A critical history of Greek philosophy

by W. T. Stace

God, the Creator, the world-designer, finds beside him, on the one hand, the Ideas, on the other, formless matter. First, he creates the World-Soul. This is incorporeal, but occupies space. He spreads it out like a huge net in empty space. He bisects it, and bends the two halves into an inner and an outer circle, these circles being destined to become the spheres of the planets and the stars respectively. He takes matter and binds it into the four elements, and these elements he builds into the empty framework of the World-Soul. When this is done, the creation of the universe is complete. The rest of the "Timaeus" is occupied with the details of Plato's ideas of astronomy and physical [{211}] science. These are mostly worthless and tedious, and we need not pursue them here. But we may mention that Plato, of course, regarded the earth as the centre of the world. The stars, which are divine beings, revolve around it. They necessarily move in circles, because the circle is the perfect figure. The stars, being divine, are governed solely by reason, and their movement must therefore be circular, because a circular motion is the motion of reason.

The above account of the origin of the world is merely myth, and Plato knows that it is myth. What he apparently did believe in, however, was the existence of the World-Soul, and a few words upon this subject are necessary. The soul, in Plato's system, is the mediator between the world of Ideas and the world of sense. Like the former, it is incorporeal and immortal. Like the latter, it occupies space. Plato thought that there must be a soul in the world to account for the rational behaviour of things, and to explain motion. The reason which governs and directs the world dwells in the World-Soul. And the World-Soul is the cause of motion in the outer universe, just as the human soul is the cause of the motions of the human body. The cosmos is a living being.

(b) The Doctrine of the Human Soul.

The human soul is similar in kind to the World-Soul. It is the cause of the body's movements, and in it the human reason dwells. It has affinities both with the world of Ideas and the world of sense. It is divided into two parts, of which one part is again subdivided into two. The highest part is reason, which is [{212}] that part of the soul which apprehends the Ideas. It is simple and indivisible. Now all destruction of things means the sundering of their parts. But the rational part of the soul, being simple, has no parts. Therefore it is indestructible and immortal. The irrational part of the soul is mortal, and is subdivided into a noble and an ignoble half. To the noble half belong courage, love of honour, and in general the nobler emotions. To the ignoble portion belong the sensuous appetites. The noble half has a certain affinity with reason, in that it has an instinct for what is noble and great. Nevertheless, this is mere instinct, and is not rational. The seat of reason is the head, of the noble half of the lower soul, the breast, of the ignoble half, the lower part of the body. Man alone possesses the three parts of the soul. Animals possess the two lower parts, plants only the appetitive soul. What distinguishes man from the lower orders of creation is thus that he alone possesses reason.

Plato connects the doctrine of the immortality of the rational soul with the theory of Ideas by means of the doctrines of recollection and transmigration. According to the former doctrine, all knowledge is recollection of what was experienced by the soul in its disembodied state before birth. It must carefully be noted, however, that the word knowledge is here used in the special and restricted sense of Plato. Not everything that we should call knowledge is recollection. The sensuous element in my perception that this paper is white is not recollection, since, as being merely sensuous, it is not, in Plato's opinion, to be called knowledge. Here, as elsewhere, he confines the term [{213}] to rational knowledge, that is to say, knowledge of the Ideas, though it is doubtful whether he is wholly consistent with himself in the matter, especially in regard to mathematical knowledge. It must also be noted that this doctrine has nothing in common with the Oriental doctrine of the memory of our past lives upon the earth. An example of this is found in the Buddhist Jàtakas, where the Buddha relates from memory many things that happened to him in the body in his previous births. Plato's doctrine is quite different. It refers only to recollection of the experiences of the soul in its disembodied state in the world of Ideas.

The reasons assigned by Plato for believing in this doctrine may be reduced to two. Firstly, knowledge of the Ideas cannot be derived from the senses, because the Idea is never pure in its sensuous manifestation, but always mixed. The one beauty, for example, is only found in experience mixed with the ugly. The second reason is more striking. And, if the doctrine of recollection is itself fantastic, this, the chief reason upon which Plato bases it, is interesting and important. He pointed out that mathematical knowledge seems to be innate in the mind. It is neither imparted to us by instruction, nor is it gained from experience. Plato, in fact, came within an ace of discovering what, in modern times, is called the distinction between necessary and contingent knowledge, a distinction which was made by Kant the basis of most far-reaching developments in philosophy. The character of necessity attaches to rational knowledge, but not to sensuous. To explain this distinction, we may take as our example of rational knowledge such a proposition as that two [{214}] and two make four. This does not mean merely that, as a matter of fact, every two objects and every other two objects, with which we have tried the experiment, make four. It is not merely a fact, it is a necessity. It is not merely that two and two do make four, but that they must make four. It is inconceivable that they should not. We have not got to go and see whether, in each new case, they do so. We know beforehand that they will, because they must. It is quite otherwise with such a proposition as, "gold is yellow." There is no necessity about it. It is merely a fact. For all anybody can see to the contrary it might just as well be blue. There is nothing inconceivable about its being blue, as there is about two and two making five. Of course, that gold is yellow is no doubt a mechanical necessity, that is, it is determined by causes, and in that sense could not be otherwise. But it is not a logical necessity. It is not a logical contradiction to imagine blue gold, as it would be to imagine two and two making five. Any other proposition in mathematics possesses the same necessity. That the angles at the base of an isosceles triangle are equal is a necessary proposition. It could not be otherwise without contradiction. Its opposite is unthinkable. But that Socrates is standing is not a necessary truth. He might just as well be sitting.

Since a mathematical proposition is necessarily true, its truth is known without verification by experience. Having proved the proposition about the isosceles triangle, we do not go about measuring the angles of triangular objects to make sure there is no exception. We know it without any experience at all. And if we [{215}] were sufficiently clever, we might even evolve mathematical knowledge out of the resources of our own minds, without its being told us by any teacher. That Caesar was stabbed by Brutus is a fact which no amount of cleverness could ever reveal to me. This information I can only get by being told it. But that the base angles of an isosceles triangle are equal I could discover by merely thinking about it. The proposition about Brutus is not a necessary proposition. It might be otherwise. And therefore I must be told whether it is true or not. But the proposition about the isosceles triangle is necessary, and therefore I can see that it must be true without being told.

Now Plato did not clearly make this distinction between necessary and non-necessary knowledge. But what he did perceive was that mathematical knowledge can be known without either experience or instruction. Kant afterwards gave a less fantastic explanation of these facts. But Plato concluded that such knowledge must be already present in the mind at birth. It must be recollected from a previous existence. It might be answered that, though this kind of knowledge is not gained from the experience of the senses, it may be gained from teaching. It may be imparted by another mind. We have to teach children mathematics, which we should not have to do if it were already in their minds. But Plato's answer is that when the teacher explains a geometrical theorem to the child, directly the child understands what is meant, he assents. He sees it for himself. But if the teacher explains that Lisbon is on the Tagus, the child cannot see that this is true for himself. He must either believe the word [{216}] of the teacher, or he must go and see. In this case, therefore, the knowledge is really imparted from one mind to another. The teacher transfers to the child knowledge which the child does not possess. But the mathematical theorem is already present in the child's mind, and the process of teaching merely consists in making him see what he already potentially knows. He has only to look into his own mind to find it. This is what we mean by saying that the child sees it for himself.

In the "Meno" Plato attempts to give an experimental proof of the doctrine of recollection. Socrates is represented as talking to a slave-boy, who admittedly has no education in mathematics, and barely knows what a square is. By dint of skilful questioning Socrates elicits from the boy's mind a theorem about the properties of the square. The point of the argument is that Socrates tells him nothing at all. He imparts no information. He only asks questions. The boy's knowledge of the theorem, therefore, is not due to the teaching of Socrates, nor is it due to experience. It can only be recollection. But if knowledge is recollection, it may be asked, why is it that we do not remember at once? Why is the tedious process of education in mathematics necessary? Because the soul, descending from the world of Ideas into the body, has its knowledge dulled and almost blotted out by its immersion in the sensuous. It has forgotten, or it has only the dimmest and faintest recollection. It has to be reminded, and it takes a great effort to bring the half-lost ideas back to the mind. This process of being reminded is education.

With this, of course, is connected the doctrine of [{217}] transmigration, which Plato took, no doubt, from the Pythagoreans. Most of the details of Plato's doctrine of transmigration are mere myth. Plato does not mean them seriously, as is shown by the fact that he gives quite different and inconsistent accounts of these details in different dialogues. What, in all probability, he did believe, however, may be summarized as follows. The soul is pre-existent as well as immortal. Its natural home is the world of Ideas, where at first it existed, without a body, in the pure and blissful contemplation of Ideas. But because it has affinities with the world of sense, it sinks down into a body. After death, if a man has lived a good life, and especially if he has cultivated the knowledge of Ideas, philosophy, the soul returns to its blissful abode in the world of Ideas, till, after a long period it again returns to earth in a body. Those who do evil suffer after death severe penalties, and are then reincarnated in the body of some being lower than themselves. A man may become a woman. Men may even, if their lives have been utterly sensual, pass into the bodies of animals.