By a semantic difference, I mean here a difference in the assertive content that utterances

One standard way of approaching the problem of analyzing conditional sentences begins with the assumption that a sentence of this kind expresses a proposition that is a function of the propositions expressed by its component parts (plus, perhaps, some features of the context in which the sentence is uttered). The task is to characterize this function. But there is also a long tradition according to which conditional sentences–at least some conditional sentences–are used to perform a special kind of speech act. A conditional assertion is not a standard kind of speech act (assertion) with a distinctive kind of content (a conditional proposition) , but rather a distinctive kind of speech act that involves just the two propositions, the ones expressed by the antecedent and the consequent. There has been considerable controversy about which of these two strategies for explaining conditionals is better.