These two words do not, as a rule,

These two words do not, as a rule, offer any special difficulty to students of Greek, except when they try to decide what precisely their meaning is when they are used by Thucydides and Polybius in discussing the causes of a war.' Only then, perhaps, do they realize the shortcomings of their Greek lexicon and begin to wonder whether the Greek use of these words is logical and clear. Attempts have been made to clear up the apparent difficulty in editions of Thucydides and elsewhere, and I shall not take time to consider the merits and shortcomings of earlier discussions,2 except to point out that they often fail to recognize the full range of meaning which the first of these two words displays in Greek writers; we must be prepared to admit that, if we try to confine ourselves to translations like "excuse" "motive" or "cause" we are doomed to permanent misunderstanding.