So, for Aquinas and Aristotle, because the quality that most clearly sets off the category 'human' is "a reasoning animal" actions that interfere with that part of human identity are unnatural and interfere with telos.
Their flaw is in concluding that because a feature is distinctive about an object or agent, it is the most inherent thing about that agent. They never ask why reasoning is more human than emotion, or metabolism.
They never ask why reasoning is more human than emotion, or metabolism.
Yes they do. Nichomachean Ethics I.7, for example. EDIT: but this is also, in part, what the whole of the NE sets out to show: that the best life, and the end of all our activity is a life of the intellect, be it practical or theoretical. So if you're looking for a short argument in the mode of establishing a premise, you're right that there's nothing very satisfying in Aristotle. But the question of what the highest human aim is is hardly a question he ignores. Its the whole subject of his ethical philosophy.
Today's post, Three Fallacies of Teleology was originally published on 25 August 2008. A summary (taken from the LW wiki):
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