In this chapter we have constantly referred to the _Poetic_ of Aristotle, and it will be well at this point to summarize his view of the nature, parts, and aim of tragedy. Before doing so, however, we must be clear upon two points: the standpoint of his criticism and the value of his evidence. It was long the habit to take this work as a kind of Bible of poetical criticism, to accept with blind devotion any statements made therein, or even alleged[119] to be made therein, as constituting rules for all playwrights for ever. Now, as to the former point, the nature of his criticism, it is simply to explain how good tragedies were as a fact written. He takes the work of contemporary and earlier playwrights, and in the light of this, together with his own strong common sense, æsthetic sensibility, and private temperament, tells how he himself (for example) would write a tragedy. On the one hand, could he have read _Macbeth_ then, he would have condemned it; on the other, could he read it now as a modern man, he would approve it. As to the second point, the value of his evidence, we must distinguish carefully between the facts which he reports and his comment thereon. The latter we should study with the respect due to his vast merits; but he is not infallible. When, for instance, he writes that “even a woman may be good, and also a slave; though the woman may be said to be an inferior being, and the slave quite worthless,”[120] and blames Euripides because “Iphigenia the suppliant in no way resembles her later self,”[121] we shall regard him less as helping us than as dating himself. But as to the objective facts which he records he must be looked on as for us infallible.[122] He lived in or close to the periods of which he writes; he commanded a vast array of documents now lost to us; he was strongly desirous of ascertaining the facts; his temperament and method were keenly scientific, his industry prodigious. We may, and should, discuss his opinions; his facts we cannot dispute. The reader will be able to appreciate for himself the statement which follows.