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Can A Regularity Theory of Laws Provide an Effective Account of Causation?

The search for causes is natural to the human mind, which believes that nothing happens without reason. In the words of philosopher and metaphysicist Alyssa Ney (2014), an effective account of causation is incredibly important since it could amount to “a complete account of the nature of our universe and what it is like” (p.220). So, for example, it can inform us of the relation of a bullet fired (the cause, ‘c’) and John F. Kennedy’s assassination (the effect, ‘e’). Whilst theories of causation explore this in considerable detail, theories of laws can potentially enhance such theories to account for causation. A regularity theory of laws (hereafter ‘RVL’, since it is a regularity view of laws) seemingly develops nomic regularity theory, for instance, the regularity theory which aims to account for causation via the laws of nature (hence 'nomic'). RVL apparently develops the nomic-based theory by (i) maintaining that the laws of nature describe c and e since laws regularly result in e following from c, thus accounting for the relation between cause and effect to account for causation, and (ii) explaining what the laws of nature—which are meant to explain causation—consist of themselves. Or so the story goes.

This article will explore point (ii) to assess whether RVL really provides a plausible account of causation by developing the nomic regularity theory based on the laws of nature. Though the regularity view of laws certainly helps to understand causation, it does not provide a particularly satisfying account of causation.

Figure 1. Scottish Philosopher David Hume, famous for his radical empiricism and account of causation (Jessop, 2022).

Regularity Theories of Causation

Though RVL may improve general understanding of causality, something keeps going wrong when causation is accounted for via regularity whilst avoiding logical necessity. One must start from the beginning.

First, there is the so-called ‘simple’ regularity theory (‘SRT’), originally introduced by David Hume in 1740. Causes are regularly followed by the same kind of effect according to SRT, thus accounting for causation. Consider Stathis Psillos’ (2014) formalisation of SRT, whereby c causes e iff (if and only if):

  1. c is spatiotemporally contiguous to e;

  2. e succeeds c in time; and

  3. All events of type C (i.e., events that are like c) are regularly followed by—or are constantly conjoined with—events of type E (i.e., events like e).

Causation on SRT is ‘explained’ by the fact that things like c are regularly followed by things like e. At first glance, this makes a plausible enough case for saying that c causes e.

Figure 2. A Treatise of Human Nature: Hume here introduces regularity to explain causation (Hume, 2022).