Metaphysics of natural species

The lecture followed on from last year's reflection on the contours of a possible metaphysical knowledge of nature. The aim was to examine this in greater depth, testing the proposed model by applying it to certain characteristics that suggest that reality can be or already is (?) cut up into natural "species" or "kinds" of things. "Water", "gold", "cat", "car" seem to correspond to more natural articulations of things than "being bigger than a car" or "alcoholic beverage". But is this really so? And what do these classifications correspond to? Are they already there in nature, or are they simply the result of our actions?