-121-
perfectly; it is only owing to this imperfection that there can be many of them. The cat is real; particular cats are only apparent.
In the last book of the Republic, as a preliminary to a condemnation of painters, there is a very clear exposition of the doctrine of ideas or forms.
Here Plato explains that, whenever a number of individuals have a common name, they have also a common «idea» or «form.» For instance, though there are many beds, there is only one «idea» or «form» of a bed. Just as a reflection of a bed in a mirror is only apparent and not «real,» so the various particular beds are unreal, being only copies of the «idea,» which is the one real bed, and is made by God. Of this one bed, made by God, there can be knowledge, but in respect of the many beds made by carpenters there can be only opinion. The philosopher, as such, will be interested only in the one ideal bed, not in the many beds found in the sensible world. He will have a certain indifference to ordinary mundane affairs: «how can he who has magnificence of mind and is the spectator of all time and all existence, think much of human life?» The youth who is capable of becoming a philosopher will be distinguished among his fellows as just and gentle, fond of learning, possessed of a good memory and a naturally harmonious mind. Such a one shall be educated into a philosopher and a guardian.
At this point Adeimantus breaks in with a protest. When he tries to argue with Socrates, he says, he feels himself led a little astray at each step, until, in the end, all his former notions are turned upside down. But whatever Socrates may say, it remains the case, as any one can see, that people who stick to philosophy become strange monsters, not to say utter rogues; even the best of them are made useless by philosophy.
Socrates admits that this is true in the world as it is, but maintains that it is the other people who are to blame, not the philosophers; in a wise community the philosophers would not seem foolish; it is only among fools that the wise are judged to be destitute of wisdom.
What are we to do in this dilemma? There were to have been two ways of inaugurating our Republic: by philosophers becoming rulers, or by rulers becoming philosophers. The first way seems impossible as a beginning, because in a city not already philosophic the philosophers are unpopular. But a born prince might be a philosopher,
-122-
and «one is enough; let there be one man who has a city obedient to his will, and he might bring into existence the ideal polity about which the world is so incredulous.» Plato hoped that he had found such a prince in the younger Dionysius, tyrant of Syracuse, but the young man turned out disappointingly.
In the sixth and seventh books of the Republic, Plato is concerned with two questions: First, what is philosophy? Second, how can a young man or woman, of suitable temperament, be so educated as to become a philosopher?
Philosophy, for Plato, is a kind of vision, the «vision of truth.» It is not purely intellectual; it is not merely wisdom, but love of wisdom. Spinoza’s «intellectual love of God» is much the same intimate union of thought and feeling. Every one who has done any kind of creative work has experienced, in a greater or less degree, the state of mind in which, after long labour, truth, or beauty, appears, or seems to appear, in a sudden glory—it may be only about some small matter, or it may be about the universe. The experience is, at the moment, very convincing; doubt may come later, but at the time there is utter certainty. I think most of the best creative work, in art, in science, in literature, and in philosophy, has been the result of such a moment. Whether it comes to others as to me, I cannot say. For my part, I have found that, when I wish to write a book on some subject, I must first soak myself in detail, until all the separate parts of the subject-matter are familiar; then, some day, if I am fortunate, I perceive the whole, with all its parts duly interrelated. After that, I only have to write down what I have seen. The nearest analogy is first walking all over a mountain in a mist, until every path and ridge and valley is separately familiar, and then, from a distance, seeing the mountain whole and clear in bright sunshine.
This experience, I believe, is necessary to good creative work, but it is not sufficient; indeed the subjective certainty that it brings with it may be fatally misleading. William James describes a man who got the experience from laughing-gas; whenever he was under its influence, he knew the secret of the universe, but when he came to, he had forgotten it. At last, with immense effort, he wrote down the secret before the vision had faded. When completely recovered, he rushed to see what he had written. It was: «A smell of petroleum prevails throughout.» What seems like sudden insight may be mis-
-123-
leading, and must be tested soberly when the divine intoxication has passed.
Plato’s vision, which he completely trusted at the time when he wrote the Republic, needs ultimately the help of a parable, the parable of the cave, in order to convey its nature to the reader. But it is led up to by various preliminary discussions, designed to make the reader see the necessity of the world of ideas.
First, the world of the intellect is distinguished from the world of the senses; then intellect and sense-perception are in turn each divided into two kinds. The two kinds of sense-perception need not concern us; the two kinds of intellect are called, respectively, «reason» and «understanding.» Of these, reason is the higher kind; it is concerned with pure ideas, and its method is dialectic. Understanding is the kind of intellect that is used in mathematics; it is inferior to reason in that it uses hypotheses which it cannot test. In geometry, for example, we say: «Let ABC be a rectilinear triangle.» It is against the rules to ask whether ABC really is a rectilinear triangle, although, if it is a figure that we have drawn, we may be sure that it is not, because we cannot draw absolutely straight lines. Accordingly, mathematics can never tell us what is, but only what would be if. . . . There are no straight lines in the sensible world; therefore, if mathematics is to have more than hypothetical truth, we must find evidence for the existence of super-sensible straight lines in a super-sensible world. This cannot be done by the understanding, but according to Plato it can be done by reason, which shows that there is a rectilinear triangle in heaven, of which geometrical propositions can be affirmed categorically, not hypothetically.
There is, at this point, a difficulty which seems to have escaped Plato’s notice, although it was evident to modern idealistic philosophers. We saw that God made only one bed, and it would be natural to suppose that he made only one straight line. But if there is a heavenly triangle, he must have made at least three straight lines. The objects of geometry, though ideal, must exist in many examples; we need the possibility of two intersecting circles, and so on. This suggests that geometry, on Plato’s theory, should not be capable of ultimate truth, but should be condemned as part of the study of appearance. We will, however, ignore this point.
Plato seeks to explain the difference between clear intellectual
-124-
vision and the confused vision of sense-perception by an analogy from the sense of sight. Sight, he says, differs from the other senses, since it requires not only the eye and the object, but also light. We see clearly objects on which the sun shines; in twilight we see confusedly, and in pitch-darkness not at all. Now the world of ideas is what we see when the object is illumined by the sun, while the world of passing things is a confused twilight world. The eye is compared to the soul, and the sun, as the source of light, to truth or goodness.
The soul is like an eye: when resting upon that on which truth and being shine, the soul perceives and understands, and is radiant with intelligence; but when turned towards the twilight of becoming and perishing, then she has opinion only, and goes blinking about, and is first of one opinion and then of another, and seems to have no intelligence. . . . Now what imparts truth to the known and the power of knowing to the knower is what I would have you term the idea of good, and this you will deem to be the cause of science.
This leads up to the famous simile of the cave or den, according to which those who are destitute of philosophy may be compared to prisoners in a cave, who are only able to look in one direction because they are bound, and who have a fire behind them and a wall in front. Between them and the wall there is nothing; all that they see are shadows of themselves, and of objects behind them, cast on the wall by the light of the fire. Inevitably they regard these shadows
