Sumários
Possible worlds (4)
14 Março 2024, 14:00 • Ricardo Santos
Possible worlds and quantification: constant domain or variable domains? Undesirable consequences of the constant domain. Plantinga’s two problems regarding variable domains. The debate between necessitism (the view that [necessarily] everything necessarily exists) and contingentism (the view that [possibly] something possibly does not exist). Williamson’s argument for necessitism. Key role of the third premise, Objectual Dependency (saying that a singular proposition ontologically depends on the object it is about). Comparison with Plantinga’s argument from contingentism to the denial of objectual dependency. Can we have both contingentism and objectual dependency?
Possible worlds (3)
7 Março 2024, 14:00 • Ricardo Santos
Plantinga’s actualism, a moderate form of modal realism. Two main claims: (i) everything is actual; (ii) possible worlds are abstract objects. To simplify things, one can equate states of affairs with propositions. Possible worlds are consistent and maximal sets of propositions. Accounting for contingent existence by postulating variable domains. Different truth conditions of “Possibly there are Fs” and “Some things are possibly F”. Two problems: (1) Are there things that don’t exist? (2) Could there be facts (true propositions) about things that don’t exist? Plantinga’s solution in terms of individual essences (haecceities).
Possible worlds (2)
29 Fevereiro 2024, 14:00 • Ricardo Santos
Modal ambiguities: syntactic and semantic. De dicto and de re modalities. Actualism and possibilism. Lewis’s modal realism (cont.). Spatio-temporal individuation of worlds. No overlap between worlds and no causal relations. Counterparts. Promise of a reductive analysis of modality. Objections: irrelevance and ontological extravagance.
Possible worlds (1)
22 Fevereiro 2024, 14:00 • Ricardo Santos
The widely spread use of possible worlds in contemporary philosophy: in logic (truth-conditions for the modal operators), epistemology (epistemic possibilities), philosophy of language (propositions), metaphysics (properties and essences), philosophy of mind (supervenience of the mental). Kinds of necessity and possibility. Introduction to Lewis’s extreme modal realism: possible worlds as parallel concrete universes (or spacetimes). Lewis’s indexical view of actuality.
Material Constitution
15 Fevereiro 2024, 14:00 • Ricardo Santos
Puzzles of material constitution. Hylomorphism and the constitution view. Four-dimensionalism and the doctrine of temporal parts. Nihilism. Mereological essentialism. The dominant kinds view. Relative identity.
Three basic metaphysical notions: truth, existence and identity. Fundamental principles regarding them: (i) the disquotational principle of truth, (ii) the claim that everything exists and (iii) Leibniz’s law. Apparent counter-examples. Kripke’s argument for the necessity of identity.