  It is just these peculiarities that create philosophical challenges not met with in physics and chemistry. Kant tackles them in the latter half of his third magnum opus, the Critique of the Power of Judgment (1790). In particular, he claims that attempting to explain organisms creates an inevitable conflict within reflective judgment, the faculty we employ in empirical concept formation, taxonomic classification, and the explanatory unification of particular laws. Kant describes that conflict in the Antinomy of Teleological Judgment (CJ §§ 69–78; 5: 385–415). The Antinomy obtains between two regulative principles, herein prefixed by an ‘R’ to distinguish them from two similar constitutive principles that Kant briefly discusses in the same place: