Abstract

Laws of nature concern the natural properties of things. Newton’s law of gravity states that the gravitational force between objects is proportional to the product of their masses and inversely proportional to the square of their distance; Coulomb’s law states a similar functional dependency between charged particles. Each of these properties confers a power to act as specified by the function of the laws. Consequently, properties of the same quantity confer resembling powers. Any theory that takes powers seriously must account for their resemblance. This is the challenge set by the paper. The first part is devoted to Armstrong’s view according to which property resemblance reduces to partial identities between categorical properties. I argue that Armstrong’s solution to the challenge involves accepting determinable properties but that these should not be admitted. In the second part, I argue that dispositional essentialism can satisfactorily account for orderings among powers in terms of degrees of overlapping potentialities.