Although such pairs of descriptions may in many cases be equivalent, in other cases, or in other ways, they might not be synonymous. Professor Alfred Freddoso writes:
Some prominent philosophers of science, dissatisfied with basically empiricist conceptions of natural law and scientific explanation, now argue that natural substances are best thought of as nonfree agents endowed with causal powers and that laws of nature are properly expressed by specifications of those powers rather than by generalizations (whether necessary or not) about events. The medieval Aristotelians, despite the inadequacy of their scientific theories, elaborated just such a philosophical conception of nature. Their writings in this area may prove to be illuminating, as has been clear ever since Peter Geach published his penetrating essay on Aquinas in Three Philosophers.
Comparing events to objects, some philosophers have noted that objects can change location, while events cannot. Following Hume, we would think of a magnet as the conjunction of numerous attraction events which occur at different times and places. Following the medievals, we think of a magnet has having the power of attraction, which naturally remains with it when it moves. The medieval view is more intuitive; the burden lies on Hume to show why we would need to override such an intuitive view.
