The aim of this paper is to revisit the major arguments of the seventeenth century debate concerning laws and powers. Its primary points are two. First, though the dominant conception of nature was such that there was no room for power in bodies, the very idea that laws govern the behaviour of matter in motion brought with it the following issue, which came under sharp focus in the work of Leibniz: how possibly can passive matter, devoid of power, obey laws? (...) Though Leibniz’s answer was to re-introduce powers, two radically different conceptualisations of the relation between laws and powers became available after him. Hume denied powers altogether, whereas Newton thought that to introduce a power is to introduce a law. The second main point will be that though laws were meant to replace powers, the real dilemma ended up being not laws vs powers, but rather necessity vs non-necessity in nature. To exploit, an expression used by Newton, the question was: what is the place of necessity in the frame of nature? (shrink)

Dispositionalist accounts of scientific laws are currently at the forefront of discussions in the metaphysics of science. However, Mumford has presented such accounts with the following dilemma: if laws are to have a governing role, then they cannot be grounded in the relevant dispositions; if on the other hand, they are so grounded, then they cannot perform such a role. Mumford’s solution is drastic: to do away with laws as metaphysically substantive entities altogether. Dispositionalist accounts are also deficient in that (...) they either make no mention of the significant role of symmetries in science, or attempt to inappropriately eliminate this role. Here we shall attempt to motivate a structuralist view of laws by showing how it evades Mumford’s dilemma and accommodates the role of symmetry principles. In addition we shall consider how this view deals with a number of issues that dispositionalism finds problematic and indicate how the supposed necessity of laws and the explanation of relevant counterfactuals look from this structuralist perspective. (shrink)