1. The Good, the Line and the Cave

2. The Philosopher rulers must know the Good The good is a motivator. Everyone pursues what they believe to be good. The philosopher kings will know what the good is. They will therefore pursue what really is good.

3. A doctor can know medicine, and yet still use that knowledge to poison people A Pilot can know the art of navigation, and use it to run the ship aground. Likewise, the mere knowledge of justice is not by itself going to motivate someone to be or produce justice.

4. You have to know not just what justice is, you need to know that justice is good. Knowledge of the good is distinctive because it motivates behavior. If I know justice is good, then I will want to produce just things (cities) and be a just person.

5. But what is the form of the Good? The Good is to the intelligible world what the sun is to the visible world The sun causes visible things to come into existence (grow), and it also provides light so we can see them The good allows us to “see”, understand, the forms The good is also the cause of the existence of the forms

6. Because the form of justice derives from the Good, we know that justice is good. All the forms are derivied from the good And since the forms cause the structure of the sensible world, the Good is the cause of everything.

7. What about evil? If everything derives from the Good, then it seems everything should be GOOD But everything is not good. How can Plato account for the existence of bad/evil, given that everything derives from The Good.

8. One possibility: Evil is a privation Injustice may not be real property at all Injustice may not be real property at all Just as being blind is the lack of sight, so being bad may be the lack of good. there is no form of injustice, but there are various ways in which a person or city can deviate from the form of justice, become less like the form.

9. The Line The line illustrates the relationship between the intelligible and sensible worlds. In the sensible world, the are both things and images (objects of belief and objects of imagination The objects of imagination are images of the objects of belief (things)

10. The sensible world is an image Likewise the sensible world, ordinary physical things, are images, imperfect copies of the ideal forms.

11. The Cave! The cave also illustrates the sensible and intelligible world. We are all cave dwellers, who take the images of things to be reality

12. Questions about the cave The cave dwellers treat shadows as reality Shadows correspond to imagination How does this correspond to ordinary life? In what way do we confuse imagination with physical reality (which itself is not really “real”)

13. We confuse image with reality when we take physical things to be what we perceive them to be, when we fail to distinguish our perspective on a thing, and the thing itself We confuse imagination for reality when we allow conventional wisdom, the media, To interpret reality for us.

14. Why do the philosophers go back to the cave The cave, the city, needs rulers. The philosophers don’t want to be in the cave (its more fun outside) But they go back because the ought to. This the one place in the Republic where someone clearly acts against their own self interest.

15. The cave illustrates why philosophers make the best rulers Because the philosophers don’t want to rule, they will not compete to rule. Because they know the cave is just a cave, they will not be corrupted by the temptations of cave life (wealth etc) The philosophers have seen reality, they know the forms. So they are able to make the modelsin the cave more like the reality they imitate.