A SIMPLE THEORY OF CONDITIONALS 233 replies to this objection. Knowledge, pragmatics, and semantics can modulate these meanings. This chapter was the first exposition and defense of an axiom system and model theory for a conditional logic in the possible worlds framework, a theory designed to model counterfactual propositions. conditionals advanced inGillies(2009) andStarr(to appear) and transforms it into a uniform theory of conditionals that explains the basic contrasts be- tween the two varieties by paralleling the extension/revision contrast. 9pZV)1, 2 where the former holds factually, and the latter Introduction Trivially true conditionals can evolve inferentially, under Modus Ponens, from any premisses rFeal and r(1.q .Z. A uniform theory of conditionals is one which compositionally captures the behavior of both indicative and subjunctive conditionals without positing ambiguities. One is that the constructive empiricist make do with what his theory says is observable; but this will not provide a full demarcation. Modulation can add information about temporal and other relations between antecedent and consequent. A THEORY OF SUBJUNCTIVE CONDITIONALS 1. The authors outline a theory of conditionals of the form If A then C and If A then possibly C. The 2 sorts of conditional have separate core meanings that refer … A Uniform Theory of Conditionals 3 the philosophy of science on inference and inquiry.4 Why seek such alignment? This paper raises new problems for the closest thing to a uniform analysis in the literature (Stalnaker, Philosophia, 5, 269–286 (1975)) and develops a new theory which solves them. Another is that the constructive Leibniz, Boole, Frege and others established the idea of language as an epis-temic tool, and conditionals inhabit a The authors outline a theory of conditionals of the form If A then C and If A then possibly C. The 2 sorts of conditional have separate core meanings that refer to sets of possibilities. It is argued, using a version of the Ramsey test, that the truth-conditions for conditionals that are provided can explain why we assess counterfactuals in the way we do.