Plato’s Form of Good
Plato believed that the Forms were interrelated, and arranged in a hierarchy. The highest Form is the
Form of the Good, which is the ultimate principle.
Like the Sun in the Allegory of the Cave, the Good illuminates the other Forms. We can see that
Justice, for example, is an aspect of Goodness. And again, we know that we have never seen, with
our senses, any examples of perfect goodness, but we have seen plenty of particular examples which
approximate goodness, and we recognise them as ‘good’ when we see them because of the way in
which they correspond to our innate notion of the Form of the Good.
By Plato’s logic, real knowledge becomes, in the end, a knowledge of goodness; and this is why
philosophers are in the best position to rule. The one who has philosophical knowledge of the Good is
the one who is fit to rule. Plato’s belief in the fitness to rule of the philosopher is sometimes referred to
as the ‘Philosopher King’ (even though Plato himself never used it).
Plato developed his Theory of Forms to the point where he divided existence into two realms. There is
the world of sense experience (the ‘empirical’ world), where nothing ever stays the same but is always
in the process of change. Experience of it gives rise to opinions. There is also a world which is outside
space and time, which is not perceived through the senses, and in which everything is permanent and
perfect or Ideal - the realm of the Forms. The empirical world shows only shadows and poor copies of
these Forms, and so is less real than the world of the Forms themselves, because the Forms are
eternal and immutable (unchanging), the proper objects of knowledge.
Plato's metaphor of the cave
Plato's parable of the cave is a metaphor for ignorance and knowledge.
Imagine, says Plato, a cave in which prisoners are chained in such a way that
all they can see are shadows thrown on a wall in front of them. All they know
of life are these shadows. They would think that these shadows were reality,
having known nothing else. If one of them were freed, and allowed to emerge
into the daylight, he would see things as they are, and realize how limited his
vision was in the cave. He would be quite unwilling to return:
And when he remembered his old habitation, and the wisdom of the
den and his fellow-prisoners, do you not suppose that he would
felicitate himself on the change, and pity them?...you must not wonder
that those who attain to this beatific vision are unwilling to descend to
human affairs; for their souls are ever hastening into the upper world
where they desire to dwell. (Republic VII, 516)
Yet to his fellow-prisoners, he would seem the fool, not they:
And if there were a contest, and he had to compete in measuring the
shadows with the prisoners who had never moved out of the den, while
his sight was still weak, and before his eyes had become
steady...would he not be ridiculous? Men would say of him that up he
went and down he came without his eyes; and that it was better not
even to think of ascending. (Ibid, 517)