In a recent article in the journal Theology and Science, David Glass and Mark McCartney explore the claim that science can explain away God. The article entitled ‘Explaining and Explaining Away in Science and Religion’ (available for download here or from the publisher’s website here) explores the concept of explaining away using probability theory, identifies key questions to determine whether explaining away occurs in a given case, and then applies this approach to three case studies: evolution and design; fine-tuning; evolutionary accounts of religious belief. The work was carried out as part of a project on ‘Explaining and Explaining Away’ based at Ulster University and funded by the John Templeton Foundation.
The claim that science explains away God is a very common one, particularly in the writings of the new atheists. For example, Richard Dawkins states that
Historically, religion aspired to explain our own existence and the nature of the universe in which we find ourselves. In this role it is now completely superseded by science.
The general idea is that while belief in God made sense before modern science, as science explains more and more about how the world works, there is less and less need for God. To put it another way, scientific explanations have made theistic explanations unnecessary. For example, if science explains why the planets orbit the sun, there is no longer any need to appeal to God as an explanation: there is no need for two explanations when one will do. Now sometimes this kind of reasoning works and sometimes it doesn’t.
For example, if my alarm clock doesn’t go off, a possible explanation is that it is faulty, but once I realise that I forgot to set it, there’s no longer any reason to think it’s faulty. (Of course, this doesn’t mean it definitely isn’t faulty; there’s just no reason to think that it is.) There’s no need for two explanations when one will do. The second explanation (I forgot to set the alarm) explains away the need for the first explanation (the alarm clock is faulty).
But consider another case. A road traffic accident occurs and a possible explanation is that it was caused by drink-driving. But further evidence comes to light showing that it was caused by the car going through a red light. Does this second explanation (car through red light) remove the need for the first explanation (drink-driving)? No, because not only are the two compatible, but it is quite possible that drink-driving was the cause of the car going through the red light. No explaining away occurs in this case.
The question is: how do we decide whether explaining away occurs in a given case? That’s where this work fits in. Based on probability theory, it identifies various questions that can help determine whether explaining away occurs. The upshot of this is that it is much more difficult to explain away God than some atheists seem to think. There is no easy way to move from ‘science explains’ to ‘science explains away God’. In each of the three case studies, it is argued that there is no good reason to think that explaining away occurs. In particular, there is no good reason to think that evolution explains away design even in biology.
 Richard Dawkins, The God Delusion (London: Bantam Press, 2006), 347, emphasis in original.