Kant’s Rescue of our Knowledge of Nature from the Problem of Unknowable Essences

Anna Frammartino Wilks

Acadia University


The extent to which Kant’s revolutionary account of our knowledge of nature rejects the essentialism endorsed by some of his predecessors, such as Leibniz, Wolff and Baumgarten, is disputed among Kant scholars. Moreover some view Kant’s alleged rejection of essences as a denial of the reality of things in themselves, holding things in themselves to be identical with, or reducible to, essences (Hanna, 2006). Others deny both the reducibility of things in themselves to essences, and their non-reality (Ameriks, 2011). I argue that Kant did not deny the reality of either essences or things in themselves, but only their knowability. However, the unknowability of neither poses a threat to the possibility of our knowledge of nature. I defend this view with a broader than usual treatment of Kant’s metaphysical commitments, which considers the influence on Kant by Crusius, Euler, and Lambert and their work in natural philosophy. My treatment also goes beyond the standard texts – Kant’s Critique of Pure Reason and Prolegomena. I focus, in particular, on Kant’s Lectures on Metaphysics (Kant, 1762-1795), which provide a more comprehensive picture of Kant’s views on the ontological status of essences and things in themselves in our knowledge of nature.

In the metaphysics lectures Kant distinguishes between logical essence and real essence or nature. Logical essence is the “first logical inner ground” of the determinations pertaining to the “possibility of a thing,” which constitutes knowledge of its common predicates. Real essence is the “first inner real ground” of the determinations pertaining to the “actuality of a thing,” which constitutes knowledge of its particular predicates.

Equipped with these distinctions, Kant offers a straightforward answer to the question “Can we know the essence of things?”. He maintains that, while we may certainly know the logical essence of a thing, we cannot know its real essence or nature. The reason is that the former can be derived merely from concepts but the latter only from experience. However, because experience cannot provide knowledge of the complete set of predicates of a thing, we may only achieve an approximate and partial knowledge of the real essence, never complete knowledge of it.

While it would seem that this account entails the impossibility of acquiring any genuine knowledge of nature this is not of course what Kant concludes – as evidenced in his discussion of the various senses of “nature” in the metaphysics lectures and elsewhere. On a certain conception of “nature,” Kant ultimately claims that we could not have cognition of things at all unless we cognized them through their actions, which are governed by “the dynamic principles of nature” (Watkins, 2001). These principles can be known by our understanding because our understanding prescribes them to nature. Thus, according to Kant, neither the unknowability of things in themselves nor of real essences poses a problem for the knowability of nature.