Counterfactual semantics with an ontology of powers and actual objects

This dissertation is devoted to the exposition of an account of the truth--conditions counterfactual conditionals given in terms of mechanisms composed of objects and powers. The view is simply that a counterfactual conditional is true just in case there actually exist (or existed) a collection of objects that together form a mechanism that was poised to produce the consequent of the conditional under the condition that the antecedent obtain. Whether a congeries of objects forms such a mechanism depends on what powers the objects together possess. Thus the ultimate analysan's components are actual objects and their powers.;The first chapter comprises a review of the most popular approaches to counterfactual semantics. I take as representatives of three main approaches Nelson Goodman, David Lewis, and Frank Jackson. Each approach has a distinctive sort of counterexample which plagues it. I go over these and illustrate how a re-orientation of the sort I suggest promises to handle each case.;The second chapter presents the view in more detail and deals with special topics and objections. I address questions about the goals of the account and how to extend it to less central cases.;The third through fifth chapters all deal with issues in the logic of counterfactuals. They are not about formal logic per se, but rather about the ability of the account to explain the distinctive logical features of counterfactual conditionals. Each of the chapters addresses a distinct logical feature: the third with transitivity, the fourth with contraposition, and the fifth with conditional excluded middle. Throughout I use David Lewis's discussion of these issues in Counterfactuals as a dialectical foil. My contention is that the kind of explanations that Lewis gives are either empty, wrong, or non-existent. On the other hand, my approach promises convincing and illuminating accounts of the various features of the counterfactual conditional.