Conditionals

by

Christopher Gauker

Introduction

In English, a conditional is a sentence of the form, “If p, then q” (or of a synonymous form). The part of the sentence following “if” is the antecedent, while the part following “then” is the consequent. An indicative conditional is a conditional having an antecedent in indicative mood, such as “If Fred is here, then he can help you.” A subjunctive conditional is a conditional having an antecedent in the subjunctive mood, such as “If I were in Paris, then I would be happy.” (In English, the present-tense subjunctive mood, as it occurs in the antecedent of a conditional, is usually indistinguishable from the past tense, and the past-tense subjunctive is indistinguishable from the past perfect.) What are called counterfactual conditionals are usually just subjunctive conditionals, though some authors draw a distinction. An important touchstone in discussions of conditionals is the so-called material conditional, which, by stipulation, is true if and only if either the antecedent is false or the consequent is true. The philosophical problem of conditionals is, in part, the problem of explaining the conditions under which a conditional sentence is true, or true relative to pertinent parameters. It is also the problem of characterizing the class of logically valid arguments containing conditionals. For instance, we would like to know whether the argument “I will meet you tomorrow; therefore, if I die tonight, then I will meet you tomorrow” is logically valid. The philosophical problem of conditionals has proven to be difficult and controversial, and for that reason the problem of conditionals has been used as a primary motivation for several different approaches to semantic theory.

General Overviews

All three of the texts below summarize several aspects of the state of play in the discussion of conditionals. But while Edgington 1995 and Bennett 2003 aim to defend particular theories, Nute and Cross 2003 attempt to remain neutral.

• Bennett, Jonathan. A Philosophical Guide to Conditionals. New York: Oxford University Press 2003.

  DOI: 10.1093/0199258872.001.0001E-mail Citation »

  Bennett advocates the probabilistic approach of Adams in his treatment of indicative conditionals, but advocates the Stalnaker-Lewis approach for subjunctive conditionals. In the course of his argument, Bennett touches on many of the major issues concerning conditionals, and for that reason his book can serve as general introduction.

• Edgington, Dorothy. “On Conditionals.” Mind 104 (1995): 235–329.

  DOI: 10.1093/mind/104.414.235E-mail Citation »

  This is a survey of the subject of conditionals aimed at defending Adams’s probabilistic theory.

• Nute, Donald, and Charles B. Cross. “Conditional Logic.” In The Handbook of Philosophical Logic. Vol. 4. 2d ed. Edited by Dov Gabbay and Franz Guenthner, 1–98. Dordrecht, The Netherlands: Kluwer Academic, 2003.

  E-mail Citation »

  This is a technically precise survey and comparison of semantic theories of conditionals. It focuses on variations of the possible-worlds approach and on the belief-revision approach.