René Descartes introduced the modern notion of a “law of nature.” The Medieval Scholastic notion of “natural law” was more of a teleological notion; and in particular with respect to human beings, “natural law” described not how we in fact behave but how we ought to behave—the “unnatural” was, in effect, the deviant. The Cartesian notion was more about how phenomena in the world of nature unfold in an orderly way. Contemporary science speaks of many such “laws” and philosophers since Descartes have proposed several interpretations of just what law-claims really claim.
Descartes was quite serious in transposing a juridical metaphor into science. For Descartes, “laws of nature” were facts about the regular behavior of the material world that God had ruled (legislated) into being. Unlike the Empiricist tradition beginning with Hume, Descartes did not believe that the world always operates as you would predict solely on the basis of physical laws. For Descartes, human free will was a separate influence of a non-material soul that could interact causally with matter. Descartes seldom addressed miracles, but he did believe that even the ordinary, lawful unfolding of the world requires divine concurrence and that God could have created a world with a totally different set of laws.
Some of Descartes’ Early Modern successors, notably Newton, were very keen on the idea of miracles. Others, like Leibniz, Hume, and Laplace, were not. Leibniz, a theist, believed that God made a perfect universe that would operate on its own, and that belief in miracles was tantamount to believing that God was a sloppy clockmaker who had to step in and reset the clock from time to time.We can see here that the modern notion of a “law of nature” involves the metaphorical transposition of a familiar source into a way of thinking about something else. Hume’s understanding of “laws” as exceptionless generalizations and “miracles” as violations of those generalizations made the notion of a miracle self-contradictory: an exception to an exceptionless rule.
We can see here that the modern notion of a “law of nature” involves the metaphorical transposition of a familiar source (juridical laws) into a way of thinking about something else (regularities found in nature). The idea of “breaking” a law has a clear enough meaning in the source domain—to break a normative law is to act in a fashion contrary to it, such as doing what it forbids. But there are further questions, such as whether—especially in an Early Modern context—laws apply to Sovereigns as well as to those they govern. Many historical arguments for miracles have operated within these terms: that God, as Sovereign and Author of the laws, is himself above and exempt from them, so his doing something inconsonant with a law is not really breaking a law, even if it is not in accord with it. (Laws are for the subjects, not the Sovereign.) I think such arguments make some sense at least at the metaphorical level. But it is not clear to me that the notion(s) of “laws of nature” that have emerged out of the application and transformation of the metaphor do, need, or should include a dependence on the original notion of, and strictures of, that of “breaking” a law. There are, indeed, questions to ask about how we should think about events that are not in accordance with the laws we find in the sciences. But I do not believe the normative juridical metaphorical source gives us a good standpoint for making sense of these. The metaphorical transposition of an idea or model from one domain to another is almost always partial—some parts of it capture the patterns of the new domain well enough (otherwise it is not an apt metaphor to begin with), others do not, and even with those that do, our understanding eventually pulls free from its metaphorical moorings if it is to take on a productive life of its own. It is with what develops out of this that we need concern ourselves.
Mechanics, Laws, and Interpretations
First, very briefly, I shall touch on the most relevant change within the sciences since Descartes and Newton: the change from “deterministic” laws of Classical Mechanics to “probabilistic” or “indeterministic” laws of Quantum Mechanics. These descriptions are potentially misleading or at least prejudicial. It would be better to say that the mathematical formulations of Quantum laws utilize probabilistic mathematics, while those of the Classical laws do not. For there are, above and beyond the mathematical laws, questions about how to interpret what they claim.For there are, above and beyond the mathematical laws, questions about how to interpret what they claim. Some interpretations of Quantum Mechanics indeed involve an indeterministic universe. Others do not. And some, like the many-world interpretations, are hard to place and very strange indeed.See this for more. Conversely, Newton (who proposed the basic laws of Classical Mechanics) was not a determinist and believed in miracles.
What I wish to address, instead, are two philosophical interpretations of laws in general—whether Classical or Quantum—which I shall call the empiricist and causal-powers interpretations. David Hume pioneered a classical empiricist view of laws: that they are true universal (exceptionless) claims about how objects in nature always actually behave. Hume’s own examples, like “all swans are white” or “fire causes burning” do not represent the actual scientific laws of even his own day, but we may take his characterization to include the view that, say, falling bodies and planetary orbits always happen exactly in accordance with Newton’s gravitation law. In the twentieth century, logical positivists and empiricists developed a more sophisticated version of this view using the resources of modern logic. Both forms of empiricism would seem to preclude miracles and free will: an event that falls under even one (true) law that makes universally true claims would be causally determined, and a single exception to a universal claim would either invalidate it as a law or be logically inconsistent. Believing in miracles would seem to threaten the very idea that there are (true) natural laws, and this seems a very high price to pay.
But there are a number of problems with this view, as philosophers of science began to realize in the 1970s. The most blatant of these is that such views treat each law, individually, as a true universal claim. But in fact bodies seldom behave as any one law describes. A falling body can also be affected by wind resistance and magnetism, for example. Newton had seen this, and suggested that we can factor the causal influences into different components (gravity, inertia, etc.) and then combine them through vector algebra, though this only works if the factors are truly independent. What Newton’s own system suggests about the gravitation law is not that it describes how bodies always actually behave, but that gravitation is a force which is one regular causal contributor to such behavior, describable in mathematical terms.
This is an example of the other contemporary approach, the causal theory of laws, on which laws describe causal powers or potentialities. These describe idealized patterns found at many levels—physical, chemical, biological, psychological, economic. Perhaps there is also true randomness in the universe; but if not, what happens is the result of the combination of all these causal factors. The big differences from Classical physics are that it is not clear that these are always truly independent, and that the laws themselves are idealized. (Sometimes, in incompatible ways, as in the case of Relativistic Gravitation and Quantum Mechanics.)
Yet in another respect, this framework is one Newton would have embraced. He recognized that the science of his day was incomplete, and essentially open-ended, and hence the “complete” list of causal influences was not fully specified. And I think this is also why it seemed quite natural to him to believe in his system of laws and also believe in miracles: nothing about our commitment to gravitational force, or any other force, or even all the forces regularly at work in the world, excludes the possibility of things like divine action. It would simply be one more causal factor.What you would get if these additional causal factors are added is something else, and involves powers that lie beyond the scope of the sciences. (As would human free will.) On this view, neither miracles nor free will would count as a violation of laws of nature, because each law of nature expresses only one regular contributor to the causal mix. What actually happens depends on all causal factors that are at work in a given situation. What the laws would produce without a miracle or human free will is one thing, and can be studied by the sciences. What you would get if these additional causal factors are added is something else, and involves powers that lie beyond the scope of the sciences, at least if the latter are understood as the study of regular causal regularities, addressable through controlled experiment, as free action, whether divine and human, is by definition not underwritten by laws.
This, of course, does not prove the reality of either miracles or free will, nor that they are entailed by the causal powers view. However, it is, in my view, a powerful compatibility proof—of the compatibility of laws and free will with what I regard as the best available interpretation of natural laws that has been forthcoming from philosophy of science. Belief in miracles and free will is perfectly compatible with belief in scientific laws, properly understood.