Abstract:Humean reductionism about laws of nature appears to leave a central aspect of scientific practice unmotivated: If the world's fundamental structure is exhausted by the actual distribution of non-modal properties and the laws of nature are merely efficient summaries of this distribution, then why does science posit laws that cover a wide range of non-actual circumstances? In this paper, we develop a new version of the Humean best systems account of laws based on the idea that laws need to organize information in a way that maximizes their cognitive usefulness for creature like us. We argue that this account motivates scientific practice because the laws' applicability to non-actual circumstances falls right out of their cognitive usefulness.

Humean reductionism about laws of nature is the view that the laws reduce to the total distribution of non-modal or categorical properties in spacetime. A worry about Humean reductionism is that it cannot motivate the characteristic modal resilience of laws under counterfactual suppositions and that it thus generates wrong verdicts about certain nested counterfactuals. In this paper, we defend Humean reductionism by motivating an account of the modal resilience of Humean laws that gets nested counterfactuals right.

In this paper, we argue that the popular claim that laws of nature explain their instances (explanatory laws) creates a philosophical puzzle when it is combined with the widely held requirement that explanations need to be underpinned by ‘wordly’ relations (explanatory realism). We argue that a “direct solution” to the puzzle that accounts for both explanatory laws and explanatory realism requires endorsing at least a radical metaphysics. Then, we examine the ramifications of a “skeptical solution”, i.e., dissolving it by giving up at least one of these two claims, and argue that adopting it is more favorable to Humean reductionists than to anti-reductionists about laws of nature.

The Humean best systems account (BSA) identifies laws of nature with the regularities in a system of truths that, as a whole, best conforms to scientific standards for theory-choice. A principled problem for the BSA is that it returns the wrong verdicts about laws in cases where multiple systems, containing different regularities, satisfy these standards equally well. This problem affects every version of the BSA because it arises regardless of which standards for theory-choice Humeans adopt. In this paper, we propose a Humean response to the problem. We invoke pragmatic aspects of Humean laws to show that the BSA, despite violating some of our intuitive judgements, can capture everything that is relevant for scientific practice.

Humean Supervenience (HS) is a metaphysical model of the world according to which all truths hold in virtue of nothing but the total spatiotemporal distribution of perfectly natural, intrinsic properties. David Lewis and others have worked out many aspects of HS in great detail. A larger motivational question, however, remains unanswered: As Lewis admits, there is strong evidence from fundamental physics that HS is false. What then is the purpose of defending HS? In this paper, we argue that the philosophical merit of HS is largely independent of whether it correctly represents the world’s fundamental structure. In particular, we show that insofar as HS is an apt model of the world’s higher-level structure, it thereby provides a powerful argument for reductive physicalism and explains otherwise opaque inferential relations. Recent criticism of HS on the grounds that it misrepresents fundamental physical reality is, therefore, beside the point.