The Review of Metaphysics

This wide-ranging collection of essays examines the metaphysical underpinnings and implications of competing accounts of laws of nature. The first six essays offer interpretations of key figures in the seventeenth and eighteenth centuries, with the remaining six essays providing contributions to current debates on the topic. This is not to suggest a sharp bifurcation between the exegetical and the philosophical, however, as most authors show an appreciation for the reciprocal illumination of contemporary philosophy and its history. To avoid a fragmented discussion, I will focus only on those essays of most interest to readers of this journal.

One way to understand early modern debates about laws of nature is in terms of a bottom-up as opposed to a top-down approach. On the former understanding, laws are grounded in things' natures and powers, whereas the latter sees them as being externally imposed by God. Using this framework, Walter Ott argues that Bacon and Spinoza both opt for a bottom-up approach that renounces an unalloyed mechanism. Laws just are the powers of things inscribed into their natures, and yet are still lawlike insofar as they express unchanging dispositions. One [End Page 803] consequence of this is that the world is governed by a multiplicity of natures and laws that can obstruct each other. Stathos Psillos also employs these interpretive categories in his discussion of Descartes, Malebranche, Berkeley, Leibniz, Hume, and Newton. For these thinkers, laws, like the powers they displace, impose either metaphysically or naturally necessary connections in nature, even if such necessities cannot be inferred from observed regularities. This necessity, however, is top-down and not bottom-up since it emanates from a law giver and not bodies' powers.

In their contributions, Helen Hattab and Mary Domski examine Descartes's relation to his predecessors and successors. Hattab identifies three features of Descartes's laws—they are universal, play a causal role in nature, and determine every outcome in nature—whose provenance she seeks to trace. Hattab shows that the first two features are presaged in the works of late fifteenth-century Aristotelians, but since these same thinkers posit bottom-up active powers that determine changes, the third is not. Sebastian Basso, contrariwise, is a more direct precursor to Descartes since one finds all three characteristics of laws in his oeuvre. Domski defends Descartes against the criticisms of Newtonians that his derivation of the laws of nature from God's immutable nature compromises divine freedom and overstates the capacity of human reason to comprehend the God's essence. On her reading, Descartes's laws are certain and necessary only from the vantage point of human reason. Similarly, Newton's laws are best understood as principles that, as applied to mathematical bodies, are indubitable and rationally certain. The differences between Descartes and Newton are therefore not as sharp as might initially appear.

Angela Breitenbach elucidates Kant's views on laws of nature in a way that simultaneously preserves their nomic necessity and knowability. Arguing against alternative accounts that achieve one at the expense of the other, Breitenbach maintains that our access to specific natural laws is through "empirical reflection." This means that empirical inquiry searches for laws that systematically unify nature and that take the necessary form imposed by a priori principles of reason.

Several of the later essays revolve around the Best System Account, which sees laws as true generalizations that supervene on nonnomic facts and are part of the system that achieves the best balance between strength and simplicity. Especially notable here is Michela Massimi's convincing argument in favor of a perspectivalist version of the BSA that recognizes that, rather than being fixed, standards of simplicity and strength differ throughout the history of science. Natural laws are nomically necessary just in case they figure in perspectives that vary across time and scientific communities. This account both remains grounded in the actual practice of scientific communities and yields laws resilient to theory change.

Of the entries not principally historically oriented, those by Stephen Mumford and by...