Aristotelian Realism in Peirce’s Harvard Lectures

Abstract: If an act can always be made consistent with other acts by defining a rule that covers all of the observed cases, how can one know which rule one follows when one acts? This paper approaches this question through an analysis of one strand of thinking in Charles Sanders Peirce’s 1903 Harvard Lectures and in some entries that Peirce contributed to the Century Dictionary . Peirce argues for a strong form of “scholastic realism,” which insists on the “reality of thirdness” of universals such as natural laws. The Harvard Lectures identify thirdness with Aristotelian “entelechy”—actuality or realization—and thus as a principle that is irreducible to any combination of power and act. When a being is in this state of realization, it signifies the universal. This paper argues that if natural things realize natural laws and persons realize reasons, then acts can be rationally determined by a single rule that one is following.