against the truth of the claim. Every single of the million jurors after every single of the million cases concluded that there was no reasonable doubt that the claim was true. A single juror, in one case, could say “Not true” and the defendant would go free. But that never happened, and still never happens to this day. Because this defendant gets a million trials every day. And still, not one “Not true” has been found.
That’s the case that evolution is true.
Creationist: Yeah but someday we’ll find a Not true, but for you it’ll probably be too late. Enjoy hell loser.
Me: :-\1
It comes down to a fundamental misunderstanding of the role of science. I just recently finished my final undergraduate essay ever, On The Nature of Proof for my “History and Philosophy of Mathematics” subject. One section of the essay deals with this issue specifically2
The scientific notion of proof is not dissimilar from that in general use. While scientists (or, perhaps, the media which portrays scientific research to the public) may occasionally be casual in their use of the word “proof”, when questioned about the certainty of their results (and thus, whether their work actually constitutes “proof”), they might reply: “Scientists don’t talk about ‘proof’, period. We leave that to the mathematicians… Change the word ‘proof’ to ‘evidence’, and it makes more sense.”3
Scientists seem to have little problem admitting that they do not, in fact, prove anything. Karl Popper, whose ideas defined the modern scientific method, suggested that “scientific experimentation [is not] carried out with a view to verifying or finally establishing the truth of theories; … we can never finally prove our scientific theories, we can merely (provisionally) confirm or (conclusively) refute them”4
It should be clear that any use of the word “proof” in science is either accidental, or a deliberate attempt to promote “pseudo-science” or non-science as legitimate. Scientific theories may be contingently true, but it is not the goal of science to provide “proof”. While science may have higher standards of evidence than the general population, scientists (like the general population) seek “evidence that is sufficient to establish knowledge of a conclusion”5, not certain truth.
- About Atheism: Proving Evolution is True [↩]
- Rosalion, Richard (2007) On The Nature of Proof [↩]
- Myers, P.Z. (2005, June 16) “Volokh’s question“ [↩]
- Thornton, Stephen, “Karl Popper“, The Stanford Encyclopedia of Philosophy (Winter 2006 Edition), Edward N. Zalta (ed.) [↩]
- Chappell, R. (June 17, 2005) “Evidence, Knowledge, and Proof“. [↩]
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