ANALYSIS 66.4 OCTOBER 2006 Analysis 66.4, October 2006, pp. 269–75. © Cory Juhl Blackwell Publishing Ltd.Oxford, UK and Malden, USAANALAnalysis0003-26382006 Blackwell Publishing Ltd.October 200666426975ArticlesCory Juhl FINE-TUNING IS NOT SURPRISING Fine-tuning is not surprising Cory Juhl A number of recent works by physicists and others have noted what appears to be a very surprising coincidence. If the constants of physics had been slightly different, life as we know it would not have existed. This has astonished the writers of those works, and several explana- tions have been suggested. A popular explanation for fine-tuning among non-physicists has been that a Divine Intelligence has seen to it that the constants were set to just the right values for life as we know it to emerge. 1 The most popular explanation for fine-tuning among physicists seems to be that our universe is one among an enormous number, where the values of the constants vary across these universes (e.g. Singh 2005: 487–88). This ‘many-universes’ explanation is supposed to make fine- tuning unsurprising via an argument along something like the following lines. Since universes of practically all relevant types, both tuned and untuned, exist, it is unsurprising that some universe of our finely-tuned type exists. Further, since only such universes contain living things, it is unsurprising that we living things observe that our own universe is fine- tuned for life. What I am calling the ‘standard fine-tuning argument’ is an argument that fine-tuning, i.e. the values of the constants in our actual physical laws on the one hand, and the values compatible with life as we know it on the other, and the precise ‘match’ between them, jointly yield a surprising coincidence. I will argue against that view, and for the view that fine- tuning is an expected consequence of unsurprising features of the actual physical world and of life as we know it. I conclude that the fact that there is some fine-tuning for the existence of life as we know it is fairly unsurprising, given what we know. One relevant feature of our world is that it consists of some smallish number (less than 100, say) of basic components, and that the behaviour of these components is governed by (alternatively, accurately modelled by) some smallish number of coupled partial differential equations. Let’s label this feature of our universe moderate complexity. There is a sense 1 Some authors think that the fine-tuning phenomenon ‘[t]oday … is widely regarded as offering by far the most persuasive current argument for the existence of God’ (Collins 2000).