A Theory of Conditionals in the Context of Branching Time

Abstract

In Stalnaker [9] and in Stalnaker and Thomason [10], a theory of conditionals is presented that involves a “selection function”. Intuitively, the value of the function at a world is the world as it would be if a certain formula (the antecedent of a conditional) were true.

This began as a paper by Thomason, written in February 1977, revised and expanded in January 1978, and presented, with comments by Gupta, at the University of Western Ontario in May 1978. The present joint version was completed in October 1978. The basic ideas took initial shape in a series of discussions between Thomason and Walter Edelberg, who deserves a great deal of credit for his insights into the topic. In particular, he was the first to see the importance of the crucial inference we call ‘the Edelberg inference’. Later parts of the paper owe much to interactions with Robert Stalnaker, Bas van Fraassen, and each other.