Benjamin Brast-McKie

This paper extends Kit Fine’s (2012a, 2012b, 2017a, 2017b, 2017c) truthmaker framework to provide a novel task semantics for tensed counterfactual conditionals. Instead of taking possible worlds to be primitive elements in a model, possible worlds will be defined in terms of states, parthood, tasks, and times where the task relation encodes the possible transitions between states. Rather than invoking primitive relations for similarity or imposition, possible worlds will be compared at a time independent of that time’s past and future where the comparison will be carried out in modal and mereological terms. After reviewing motivations for this approach, I will provide the hyperintensional semantics for counterfactuals that is implemented in the model-checker software along with a unified logic for counterfactual, modal, and tense operators. I will then extend the language to include further tense operators in order to analyze forwards, backwards, and backtracking counterfactuals.

This paper develops a theory of propositional identity which distinguishes necessarily equivalent propositions that differ in subject-matter. Rather than forming a Boolean lattice as in extensional and intensional semantic theories, the space of propositions forms a non-interlaced bilattice. After motivating a departure from tradition by way of a number of plausible principles for subject-matter, I will provide a Finean state semantics for a novel theory of propositions, presenting arguments against the convexity and nonvacuity constraints which Fine (2016, 2017a,b) introduces. I will then move to compare the resulting logic of propositional identity (PI) with Correia’s (2016) logic of generalised identity (GI), as well as the first degree fragment of Angell’s (1989) logic of analytic containment (AC). The paper concludes by extending PI to include axioms and rules for a subject-matter operator, providing a much broader theory of subject-matter than the principles with which I will begin.