Thursday, January 13, 2011

Creationists Don't Understand Consilience

Of all the commenters at Uncommon Descent, "Kairosfocus/GEM of TKI" (actually Gordon Mullings) is the one with the second largest stupidity-verbosity product.

Here he is citing science "journalist" Richard Milton to argue against radiometric dating. Quoting Milton, he says radioactive dates cannot be falsified, that any scientist debating a date would be regarded as a crackpot, that errors are corrected to the currently accepted value, and only dates conforming to current understanding will get published.

Mullings and Milton don't understand how science works. With radiometric dating, the essential point is that we have multiple, independent analyses all leading to essentially the same estimates for, e.g., the age of the earth. (Read, for example, Dalrymple's book with that title.) It is the consilience of our estimates that give us confidence. The evidence is now so strong that a single discordant result will not cause scientists to throw away all previous results; rather, someone disputing the age of the earth will have to amass evidence that is roughly equal in strength (or stronger) to the case for our current estimate. Not only that, anyone calling the age of the earth into question is going to have to explain what, precisely, has gone wrong with all the evidence we have -- why, precisely, do all those dates obtained by independent investigators match up so well?

And that's the way it should be. Science is not mathematics, where a single counterexample can invalidate a theorem (but even there, not always! -- the message of Lakatos' Proofs and Refutations). In science, a very strong evidentiary case doesn't get overthrown by a few isolated results that suggest another conclusion. There are simply too many possibilities for error in scientific experiments for that.

Let's apply Milton's four objections to, for example, the distance from the earth to Alpha Centauri. Just like radiometric dating, we have no direct experience of this distance; any scientist claiming a substantially different distance from 4.37 light years would be regarded as a crackpot; an experiment giving a substantially different distance would be scrutinized carefully for sources of error; and it is unlikely (unless the evidence case were extremely strong) that another distance would get published.

In fact, we have an example of this from the history of Alpha Centauri itself: James Henderson studied the distance to Alpha Centauri using parallax in 1832-3, but he didn't publish his results because the great distance he obtained made him suspect an error. Only after Bessel determined the distance to 61 Cygni in 1838 did Henderson change his mind. Once again, the consilience of the two independent experiments increased our confidence in the results.

So the Mullins-Milton objections apply to all of science, not just evolution. Were we to accept them as definitive, all of science would disappear.


Tomato Addict said...

I went a few rounds with Kairosfocus a while back over Dawkins' Weasel algorithm. I found him to be willfully ignorant - incapable of acknowledging basic facts, or even to agree to a definition of "latching". His greatest strength seems to be having too much free time on his hands.

Anonymous said...

In case you don't know, Milton's geology cred is the result of him being in some sort of geology 'club', the only requirement of which is to pay the dues. I forget the specifics, but I engaged a creationist several years ago who hawked Milton's geology "credentials" as proof that what he claimed was correct....

The whole truth said...

Who's the one with the first largest stupidity-verbosity product?

Jeffrey Shallit said...