Full Idea
It is not easy to define by rule how, and how far, a person may go wrong before he incurs blame; because this depends upon particular circumstances, and the decision lies with our perception.
Gist of Idea
We cannot properly judge by rules, because blame depends on perception of particulars
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1126b04)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.162
A Reaction
This is a key objection to Kantian approaches to morality. Aristotle does not flatly deny the role of rules (indeed, he is a great endorser of the law), but this shows why virtues of character are a better guide than rules can ever be.