science, open minds and wild guesses

I've just returned from holidays, when I did a bit of reading on the "finely tuned universe" (see my blog, was it all planned?).

In brief, science has discovered a number of areas where the laws or facts of cosmology seem to be exactly right to allow the universe to develop as it has, and only miniscule variations would have prevented the universeas we know it from existing, and certainly prevented the development of life on earth. It seems to be highly improbable that this could have happened by chance.

Some scientists simply ask the question why, some argue that these facts demonstrate the God exists, others argue that the facts can be explained without God.

One argument suggests that it is both wrong in theory and impossible in practice to draw any conclusions about the probability of a universe being "well designed" - see for example this paper.

Despite this, well qualified scientists have had a go:

• Oxford mathematician and cosmologists Roger Penrose, who worked with Stephen Hawking in developing understanding of black holes, has estimated that the odds of all of these scientific facts being 'just right', as they are, are 1 in 10^10^123 - that's 10 raised to the power of 10 to the power of 123, a number so large it cannot be written out, so large that the odds are effectively zero. i.e. Penrose was saying that the universe could not possibly have happened by chance. (It is worth noting that Penrose is coy about the question of whether he believes in God, but it would appear that he is not part of any conventional religion.)

• On the other hand, Victor Stenger, Professor of Physics and Astronomy at the University of Hawaii, and an atheist, has examined the question via a computer simulation and concluded (in a paper) that if four of the most important variables are allowed to take up a large range (plus or minus 10 orders of magnitude), it is more than 50% likely that a viable universe (one that would last for at least a billion years) could form.

It would be an understatement to say that these two views are very different! We might explain some of the difference by the fact that Stenger's model and criteria are very limited - e.g. he only considers 4 out of perhaps 15 constants, his ranges are small compared to the possible ranges, and that surviving a billion years without any reference to what form the universe takes is not a very useful criterion. We might suspect that atheist Stenger doesn't approach the question with an open mind, whereas Penrose may. We may also conclude that Penrose has the better scientific credentials.

But having said all that, what do we make of such an impossibly vast difference in the conclusions of two well qualified scientists applying their science to this question. At the very least, it's a challenge to scientific objectivity on this subject.