Full Idea
It is the mark of the trained mind never to expect more precision in the treatment of any subject than the nature of that subject permits.
Gist of Idea
Trained minds never expect more precision than is possible
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1094b18)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.65
A Reaction
An excellent remark in the context of moral philosophy. There is a dream that moral principles might derive from pure reason, or consist of a single rule expressible in a few words, but daily life isn't like that, and morality is not likely to be.