How do Aristotle's ethical theories differ from Plato?

Answer 1

You want this in one answer??? All right. The most important differences are these:

1. For Plato, being good and living a good life don't depend on emotion, but only on understanding. For Aristotle, having the right kind of feelings at the right time in the right way is crucial.

2. For Plato, you can be good/live a good life even if you are deformed, tortured, poor, ... all so long as you don't do wrong. For Aristotle, even the saintly person's life doesn't deserve to be called good if there's too much misery, poverty, or ugliness in it.

3. For Plato you can have a good life even without friends. Not for Aristotle.

4. Plato thinks there are metaphysical properties "Good", "Just",
"Brave" and so on, which have independent and universal existence. Aristotle disagrees.

5. Finally, Plato thinks it is impossible to do wrong if you really understand what you are doing; Aristotle thinks that is nonsense: people willingly do wrong things all the time.

Answer 2

Plato: Human BEINGS
Aristotle: Humans being.
The difference of the plural means a world of difference between these two.