Can the desire for efficiently systematised theories in science be explained from within a powers metaphysics? It is plausible that the traditional ‘Powers Theory of Laws’, endorsed by many friends of powers, does not alone provide such an explanation. This has led a number of recent authors to argue that a ‘Powers Best System Account’ of laws would be a preferable alternative. This account borrows a method for determining laws from the Humean and applies it to a reality of powers. (...) Here I claim, to the contrary, that this account is both internally unworkable and, anyway, completely undermotivated when compared with the traditional view. Apart from some brief suggestions for alternative accounts, I’ll conclude that the powers theorist still has their work cut out to explain systematising in science. (shrink)

Lewis’s original Best Systems Account of laws was not motivated much by pragmatics. But recent commentary on his general approach to laws has taken a ‘pragmatic turn’. This was initiated by Hall’s defence against the charge of ‘ratbag idealism’ which maintained that best systems accounts should be admired rather than criticised for the inherent pragmatism behind their choice of desiderata for what counts as ‘best’. Emboldened by Hall’s pragmatic turn, recent commentators have proposed the addition of pragmatically motivated desiderata to (...) complement or replace the canonical desiderata of strength and simplicity. This, they hope, will allow their revisionary BSAs to respond better to various counterexamples against the original account. While the pragmatic turn itself is well taken, here I problematise these revisionary approaches. First, there are reasonable responses to the counterexamples from within the canonical BSA. Second, while actual laws may satisfy the newly proposed desiderata, there are reasons to think these desiderata cannot be constitutive of laws. By comparison, the canonical desiderata appear to be relevant to explaining why and when the revisionary desiderata will reflect pragmatic features of the laws and better reflect the motives behind practitioners of fundamental physics. (shrink)

In this paper, we put forward an alternative interpretation of time-reversal symmetry in philosophy of physics: Humean time-reversal symmetry. According to it, time-reversal symmetry is understood as a heuristic, epistemic virtue of the best system, not as a property of the Humean mosaic. One of the consequences of this view is that one of the main arguments against a primitive direction of time is rendered harmless, which paves the way for primitivism about the direction of time.

I describe three extant attempts to identify the global external symmetries within a Humean framework with theorems of some or other deductive systematization of the world, respectively, the best system, a meta-best system and a maximally simple system. Each has merits, but also serious flaws. Instead, I propose a view of global external symmetries as consequences of the structure of Humean-consistent world-making relations.

The laws of nature have an internal explanatory structure. This leads to interesting questions for metaphysicians of laws. What is the nature of this explanation? Marc Lange has recently argued in favor of metalaws: higher-order laws governing other laws, of which symmetry principles may be an example. Lange argues that his view, unlike its competitors, can make sense of the explanatory power of symmetries. I agree with Lange about the explanatory structure of laws but disagree with him about the nature (...) of this explanation. I then present a Humean view that neatly captures the explanatory power of symmetry principles. (shrink)