Nominalism and the Rise of Empirical Natural Philosophy

Ockham's denial of extramental universals carried direct consequences for how nature could be studied. If genuine reality consists only of singular substances and qualities, then scientific knowledge cannot rest on grasping some really existing common essence shared by many things; it must instead be built up from repeated intuitive cognition of particular cases, generalized cautiously through experience and demonstration rather than through metaphysical insight into a shared "nature." This shift reoriented natural philosophy away from the Aristotelian search for the hidden formal and final causes that supposedly explained why kinds of things behave as they do, and toward a more descriptive, quantitative, and parsimonious account of how things in fact behave, since positing occult causal powers not required to save the observed phenomena violated the same razor Ockham applied to universals. Ockham himself argued, for instance, that local motion is not a distinct thing (res) added to a moving body over and above the body successively occupying different places, eliminating "motion" as a separately existing entity in favor of the simpler claim that a body is merely in different places at different times.