This article offers an anti-naturalist philosophical critique of the naturalist tendencies within qualitative concept formation as developed most prominently by Giovanni Sartori and David Collier. We begin by articulating the philosophical distinction between naturalism and anti-naturalism. Whereas naturalism assumes that the study of human life is not essentially different from the study of natural phenomena, anti-naturalism highlights the meaningful and contingent nature of social life, the situatedness of the scholar, and so the dialogical nature of social science. These two contrasting philosophical approaches inspire, in turn, different strategies of concept formation. Naturalism encourages concept formation that involves reification, essentialism, and an instrumentalist view of language. Anti-naturalism, conversely, challenges reified concepts for eliding the place of meanings, essentialist concepts for eliding the place of contingency, and linguistic instrumentalism for eliding the situatedness of the scholar and the dialogical nature of social science. Based on this philosophical framework, we subject qualitative concept formation to a philosophical critique. We show how the conceptual strategies developed by Sartori and Collier embody a reification, essentialism, and instrumentalist view of language associated with naturalism. Although Collier's work on concept formation is much more flexible and nuanced than Sartori's, it too remains attached to a discredited naturalism.