1. Plato, knowledge and virtue
Michael Lacewing
© Michael Lacewing

2. The Form of the Good
The highest knowledge is knowledge of the Form of the Good: it is from the good that ‘things that are just and so on derive their usefulness and value… Is there any point in having these other forms of knowledge without that of the good…?’ (505a-b)

3. The simile of the sun The visible world The intelligible world The sun
The Form of the Good
The eye
The mind (reason)
Sight
Intelligence
To see
To know
Light
Truth
Growth
The being (reality) of the Forms

4. The Form of the Good
Just as sun is the source of light and the source of sight, the Form of the Good ‘gives the objects of knowledge [the Forms] their truth and the knower’s mind the power of knowing’ (508a).
Just as the sun is cause of growth, the Form of the Good is the source of the very being of knowable objects (509b)
Reality is related to goodness: knowledge of what something is is knowledge of what it is for it to be a good example of its kind.

5. Philosophers and virtue
Philosophers love wisdom (philo-sophia)
Therefore they love all learning
Therefore they are not content with appearances, but seek reality
Knowledge and the Form of the Good
Form of the Good is source of reality
To understand what is, is to what it is to be good of its kind

6. Are philosophers virtuous?
How does the philosopher become good? Why would knowledge alone make one good?
To see the Forms, one’s whole mind must be turned around
The love of wisdom removes all other distractions and temptations: ‘if a man’s desires set strongly in one direction, they are correspondingly less strong in other directions’ (485d)

7. Virtue and knowledge
If you know goodness, you will be good.
The philosopher ‘assimilates’ himself to what he enjoys, viz. the Form of the Good.
How does such abstract knowledge help practically? Plato never says.
Plato argues that philosophers are prone to corruption, influenced by praise.
So philosophy only produces virtue in a virtuous society.