Logic and Science v. the Fine Tuning Fairy Tale

You know the fine tuning argument right? Life on earth is possible only because an infinitely improbable set of parameters has converged to make life possible. Since the likelihood of this happening spontaneously is infinitely small, then a designer, a.k.a. god, must have intervened to set as appropriate all the values that made life arise. This is the favorite argument proposed by believers in intelligent design, a.k.a creationism 1.0.1, to refute the concept of abiogenesis and, more broadly, of evolution itself.

Joe Thornton, a biologist at the University of Oregon, has written three beautiful paragraphs (in a larger, technical response to Michael Behe's hijacking of his research group's paper on molecular evolution, published in Nature magazine) that are intended to rebuff Behe's contention that some mechanisms in nature are so complex that they could not possibly have arisen spontaneously. The same argument can be made not only against Behe's argument of irreducible complexity (hence design), but against the fine tuning argument as well, as clearly and as cogently as ever.

Here is what Thornton wrote:

Finally, Behe erroneously equates “evolving non-deterministically” with “impossible to evolve.” He supposes that if each of a set of specific evolutionary outcomes has a low probability, then none will evolve. This is like saying that, because the probability was vanishingly small that the 1996 Yankees would finish 92-70 with 871 runs scored and 787 allowed and then win the World Series in six games over Atlanta, the fact that all this occurred means it must have been willed by God.

Consider the future: there are countless possible that could emerge from our present state, making the probability of the one that actually does evolve extraordinarily low. Does this mean that the future state that will ultimately emerge is impossible? Obviously not. To say that our present biology did not evolve deterministically means simply that other states could have evolved instead; it does not imply that it did not evolve.

Consider your own life history as an analogy. We can all look back at the road we have traveled and identify chance events that had profound effects on how our lives turned out. “If the movie I wanted to see that night when I was 25 hadn’t been sold out, I never would have gone to that party at my friend’s house, where I met my future spouse….” Everyone can tell a story like this. The probability of the life we actually lead is extraordinarily small. That obviously doesn’t mean that its historical unfolding was impossible.

Case closed. Again.

(Thornton's response can be found here And here is the post that sparked my curiosity about Thornton's research.)