Jackson, Frank - Mind, Method and Conditionals: Selected Essays

The circumstances in which it is natural to assert the ordinary indicative conditional ‘If P then Q’ are those in which it is natural to assert ‘Either not P, or P and Q’, and conversely. For instance, the circumstances in which it is natural to assert ‘If it rains, the match will be cancelled’ are precisely those in which it is natural to assert ‘Either it won’t rain, or it will and the match will be cancelled’.