Metaphysics of natural species (3)

To the first (epistemological) question: is it possible to have knowledge of ENs without knowing their essence? Duns Scotus' answer is yes. It should be noted in passing that the impossibility of knowing the essence is indeed linked, as G. Pini insists, to an intrinsic cognitive limitation, but this is not the only reason for the impossibility of knowing the essence. Pini, to an intrinsic cognitive limitation, but this is not a product of our nature: it is purely contingent, linked to the Fall, and therefore to an accident of history. On the contrary - and this further reinforces the idea that, at the level of our nature, there is something that gives solidity to our knowledge - Duns Scotus considers that we have a kind of ability to name things, a " habitus vocalis ", a natural propensity or disposition to know what EN's terms name, what they designate (a theme not unconnected with his "propositional realism"), which we'll see at work, in other forms, in Leibniz as well as in Kripke and Putnam.

For the second (semantic) question: what do the terms of EN designate? Duns Scotus rejects the consequence we might be tempted to draw from the fact that we have no knowledge (other than by description) of essence: against Thomas Aquinas and Henry of Ghent, he maintains that our terms do indeed refer to things as they are, and not to names (or to what will become, with Locke, purely nominal definitions), or to things as they are understood(res ut intellectae). We don't have to go through the concept (Thomas). Here again, closer to an externalist position than an internalist one, Duns Scotus shows that: 1. we do not know things de re; we know them only on the level of description, de dicto. 2. But this does not prevent us from saying that when we speak of things, it is indeed of real things that we speak, and not as they are understood. 3. And that doesn't stop us from referring to them.

We've identified a few lessons to be learned from Scotian analysis. If we want to give substance to a metaphysical knowledge of ENs, we should: 1. carefully distinguish between the epistemological, semantic and metaphysical orders. We are not bound to see a perfect correspondence between them; 2. to defend a "thin" form of essentialist realism, which certainly requires support from an aliquid, but without postulating direct access to a quiddity. 3. Just because we have to go through descriptions to know things as they are, doesn't mean we can't find a basis in nature for them. So classifications are not purely nominal. Even if groupings in nature are made only by the way we refer to them, they do correspond (and our terms do refer) to something of and in nature (semantic realism). It's a position that's already almost a step ahead of Locke's own.

The last part of the lesson was therefore devoted to introducing the classic confrontation between Locke and Leibniz on the question of ENs in the modern era. Starting with Locke, we first emphasized the change of perspective, the crucial questioning of Aristotelian essentialism, against a backdrop of (empiricist) criticism of (Cartesian) rationalism and a priori knowledge of substances by a rational faculty. For Locke, we observe manifest similarities between discrete particulars, and it is through these abstract ideas or "nominal" essences, by a semantic decision, that we formulate the notion of EN which we then use for our classifications. Wax, no doubt, has underlying characteristics that could in principle explain its malleability, fusibility and so on. But these characteristics are unknowable (in practice) and therefore play no part in our classifications. Hume would follow and amplify Locke: we cannot penetrate to the heart of the essence of things, to a rational a priori vision of the causal structure of the world, on pain of sinking into sophism and illusions. We concluded with two remarks: what Locke's and Hume's critique is aiming at is the idea of a possible a priori epistemic access to the nature of reality: in short, it's because our epistemology would be bad (the idea that an a priori rational faculty could grasp the essence of natural species) that our metaphysics would be bad too. In which case, could we envisage two other hypotheses: 1) that essentialism could be defended on non-Aristotelian grounds, and 2) the idea of a posteriori rather than a priori knowledge of essences (which is precisely what authors like Kripke and Putnam will do)?