The Concept of Physical Law

The medieval concept of a law of Nature (physical law) as literally being a law of God mandated to Nature has been superseded in the modern period by two nontheistic concepts: the Regularity theory, which would make physical laws nothing more than those true universal statements that happen to describe Nature, and the Necessitarian theory, which maintains that there is a "necessity" in Nature and that events "accord with" physical laws. These latter two theories have competed since the eighteenth century when David Hume first called attention to their differences. In the early twentieth century, the Regularity theory dominated, but in recent decades there has been a marked revival of the Necessitarian theory.

The Concept of Physical Law is an original and creative defense of the Regularity theory. The defense is in three parts. First, Professor Swartz argues that the standard objection to the Regularity theory – that it makes too many fictional events "physically impossible" – turns on a mistaken view of what Regularists mean by "physical impossibility." Secondly, he challenges the Necessitarian epistemology by arguing that it is impossible to construct an empirical test that could distinguish between those events Necessitarians call "mere accidents" and those they call "nomologically necessary." Finally, the Regularity theory is defended on the grounds that it avoids one of the most stubborn problems in philosophy: free will and determinism. The Necessitarian theory cannot account for human beings' free wills. For on the Necessitarian account, whatever happens, including our choosing to act in one way rather than another, is "determined" by antecedent (or prevailing) conditions and physical laws, neither of which are of our choosing. In the Regularity theory, the problem of free will cannot even arise, for what happens is not "determined" by physical laws. The relationship is quite the reverse: What happens in the world is what "determines" physical laws. Professor Swartz stresses that human beings can choose (some of) the world's physical laws. We do this simply by choosing to do what we do.

Other topics in this important work include: the distinction between instrumental scientific laws and true physical laws; the distinction between failure and doom; potentialities; miracles and marvels; predictability and uniformity; statistical and numerical laws; and necessity-in-praxis.

This abstract was prepared by Cambridge University Press to advertise the first (1985) edition of The Concept of Physical Law.