a.The relation between the two events is such that the speaker believes that the occurrence of one event, the 'caused event', has been realized at t2, which is after t1, the time of the 'causing event'. b.The relation between the causing and the caused events is such that the speaker believes that the occurrence of the caused event is wholly dependent on the occurrence of the causing event; the dependency of the two events must be to the extent that it allows the speaker to entertain a counter-factual inference that the caused event would not have taken place at that particular time if the causing event had not taken place at that particular time if the causing event had not taken place, provided that all else had remained the same.