We must notice what it is that Thuc

We must notice what it is that Thucydides is explaining. Aitia and prophasis are both subjective words used to explain an actor's reason for acting, not objective words used to explain why something happens (the most objective word for >>cause is aition). Formally, Thucydides' grievances are grievances on both sides (23.vi, cf. 66, where the affair of Potidaea is interpreted in such a way as to provide each side with a ground of complaint against the other), but they are in fact presented so as to show how the Peloponnesians came to make war on Athens, and the truest reason contrasted with the particular grievances is the Peloponnesians' truest reason for making war on Athens. This should cause no surprise, partly because it is strictly true that the Peloponnesians began the war, and partly because Thucydides was himself a patriotic Athenian.