1. Aristotle’s function argument
Michael Lacewing

2. Eudaimonia and function
Eudaimonia: living well, our final end
But what is this?
Ergon: something’s function or characteristic form of activity (functioning rather than purpose)
An x is a good x when it performs its characteristic activity well
Good eyes see well; good knives cut well; good plants flourish

3. Virtue Arête: a quality that aids the fulfilment of a thing’s ergon
An excellence or ‘virtue’
The focus of an eye; the sharpness of a knife

4. The ‘function argument’
Being rational – guided by reasons – is the characteristic activity of human beings
Not reasoning but doing things for reasons
This is a psychological property, an activity of the ‘soul’ (psyche)
So our virtues will be properties than enable us to do this well
So eudaimonia consists in activity of the soul which exhibits the virtues by being in accordance with (‘good’ or ‘right’) reason (orthos logos)

5. Testing the analysis Is this argument plausible?
There are three types of good:
goods of the mind (e.g. intelligence, courage, etc.)
goods of the body (e.g. strength, health etc.)
‘external’ goods (e.g. wealth, food, etc.).
People generally agree that the goods of the mind are worth more than the others.
Eudaimonia is ‘living well’. The argument spells this out.

6. Testing the analysis
The good life involves virtue, pleasure and prosperity
Virtue: Central to the account. We must act on virtue, not merely possess it.
Pleasure: People find pleasant whatever it is that they love. A virtuous person loves living virtuously.
Prosperity: In order to live virtuously, we will also need a certain amount of external goods.

7. The rational soul Arational part Rational part Growth and nutrition
Desire and emotion
‘responsive to reason’
Reason
‘rational in itself’
Virtues of character
Virtues of intellect