Full Idea
In all things the mean is to be commended, while the extremes are neither commendable nor right, but reprehensible.
Gist of Idea
The mean is always right, and the extremes are always wrong
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1108a16)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.105
A Reaction
This is the aspect of Aristotle which Nietzsche hated, as a stultifying conservativism seems to be implied. Elsewhere, though, Aristotle emphasises what is 'appropriate' (e.g. in anger) which allows the possibility of bolder and more exciting actions.