When he had said that those who are slaves are by nature intended to be slaves, he at one stroke excluded the fatal question whether those particular men who happened to be slaves were the particular men intended by nature to be slaves. For that question would have tainted each case of slavery with doubt. And since the fact of being a slave was not evidence that a man was destined to be one, no certain test would have remained. Aristotle, therefore, excluded entirely that destructive doubt.
