Review of 'Just Six Numbers: the deep forces that shape the universe' by Martin Rees
If you want to read more about cosmic fine-tuning, one of the best short books is 'Just Six Numbers: the deep forces that shape the universe,' by Martin Rees.
Rees discusses the six numbers of the title that contribute to a life-supporting universe: the ratio of the strength of electrical forces to the force of gravity; the strength with which atomic nuclei bind together; the density of the universe; the cosmological repulsion constant; the amount of unevenness in the big bang; and the number of spatial dimensions. He argues that if any of these numbers were much different from what they actually are, life would be impossible.
Rees comes to a different conclusion from 'God: new evidence' - he believes in the multiverse. (See 'God or the Multiverse') However, it would be a mistake to say that he argues for a multiverse rather than a creator. He only mentions the possibility of a creator twice:
These six numbers constitute a 'recipe' for a universe. Moreover, the outcome is sensitive to their values: if any one of them were to be 'untuned', there would be no stars and no life. Is this tuning just a brute fact, a coincidence? Or is it the providence of a benign Creator? I take the view that it is neither. An infinity of other universes may well exist where the numbers are different. Most would be stillborn or sterile. We could only have emerged (and therefore we naturally now find ourselves) in a universe with the 'right' combination. (p. 4)
'Others adduce the 'tuning' of the numbers as evidence for a benificent Creator, who formed the universe with the specific intention of producing us (or, less anthropocentrically, of permitting intricate complexities to unfold). This is the tradition of William Paley and other advocates of the so-called 'argument from design' for God's existence. Variants of it are now espoused by eminent scientist-theologians such as John Polkinghorne; he writes that the universe is 'not just "any old world," but it's special and finely tuned for life because it is the creation of a Creator who wills that it should be so.'' (p. 166)
Rees immediately goes on to say
'If one doesn't accept the 'providence' argument, there is another perspective...'
So he simply does not engage with the possibility that the fine-tuning points towards a Creator. However, Rees is an excellent communicator, and as a short account of the physics and cosmology involved, this book is hard to beat.
Martin Rees is the Astronomer Royal, Master of Trinity College, Cambridge, and Baron Rees of Ludlow.