chapter xiii on, the topic is consistency.[41] Consistency, though it

refers primarily to plot, must also include characterization. In general, characterization must be consistent with the morality of the individual purpose, with the moral habit of the social group, with the received idea of the person, and finally with itself.[42] In particular,

it is necessary in the characters, as in the plan of the actions, to seek always the inevitable or the probable, so that the saying or doing of such-and-such things by such-and-such a person, just as the happening of this event after that, shall be inevitable or probable. Evidently, therefore, the solutions also [as well as the complications] of plots must come about from the plot itself, and not, as in the Medea ... by the _deus ex machina_.[43]

In a word, consistency of characterization is part of the causal weaving of the plot.