Abstract
The first lesson recalled what a metaphysical knowledge of nature requires: we must, in a first therapeutic phase, bypass our illusions about modalities and realism; then set out the axes of the conceptual method of analysis, the role ofa priori and intuition, certainly, but also the proper use of the sciences to achieve a scientific metaphysics that is not scientistic; say what the metaphysician's commitments are : how he can defend realism without subscribing to "metaphysical realism", and why his realist commitment implies scientific realism. The main points of the dispositional realist metaphysics thus established were then recalled: 1) a form of dispositional scholastic realism (DSR) assuming that there are real universals, but not that all universals are real: the real is that which "signifies" something real; 2) a semantic realism that forces us to clarify the concept of causality, to determine the meaning of our dispositional attributions, to understand why the reduction of dispositional attributions to conditionals is inoperative, and why reduction statements cannot express "everything" that dispositional predicates signify; 3) an RSD in search of real properties and not just predicates, based on a "causal criterion of existence" (XE) ; 4) a scientific RSD that admits, as an abductive hypothesis called for by the explanatory necessity of science, certain real universals; 5) an essentialist RSD that is not substantialist but relational or structural, forcing a redefinition of essence (conceived, no longer as a static quiddity, a pure natural species, a simple bundle of habits, but as a disposition-habitude) and of causality itself (not just efficient but final or intentional) and of laws: dispositions find their intelligibility in the conditional necessity of laws, but laws are a true description of the world only insofar as they are grounded in what things can do (in the sense of real possibilia metaphysically necessary though discovered a posteriori).
