There are many theories of causation, some of which are more at home with the project of natural theology than others. One theory that blocks the cosmological and design arguments for theism is the view that causation is reducible to laws of nature. On this view, to say that one thing causes another is just to say that when one event (say the ignition of gunpowder) is subsumed under a law of nature, another event (namely, an explosion) follows necessarily. But if causation is reduced in this way, it will not be possible to argue for a causal explanation of the laws of nature because that explanation will presuppose the very laws it is seeking to explain. Thus, the appeal to God is blocked.
One variation of this theory states that all human knowledge of causation is of a law-like sort. The only cause-and-effect relationships we can know about happen between events which we regularly observe to co-occur. Thus, we can know that gunpowder ignitions cause explosions only if we have observed these ignitions to be followed by explosions on a regular basis. But again, this poses a problem for natural theology and its warrant for claiming that God created the universe. Why? Because we haven’t observed God’s creative acts being regularly followed by the inception of new universes! Also, God’s singular act of creation (ex nihilo) bears little resemblance to the causes that human beings are able to detect by observing regular, law-like patterns between events. Thus, even if God actually did cause the universe, that fact would be beyond our ability to know about. So again, natural theology is in trouble.
But what should we make of the claim that causation can be reduced to natural laws, to regularities, or indeed to anything at all? What is meant by “reduction” in this context? Different definitions have been proposed by various philosophers, so I will propose my own definition in my next post. See you then!
 David Hume (1779) makes a similar complaint against natural theology when he writes: “When two species of objects have always been observed to be conjoined together, I can infer by custom the existence of one whenever I see the existence of the other, and this I call an argument from experience. But how this argument can have a place where the objects as in the present case [i.e. when God is supposed to cause the universe], are single, individual, without parallel or specific resemblance, may be difficult to explain.” See his Dialogues Concerning Natural Religion, (ed.) H.D. Aiken, Hafner, 1948, p. 23.