This peculiar argument maintains that the regularities of nature - the "laws of nature" as revealed by their approximations, the "laws of physics" - can only be due to the action of a divine mind, and thus point to God. This argument is made, for example, in Another Flew's There is a God. There are actually two varieties of the argument, founded on two conceptions of matter.
In the simplest viewpoint, matter (physical substance) is perceived to be a dynamic, self-propagating entity. A certain configuration of matter in the present causes the emergence of another configuration in the future through the laws of causation. The question is then why are there laws of causation at all, why doesn't matter propagate in a completely chaotic manner. It is argued that Naturalism does not provide a reason for this, while God does.
The second viewpoint is more radical, viewing matter as dead and inert and so unable to propagate itself. Matter cannot create matter, cannot cause anything. This is because matter exists, but laws of nature cannot force it to do some thing and not the other as they are not matter and therefore do not exist under radical naturalism; something that doesn't exist cannot explain anything. The continuum of time can thus only be explained by something immaterial creating matter, supporting matter, at each point in time - and doing so, so we find, in just the way that conforms to physical laws. This is essentially the view that physical laws require an immaterial thing to exist (namely, the laws themselves as some sort of Platonic entities with causal powers), so you might as well assume God does as well.
Naturalism eschews both viewpoints. It assumes neither that matter is inert nor that it is active, instead insisting simply that Nature can be described by universal, uniform descriptions - with no unique entities such as God, or entities with magical powers such as Souls, whose existence will make the proper description of reality non-uniform. By the very insistence on universal descriptions, true at any place and time, one by necessity obtains that if Nature obeys any universal mathematically precise laws whatsoever then it will have certain regularities. The revealed laws must therefore be regular (either random or deterministic, but always regular), under naturalism. Far from being unexplained under naturalism, laws of nature are a necessary consequence of it.
References and Notes
- Specifically, the requirement of laws universal in place and time results in the conservation of momentum and energy correspondingly. Other requirements, such as desiring that rotating one's viewpoint won't lead to different physical laws, result in other symmetries and conservation laws (the conservation of angular momentum in this case). Thus the laws of nature arise out of the search for the most objective description of reality, the one that is most symmetric - applying to any observer, regardless of where he is, when he is testing the law, in what orientation he is in, and so on. That said, current research hints that it isn't strictly possible for things to be the same in every place and time since place and time are only approximate descriptions of reality, but the principle of a universal description remains valid. One should also note that symmetries lead to conservation laws only under the principle of least action, or a similar assumption; this principle may require further explanation, but is not at odds with the Naturalistic viewpoint.
- See Nick Covington's review of There is a God for this point, based on the work of Victor Stenger and Brian Green. Covington also nicely demolishes Flew's other main arguments (the Fine Tuning Argument, the Cosmological Argument, and an Argument from Abiogenesis).