chapter  1
24 Pages

On assertion and indicative conditionals

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' . Similarly, the circumstances in which it is natural to assert 'Not both P and Q' are precisely those in which it is natural to assert 'Either not P or not Q' . We explain the latter coin­ cidence of assertion conditions by a coincidence of truth condi­ tions. Why not do the same in the case of the conditional? Why not, that is, hold that 'If P then Q' has the same truth conditions as 'Either not P, or P and Q'?