Laws of nature characteristically manifest themselves or issue in regularities. It is natural, therefore, in Ockhamist spirit, to consider whether laws are anything more than these manifestations.

When philosophers hear the phrase ‘Regularity theory’ they are inclined almost automatically to think of a Regularity theory of causation. It is important, therefore, to be clear at the outset that what is being considered here is a Regularity theory of laws.

The Regularity theory of causation appears to be a conjunction of two propositions: (1) that causal connection is a species of law-like connection; (2) that laws are nothing but regularities in the behaviour of things. It is possible to deny the truth of (1), as Singularist theories of causation do, and then go on either to assert or to deny the truth of (2). Alternatively, (1) can be upheld, and either (2) asserted (yielding the Regularity theory of causation), or (2) denied. The reduction of cause to law, and the reduction of law to regularity, are two independent doctrines. They can be accepted or rejected independently.

It therefore appears that the Regularity theory of causation entails the Regularity theory of laws of nature, because the latter theory is a proper part of the former. By the same token, the Regularity theory of laws of nature fails to entail the Regularity theory of causation. Our concern is with the Regularity theory of law.