V PLATO AND ARISTOTLE

Socrates became the father of many philosophic schools. His pupils naturally differed from one another in the emphasis which they gave to this or that side of their master’s teaching and in the ways in which they combined his doctrines with principles laid down by earlier thinkers, but all agreed in this, that they directed their attention to man as the center of thought and inquiry. From this time ethics and religion became the dominant themes of philosophy. Our subject bids us confine our attention to the greatest of these pupils, Plato.

Plato was born at Athens in the year 428/7 b.c. of an ancient family, which was related to the law-giver Solon. After being educated in the best Athenian fashion, he attached himself to Socrates in his twentieth year, when the latter was already about sixty years old, and he continued to associate with his master for ten years until the latter’s condemnation and death. Probably he was not one of the inner circle, but he tells us that he was present at his master’s trial and with other followers of Socrates was prepared to go bondsman, if a fine were inflicted. Sickness prevented him from sharing in the discussion of the last day, which is related to us in the Phaedo. After Socrates ’ death, Plato was absent from Athens for about twelve years, residing first in the neighboring city of Megara, where his association with Euclides, one of Socrates’ oldest pupils, must have contributed to the development of his own philosophy. Later in southern Italy, if we accept the traditional account of his travels, he had an opportunity to study more closely in their home the Orphic-Pythagorean systems and doctrines, many of which no doubt he had often heard Socrates discuss. At Syracuse in Sicily he won over Dion, the young brother-in-law of the tyrant Dionysius. The latter, however, found his moral teachings offensive, seized him, and had him offered for sale as a prisoner of war in the slave market at Aegina. But a friend, Anniceris, bought him and set him free. When Plato’s other friends wished to repay to Anniceris the money he had spent, the latter refused, and the sum was used to purchase a grove sacred to the hero Academus, in which Plato opened a philosophic school. There, save for the interruptions caused by two journeys to Sicily, he continued to teach for about forty years, dying in 347 b.c. at the age of eighty.

To this school came pupils from almost every part of the Greek world. The chief subjects studied were the various branches of mathematics—including of course astronomy and harmonics,—and dialectics, by which is meant “the art of question and answer, the art of giving a rational account of things and of receiving such an account from others.” The distinctive methods employed were those of analysis and division which Plato seems to have developed so far that the invention of the former was actually, but erroneously, attributed to him. The purpose of analysis was to secure an explanation or proof of a proposition; that of division was to arrive at a proper classification or division of the object under consideration. Plato’s instruction was evidently given in considerable part by lectures, of which his hearers took notes; there was also scientific research on the part of the pupils who worked out the problems or difficulties set them by their master. Nor were these researches wholly mathematical and astronomical, for there is good reason to believe that studies in natural history were also pursued. Indeed, Aristotle, for twenty years a member of the Academy, must have had opportunities here to carry on those researches which interested him most in the early part of his life. But whatever the studies, the purpose was to lead the pupils to the discovery and contemplation of Reality, of Being, of the fundamental and permanent as against the individual and transitory phenomenon. Of Plato’s lectures we know virtually nothing; his Dialogues represent those parts of his doctrine which he wished to give to the outside world; it is probable that they in no sense adequately reproduce his teachings to his disciples.

How much of his philosophy Plato received from his master Socrates, how much he developed for himself cannot now be determined. Socrates left no writings; we know him only from the writings of others, and above all from the dialogues of Plato. There he is the chief spokesman, who leads his associates along various paths toward truth; and certainly no pupil ever built a nobler monument to his teacher than Plato did. Among modern scholars there are many views as to the extent of Plato’s debt to his master: one extreme wing, which has many adherents, would limit the Socratic elements in the Platonic doctrine to the ethical interest, the search for universals, and the dialectic method; the other wing, of which the eminent English Platonist Burnet is the chief representative, would attribute to Socrates practically everything found in the dialogues which Plato wrote before he began his teaching in the Academy. Indeed Burnet holds that Plato’s chief purpose in the earlier dialogues was to set forth the life and teaching of Socrates; he therefore claims that the “doctrine of ideas,” with all its consequences, and much besides, are purely Socratic, taken over by Plato in developed form. Few of us can accept either of these extreme views; it seems more probable that the truth lies between, that Plato learned much relating to “ideas” and their Pythagorean origins from his teacher, just as he derived from him his ethical interest and his method. But to reduce the brilliant pupil to a mere reporter of his master’s views with little philosophy of his own until he was past forty, is quite incredible, and such a procedure has no proper warrant. When speaking of Socrates in my previous lecture I avoided this question, for a discussion of it there would have been unprofitable and confusing; and even now for convenience I propose to treat that part of Plato’s philosophy which immediately concerns us as if it were wholly his own, begging you, however, to keep in mind always that undoubtedly much in germ or developed form was derived directly from Plato’s chief teacher. Furthermore I must ask you to remember that Plato had been given to poetry when a youth, and that although he renounced the practice of the art, he remained a poet in spirit to the end of his life; all his thoughts were touched with poetry, enlivened with humour, and fired with religious zeal. He was a consummate literary artist, and a man of many sides. It was natural therefore that he should nowhere set forth a crystallized system of philosophy such as a less imaginative and duller person might have done; he was apparently a man who grew through all his eighty years. The result is that in spite of the fact that we may properly speak of “the unity of Plato’s thought,” we find in his works variety, variation, and even contradiction. The requirements of our present situation, however, force us to consider our themes categorically, though that procedure is somewhat unfair to Plato.

Let us then first examine the central thought of Plato’s philosophy—the “doctrine of ideas.” Developing the doctrines of earlier philosophers, especially those of Heraclitus and Anaxagoras, Plato held that the world is dual. In it is the phenomenal world visible to us, which includes all natural objects and those made by man, a transient and unreal world which we know only through our senses. But beside it, or rather behind it, is another world invisible but permanent and real, which can be grasped only by the reason. This is the world of ideas. Yet the two worlds are not separate, for the world of the senses owes its existence wholly to its dependence on the world of ideas. To understand Plato’s view we must consider in an elementary way what he meant by “ideas.” The words which he uses (εἶδος, ἰδέα) signify “form,” and in logic are used in the sense of “class,” “kind,” “species,” “the general principle for the classification of objects.” The translation “idea” is traditional, and there is no adequate reason for preferring “form” or any other English equivalent. Now Plato’s statement that the world of phenomena depends on the invisible world of ideas seems at first sight paradoxical, for by it he means that the individual tree, book, desk, chair, good man, or whatever you please, is not the real being at all, but that the ideas of tree, book, desk, chair, and goodness alone possess reality. It may be made plain by an illustration which shall be Plato’s own. At the beginning of the tenth book of the Republic Socrates and Glaucon are conversing together. The master wins Glaucon’s assent first to the proposition that although there are many beds and tables in the world, there are only two ideas, one of a bed, the other of a table. He then goes on to show that the workman makes a bed or table by shaping his material according to the idea of a bed or a table, but that he does not create the ideas themselves. That is done by God who is the real maker of the real bed, that is, of the idea of a bed. The carpenter makes only the particular bed which owes its temporary existence to the eternal idea—the real bed—which is in Nature, in the mind of God. Or if Plato should appear before us tonight, he might say, “Suppose we take a dozen books of different sizes and different shapes and appearance, how do we recognize that these diverse objects are all books?” Then when we hesitated to give an answer, as we probably should, he would reply, “It is because each one of these individual books partakes of the idea of book. The idea is present in the individual example and thereby gives the individual its existence; the individual depends therefore on the idea, not the idea on the individual. If this dozen, or indeed if all the books in the entire world were to be destroyed, the idea of book would still remain, and new books could be made by causing the materials, out of which books are constructed, to partake of the idea of book. That is, all individual books are transitory, impermanent, unreal; the idea of book is permanent, eternal, it alone has reality; and all individual things, therefore, exist, so far as they have any real existence, only by partaking of the ideas. So all things come into being and owe their existence to sharing in the eternal ideas.”

We should be unjust to Plato if we thought that he regarded this doctrine as a perfect explanation of the relation between the visible and invisible worlds. Far from holding such a view he himself evidently held it to be a “guess at truth,” which served to show in its way that there is a permanent reality behind the phenomena of the visible world and a truth which is beyond sense. Indeed Plato is very conscious of troublesome questions which arise in connection with the doctrine, and in three dialogues—his Philebus, Parmenides, and Sophist—he endeavors to meet some of these questions, and there he offers admirable criticism of his own views.

With reference to the source of the doctrine, as I have said above, we cannot tell how much Plato derived from Socrates or how much he developed for himself. Socrates was evidently always searching for universals, trying to determine what goodness is in itself in contrast to the goodness embodied in a good man, what are virtue, courage, and such qualities. The teacher or the pupil may have extended the ideas, the universals, to include all things, even the humble articles of furniture which are the examples in the Republic. But in any case by this doctrine of “ideas,” “forms,” Plato secured a basis for reality, a means of attaining absolute knowledge in contrast to that relative knowledge, which according to the Sophists was the utmost which man could attain. Plato would have quite agreed with Protagoras that if the senses were our only avenues to knowledge, then indeed man would be the measure of all things and his knowledge would be limited to the transient phenomenal world; that is, he could have no knowledge of reality; but by apprehending through our reason the ideas—that is, the realities—on which the phenomenal world depends, we can gain genuine knowledge and free ourselves from subjection to mere opinion.

Plato also teaches that there are various grades of ideas, some being subordinate to others; the highest of all is that of the Good, identified by him with the Beautiful. This supreme idea is at once the cause of all existence and knowledge, and comprehends within itself all other ideas; as the sun in the visible world, so in the world of true knowledge the Good “is the universal author of all things right and beautiful, itself the source of truth and intelligence.” It is the Absolute, the universal Reason, God.[190]

We have seen that Plato sets the world of ideas apprehended by reason over against the world of phenomena, known to us through our senses. The latter world is material, the former immaterial. This concept of the immateriality of ideas was something new in philosophy. Anaxagoras had thought his formative principle (Νοῦς), as his predecessors had thought theirs, to be as material as the “seeds” out of which all things were made; but Plato developed an immaterial, an ideal world, wherein are found all cause and all reality.

Now the Platonic ideas are apprehended by the human intellect. What are the consequences of this fact? It must follow that man’s reason has a nature similar to that of the ideas; like them it must belong to the world which is above the senses; and with them it must partake of the Absolute. But Plato shows that the ideas are eternal and immortal, and draws therefrom the logical conclusion that man’s intellect, his reasoning soul, likewise knows no creation and is free from death.

However he is not content to let the matter rest on this argument alone, but he supports the doctrine of immortality by many proofs, as in the Phaedrus where Socrates explains: “The soul through all her being is immortal, for that which is ever in motion is immortal; but that which moves another and is moved by another, in ceasing to move, ceases also to live. Only the self-moving, as it never leaves itself, never ceases to move and is the fountain and beginning of motion to all that moves besides.”[191] In the Phaedo[192] he represents Socrates as offering a number of different arguments to his questioning friends. One of these is that by which he first proves that souls exist before they are domiciled in our bodies, for recollection implies a previous existence, and since men can recall and recognize things which they have never seen or been taught in their present existence, it follows that they have been born with this knowledge, so that what we call learning is after all only a recollection of ideas gained in a previous existence. Socrates concludes his argument with the question: “Then may we not say, Simmias, that if, as we are always repeating, there is an absolute beauty, and goodness, and an absolute essence of all things; and if to this, which is now discovered to have existed in our former state, we refer all our sensations, and with this compare them, finding these ideas to be pre-existent and our inborn possession—then our souls must have had a prior existence, but if not, there would be no force in the argument?” To this his hearers give ready assent. In the Meno this same argument is very adroitly drawn from the realm of mathematics.[193] An untutored slave is made to “recollect” that the square of the hypothenuse of an isosceles right-angled triangle is equal to twice the square of one of its sides. This is the doctrine of recollection to which Wordsworth has given beautiful expression in his familiar lines:

Our birth is but a sleep and a forgetting: The soul that rises with us, our life’s star, Hath had elsewhere its setting, And cometh from afar; Not in entire forgetfulness, And not in utter nakedness, But trailing clouds of glory do we come From God, who is our home.

But as Simmias and Cebes in the Phaedo point out, this doctrine only shows that the soul existed before the body; it does not prove that the soul is immortal. Socrates therefore goes on to prove this further point, largely by showing the simple and unchanging nature of the soul which is like that of the ideas, and he therefore concludes that since it cannot admit of change, it must be free from death. Again he argues that since the soul can rule and use the body as it will, it must be anterior to the body and hence have an eternal and never ending existence.[194] The final and apparently most convincing proof to Plato’s mind, in spite of its dialectic character, is that the notion of life cannot be separated from the soul, for the soul is that which gives life; therefore since a dead soul is an impossibility, we must agree that the soul is immortal.[195] To follow out in detail the other arguments would occupy too much time now, interesting as it might prove. Indeed if we were to rehearse all of Plato’s proofs of the immortality of the soul, we should run through practically the entire gamut of the arguments which have ever been offered. His frequent return to the subject indicates the importance which he gave to the belief.

Before we approach Plato’s ethical and religious views we must glance for a moment at his psychology, for on that depends in no small measure his moral system. In the fourth book of the Republic when discussing the different forms of government, Socrates is made to show that the soul has three parts or elements: the first is the divine or rational part (τὸ θεῖον, τὸ λογιστικόν) whose seat is in the head, the second, the courageous or passionate element (τὸ θυμοειδές) residing in the heart, and the third is the appetite (τὸ ἐπιθυμητικόν) which belongs to the diaphragm or liver.[196] In the Phaedrus[197] this same division is set forth in a myth. Now when in an individual all three parts are in accord under the leadership of reason, whose orders are enforced by courage on appetite, the man is virtuous; but if appetite and courage unite against reason, discord results and the man is vicious. As the state is well ordered when harmony exists among its parts, so harmony of the soul, led by the reason, produces the virtuous human being. In the earlier dialogues the soul is evidently regarded as a unit, so that the parts are really forms or manifestations of the soul; all three are immortal. But in the Timaeus only the reason is immortal, the other parts being separable and bound to the body with which they die.[198] Now we have already seen that the soul, or at least its rational part, being divine and immortal, has an affinity for the eternal ideas and is endowed by a natural love for the true, the beautiful, and the good. It is therefore impelled toward the divine world of ideas by a natural passion, and this effort on the part of man’s reason is philosophy. The true philosopher then is the lover of truth and reality, who is absorbed in the pleasures of the soul so that he will hardly be conscious of bodily pleasure; indeed he will not think much of human life or even fear death.[199] The soul, however, in its effort to mount into the realm of the ideas, is held back by the body in which it is imprisoned and fettered in the world of the senses. Thus we find in Plato the Orphic belief that man has a dual nature, made up of a divine soul and a mortal hindering body. We shall presently see how he gave to the emotional belief of that sect a philosophic basis and so transformed it into a reasonable article of morality and religion.

Now we may consider Plato’s moral and religious views. The highest good for man, according to his teaching, is likeness to God—that is, the largest possible participation in the ideas of the Good which are in the Absolute. In direct proportion to the success of the rational soul in appropriating to itself these ideas, the man will practise justice and holiness, that is, be righteous; but inasmuch as the world of ideas cannot be apprehended by the senses, the rational soul of the philosopher must always try to escape from the world of the senses where evils dwell. As Socrates in the Theaetetus[200] assures Theodorus: “Evils, Theodorus, can never pass away; for there must always remain something which is antagonistic to the good. Having no place among the gods in heaven, of necessity they hover around the mortal nature and this earthly sphere. Wherefore we ought to fly away from earth to heaven as quickly as we can; and to fly away is to become like God, so far as this is possible; and to become like him is to become holy, just, and wise ... God is never in any way unrighteous—he is perfect righteousness; and he of us who is the most righteous is most like him.... To know this is true wisdom and virtue; and ignorance of this is manifest folly and vice.” The man, then, whose soul strives to become like God will inevitably be righteous. Plato’s philosophy thus results in practical morality.

Furthermore we are assured in the Republic that a seeker after righteousness will not be neglected by the gods, for Socrates there says:[201] “Then this must be our notion of the just man, that even when he is in poverty or sickness or any other seeming misfortune, all things will in the end work together for good to him in life and death: for the gods have a care of any one whose desire is to become just and be like God, so far as man can attain the divine likeness, by the pursuit of virtue.”

The path by which man is to attain to likeness of God, and so to freedom from his lower nature, is that of a noble asceticism which Socrates described to Simmias and Cebes the night before his own death:[202] “No one who has not studied philosophy and who is not entirely pure at the time of his departure is allowed to enter the company of the gods, but the lover of knowledge only. And this is the reason, Simmias and Cebes, why the true votaries of philosophy abstain from all fleshly lusts, and hold out against them and refuse to give themselves up to them, not because they fear poverty or the ruin of their families, like the lovers of money and the world in general; nor like the lovers of power and honour, because they dread the dishonour or the disgrace of evil deeds.”

“No, Socrates, that would not become them,” said Cebes.

“No indeed,” he replied, “and therefore they who have any care of their own souls, and do not merely live moulding and fashioning the body, say farewell to all this; they will not walk in the ways of the blind: and when philosophy offers them purification and release from evil, they feel that they ought not to resist her influence, and whither she leads they turn and follow.”

“What do you mean, Socrates?”

“I will tell you,” he said. “The lovers of knowledge are conscious that the soul was simply fastened and glued to the body—until philosophy freed her, she could only view real existence through the bars of a prison, not in and through herself; she was wallowing in the mire of every sort of ignorance, and by reason of lust had become the principal accomplice in her own captivity.” And a little later Socrates says: “The soul of the true philosopher thinks that she ought not to resist this deliverance (which philosophy offers), and therefore abstains from pleasures and desires and pains and fears, so far as she is able.”

Somewhat earlier in the dialogue Socrates had stated in still more emphatic terms the necessity of putting the body aside if man’s soul would attain real knowledge:[203] “For if while in company with the body the soul cannot have pure knowledge, one of two things follows—either knowledge is not to be attained at all, or if at all, after death. For then, and not till then, the soul will be parted from the body and exist in herself alone. In this present life, I reckon that we make the nearest approach to knowledge when we have the least possible intercourse or communion with the body, and are not surfeited with the bodily nature, but keep ourselves pure until the hour when God himself is pleased to release us. And thus having got rid of the foolishness of the body we shall be pure and shall hold converse with the pure, and know of ourselves the clear light everywhere, which is no other than the light of truth.” As the phrase, “until the hour when God himself is pleased to release us,” shows, man might not hasten the time of his release by his own act. And in other places, in familiar ways, Plato teaches that man may not desert the station where god has set him on guard until the command is given.

Finally in the Cratylus,[204] where Socrates in discussing the origin and nature of language indulges in some serious fooling in connection with the name of the soul (ψυχή), he says that he imagines that those who first gave the soul its name “psyche,” (ψυχή), wished to express the truth that the soul when in the body is the source of life, and gives the body the ability to breathe and revive, and that when this power fails the body, then it perishes and dies. As for body, he reminds his interlocutor that that word (σῶμα) is variously interpreted, some saying that it is the grave (σῆμα) of the soul, which may be regarded as in a tomb during this present life; and he adds that the Orphic poets were probably the ones who invented the name, for they had the notion that the embodied soul is suffering punishment for sin, and that the body is a prison in which the soul is incarcerated until the penalty of sin is paid. Likewise in the Gorgias[205] Socrates refers to the same Orphic idea and quotes a verse from Euripides: “Who knows whether life be not death and death life?” That is, this death in life is due to the body which tends to strangle the soul. Only when the reasoning soul has escaped from this tomb of the flesh can it really live. This is the reason why the true philosopher is always pursuing death in the sense that he is trying to free his soul, so far as may be, from the concerns of the body that it may enjoy life at its best.[206]

I have used Plato’s own words thus extensively for they set forth more eloquently than any words of mine the essential features of his doctrine. It requires no argument to show how great his debt to the Orphics and Pythagoreans was. But we cannot fail to see that he went far beyond his predecessors, for to their emotional belief in the immortality of the soul he gave an intellectual basis, by showing that the rational soul is of the same nature and substance as the Absolute, and therefore immortal and ever striving to apprehend the Absolute to which it belongs. In place of the external purifications and simple taboos which made up the Orphic course of life, Plato substitutes a noble discipline, reminding us of St. Paul—a discipline which has for its aim nothing less than the likening of man’s soul to God. When Plato teaches that man must begin his immortality here “by the practice of death,” we now see that he really means the practice of life; for life can only begin when the soul is released from its bodily tomb.

From the Orphics and Pythagoreans Plato adopted also the doctrine of the transmigration of souls. According to his view a thousand years—ten times the longest span of human life—elapsed between death and rebirth, during which the wicked received their ten-fold punishment and the righteous their like reward. When the time to return on earth came around, the souls were allowed to choose their new life as they pleased, only the wicked souls, “which had never seen the truth,” could not pass into the bodies of men. The choice made and their next destiny determined, the souls passed to the plain of Forgetfulness where each must drink of the river of Lethe; in the darkness of midnight there was an earthquake and thunderstorm, and the souls were driven, like shooting stars, to their birth. Ten thousand years were required to complete the round of rebirths and to allow the soul to return to its heavenly home. But the soul of a philosopher, “guileless and true,” might secure release after three rebirths if each time he had chosen the higher life. Some incurable sinners were not allowed to return to earth, but when their souls approached the mouth of the cavern which led to the upper world, the mouth gave a mighty roar and drove them back, while fiends tortured them with all the sufferings which a fertile imagination could devise. The path of salvation therefore lay in following righteousness and justice, in choosing the good, that is, in true philosophy. At the close of the Republic Socrates relates the vision of Er the Pamphylian whose soul returned with a report of the other world, and so concludes: “And thus, Glaucon, the tale has been saved and has not perished, and will save us if we are obedient to the word spoken; and we shall pass safely over the river of Forgetfulness and our soul will not be defiled. Wherefore my counsel is, that we hold fast ever to the heavenly way and follow after justice and virtue always, considering that the soul is immortal and able to endure every sort of good and every sort of evil. Thus shall we live dear to one another and to the gods, both while remaining here and when, like conquerors in the games who go round to gather gifts, we receive our reward. And it shall be well with us both in this life and in the pilgrimage of a thousand years which we have been describing.”[207]

With regard to the ultimate fate of the soul Plato is not wholly clear; but apparently he held that with the exception of those who had done unpardonable wrongs the souls of men, when their wanderings and rebirths were over and they had attained to purity, returned to God, to the universal reason; probably, however, he thought of their return as being without loss of individuality, for Plato lays so much stress on the individual soul that we cannot believe that he would have allowed it to lose its personality in the Absolute.

This account, I trust, for all its imperfections, is sufficient to indicate what a great advance Plato made in his concept of the spiritual life. Man’s reason is now made the means and agent of his spiritual ascent; the reasoning soul, by its own nature, strives to seek its own, and so finds its goal by virtue of its reason. The human will is not neglected in the Platonic system, but it is by no means made prominent. Man’s salvation is attained when the soul through the exercise of its reason has risen superior to its bodily prison, freed itself of the imperfections and evils which are necessarily associated with the body, and purified has attained to God’s likeness.

In the preceding discussion I have used the word God freely, but it may fairly be asked how far such use is justified, and furthermore whether Plato was a pantheist or a polytheist. It is indeed somewhat difficult to answer these questions, for in many passages he speaks of the gods in the plural after the common manner, and in the Timaeus he especially provides for a multitude of gods secondary to the Absolute; in many other places he speaks of the Divine (τὸ θεῖον) or simply God (θεός). Sometimes he seems to conceive of God as a living personality; again God is apparently only the impersonal idea of the Good. Yet in spite of the fact that his expressions range from polytheism almost to monotheism, considering the sum total of his thought, we are justified in speaking of his idea of God. At the same time we must always understand that his thought admitted many gods, subordinate to the Absolute and included in it.

But whatever the form of expression which he uses, Plato conceives of God as the giver of good alone. For him there is no deception or deceit in the divine; the chastening of man by God is always for the purpose of making man better, never to satisfy any punitive desire. The notion of “the envy of the gods,” which is so prominent in Aeschylus, Herodotus, and other writers of the fifth century, to Plato is abhorrent and inconceivable. Furthermore he makes the Divine, the idea of the Good, the measure of truth, not man, as Protagoras would have had him. His world therefore has a divine warrant of its validity; it is ordered by the mind of the good and just God, and not by the will of a debased divinity or by mere chance. Previous thinkers had made Justice the highest attribute of divinity; to this Plato added Goodness as the chief characteristic of God.

But in this discussion of Plato’s religious philosophy we have left one important subject untouched—the problem of evil. This was a question which a mind so acute and inquisitive as Plato’s could not finally avoid. Of the presence of evil in the world he was fully aware, and indeed he maintained that evils must always exist, for there must remain something antagonistic to the good; and since evils cannot exist in heaven the earth is their abode, from which man must try to escape.[208] On the source of evil, however, he touches only in the Statesman and the Timaeus;[209] in both the question is intimately connected with his theories of creation, which he sets forth in myth. But leaving aside the Platonic imagery, I will simply remind you that earlier in this lecture we saw that Plato conceived the world we know as dual—the phenomenal world known through the senses and the world of ideas apprehended by reason. Now the ideas alone have Being; but the phenomenal world is always in a state of Becoming, that is, of coming into being and of ceasing to be; it is both temporal and imperfect. Obviously there must be some principle, parallel in a way to the perfect and eternal ideas, such that it can receive them, and by its participation in them bring the imperfect sensible world into transitory existence. This principle is to Plato the material element. Now since he ascribes to the ideas alone real existence, that is, Being, the material principle must be Not-being. It is the negative substratum of all sensible phenomena, itself invisible, without form or characteristic, or in Plato’s words “the receptacle, and in a manner, the nurse of all generation” for, although itself formless, it is capable of taking on all the forms which the ideas may impose upon it. Plato himself could not avoid the difficulties which such a material substratum raises, and at times he is forced to speak as if it were something real in itself, having an existence beside the ideas. But his true notion seems to be that matter is mere negation, like the Aristotelian στέρησις, something which cannot be grasped by the intellect, as can the ideas, or perceived by the senses, as can the phenomenal world; it is identical with space. Of course when Plato talks about this negative principle, he inevitably speaks as if we could know something about it.[210]

The Absolute in Plato’s thought had not only life and intelligence but also creative activities; and the acts of creation consisted in imposing on the formless material principle the ideas which the Absolute comprehends in itself, or, as perhaps he would have preferred to say, in making the material principle partake of the appropriate idea. In the Cratylus he illustrates the relation of matter to the idea by the way in which the artisan makes a shuttle out of wood, always forming his material with reference to the true or ideal shuttle.[211] We may illustrate further by examples modelled on Plato’s own. Think for a moment of the potter and his clay. The clay is formless matter which the potter takes and places on the wheel, and there imposes upon the clay the idea of the pot which is in his own mind; so the pot acquires a real existence in so far as it partakes of or embodies the idea which exists in the potter’s mind. Or we may think of the sculptor and the shapeless block of marble. By imposing his idea upon the marble, by making the shapeless block embody his idea, the sculptor brings the statue into being. These illustrations, both Plato’s and my own, are of course misleading, for the wood, clay, and marble from which the several objects are made are far from being the negative substance which Plato would have us believe his material principle to be. But they may serve to suggest the way in which he conceived the varied world about us to come into its temporary existence.

Now to Plato’s mind the Absolute and the ideas are perfect; yet we know that the phenomenal world is imperfect, and imperfection is evil; therefore, he says, evil must be found in the negative substratum, since as we have already seen, this was regarded by Plato as in every way the opposite of the perfect ideas. This imperfection, inherent in the material principle, is the “necessity” of which he speaks in the Theaetetus as causing evils—the opposite of the good.[212] Evil, therefore, is eternal, but, as we have earlier learned, the individual may escape, if he will take the deliverance which philosophy offers him.

As I have said, the course of creation is explained through myth in the Timaeus and the Statesman.[213] In the former God is represented as creating first the gods of heaven which are the fixed stars and planets, from whom sprang the gods of popular mythology. The Creator had already conceived of creatures of the air, sea, and land; but these he did not himself create, for then they would have been on equality with the gods; he rather commissioned the gods to create man and the lower animals, while he furnished the divine part, the soul. Man’s soul therefore is of the same nature as the universal soul, but his body is material, made of the four elements of earth, air, fire, and water, and it is imperfect, being subject to the passions. In the Statesman Plato sets forth his theory of the development of man from an earlier stage to the present: the significant thing for us at the moment is his explanation of man’s falling away from virtue as due to the admixture of matter in him, that this fall was “inherent in the primal nature which was full of disorder.”

This, then, will at least suggest Plato’s view as to the origin of evil in the world. His language is that of myth, and it seems evident that he did not formulate his explanation perfectly even in his own mind. We shall best regard it as one of his guesses at truth. It is, of course, easy to find weaknesses in his thought on this question and to show that the explanation which he suggests is not satisfactory. But we shall do better to remember the difficulty of the problem and to recognize the value of his attempt to reach its solution.

The greatest service, however, which Plato did was to establish by means of his doctrine of ideas a rational relation between the invisible world of reason and the visible world of the senses; and by pointing out that the rational part of man’s soul is of the same substance as the ideas and therefore of the same substance as the Absolute, to give an intellectual basis to the doctrine of a natural striving on the part of man after the supreme Good. Hardly second to this was his service in the field of ethics, where he showed that man’s spiritual advance depends upon the constant curbing of the passions and the body. The greatness of his genius is shown by the fact that throughout antiquity the highest religious thought of paganism had its source in his work and was only a development of it. Before we have finished these lectures we shall gain some hints of his profound influence on Christianity.

Platonic philosophy by attributing to the ideas an existence apart from things, and conversely by denying all existence to anything but the ideas, had removed all reality to the supernatural world. It was inevitable that this view should be promptly attacked. The challenge came from Plato’s greatest pupil, Aristotle.

Aristotle, born at Stagira in Thrace about 384 b.c., by inheritance and early training had a strong bent toward natural science, since he was descended from a line of physicians who, according to Galen, taught anatomy by dissection. For twenty years he was the pupil and assistant of Plato in the Academy. After the death of his master he went to the court of Hermias, a prince of Mysia, and in 343 he was appointed tutor to the son of King Philip of Macedon, Alexander, then thirteen years of age. About 335 he opened a school in the Lyceum at Athens, where he taught for some thirteen years. Then, being accused of impiety after Alexander’s death, he withdrew to Chalcis in Euboea, as he said, that the Athenians might not sin a second time against philosophy; there he died about 322.

Into Aristotle’s encyclopedic knowledge and enormous scientific activities we may not now go; and indeed we need not dwell at very great length upon him, for his influence in religion was less potent than Plato’s through antiquity and the earlier Middle Ages. The chief cause of the elder philosopher’s greater influence is to be found in the fact that Plato’s thought centered on man, his morality, and his relation to God, while Aristotle was concerned primarily with the universe of which man was to him only a part; to Plato virtue was inseparably connected with religion, and was therefore something to be sought with fervent spirit as well as with cool reason; to Aristotle virtue was rather an intellectual matter, an even balance of the soul, that natural perfection of the whole organism on which the well-being and happiness of man depended—a state which was to be attained by right calculation, choice, and habit. So it came to pass that although Aristotle’s works on logic were continuously studied in one form or another, his great sway in many realms of human thought, including theology, began in the thirteenth century, when, learning first from Arabic scholars, later aided and stimulated by the Latin conquest of Constantinople in 1204, the western intellectual world eagerly studied his works anew. Then Albertus Magnus, St. Thomas Aquinas, and Roger Bacon raised him to the supreme position in philosophy and theology, so that he became for that age indeed “the master of those who know.”

Let us now consider some parts of his philosophy. He criticized Plato’s doctrine that ideas have an existence apart from things, and not unjustly charged that Plato had taken the universals, which we arrive at by abstraction, and had elevated these general concepts into eternal and immortal elements, claiming for them that they were anterior to the things of sense and alone had real existence. In his own philosophy he took a position fundamentally opposed to that of Plato, for he insisted that “ideas,” “forms” and the phenomenal world could not exist apart, for if they did, then we should be obliged to postulate a third world beyond them; that is to say, that if the idea of man, for example, had a substantial existence apart from individual men, then there would have to be an idea antecedent to both the idea of man and the individual men, the model of both, and this idea would be a “third man.” He further pointed out that men know the ideas only in the concrete objects, never apart from those objects of which they are the ideas, that the essence can never be separated from that of which it is the essence, since then both thing and essence would cease to exist. So he charged Plato with using meaningless poetic metaphors when he said that ideas, forms, existed apart from things. Reality to Aristotle was always in the individual object, itself an indissoluble union of matter and form. Of course he recognized that the human mind could abstract these two elements each from the other and could think of the matter and the form as separate, but he would not allow that these abstractions had substantial reality in the sense that they could ever exist by themselves.[214]

Since then to him the Platonic ideas were nothing apart from the individual objects, Aristotle could find no principle of movement or change in them; so he claimed that the doctrine of ideas was sterile and came to naught. In his own system he enumerated four principles or causes, which he insisted, however, are only known to us from individual things: the material cause (τὸ ἐξ oὗ γίνεταί τι, ἡ ὓλη), the formal cause (τὸ εἶδος, ἡ μορφή), the efficient cause (τὸ ὅθεν ἡ ἀρχή), and the final cause (τὸ oὗ ἕνεκα, τὸ τέλος). To make his meaning clear let us use in part his own illustrations: the material cause of the statue is the bronze of which it is made, just as in the example of the pot which we used a little while ago, the clay was its material cause; the formal cause is the idea of the statue, or of the pot, or of the octave in music, which the artist has in mind; the artist himself is the efficient cause; and the object of the action, the completed pot, statue, or whatever it may be, is the final cause.[215] That is to say the statue exists potentially in the bronze, the pot potentially in the clay, the octave potentially in the musical sounds, but these things can be called in actual existence only by the operation of the other three causes; and the same thing holds true in animate nature. It is possible therefore to state the matter generally and to say that in every case the individual is produced by the operation of the formal, efficient, and final causes on the material cause, bringing to actuality the potentiality in matter. Of course we may regard the formal, efficient, and final causes as different aspects of the same formal cause—a thing which Aristotle himself does in more than one passage,[216] so that in the last analysis he regards matter and form as the two causes or principles of things. These two are to him correlatives, each completing the other, although he gives greater importance to the formal than to the material cause. These two causes, he says, attract each other; and their union brings about movement, which is always the evolution of something from something else.

From these considerations I trust that it is evident that Aristotle regarded every object of nature, whether animate or inanimate, as the product of causation; behind each individual he found another individual, and he saw that each object was the result of conscious causal activity. So, looking on the world with scientific eyes, he found therein continuous movement dependent on a chain of causes, and he pointed out that such a chain requires a first cause which must be the source of all activity. This first cause was to him Mind, pure Thought, God, conscious, eternal, and good. But his First Cause was at the same time the Final Cause, for the supreme Mind conceives the end toward which all creative activity is tending, that is, it acts with intelligence so that the world is the creation of intelligence and is directed toward wise ends.[217] The order of the universe bears witness to the Mind which set it in order, and which keeps it in motion, all for intelligent ends; for to use Aristotle’s own expression, “God and Nature do nothing without a purpose.”[218] Thus Aristotle introduced into theology cosmological and teleological arguments for the existence of God.

But when Aristotle defines God as pure Thought, the supreme Idea or Form, with no admixture of matter, it might seem that he had contradicted himself. It will be remembered, however, that in his system matter and form do not stand quite on an equality—matter is somewhat subordinate to form. He regarded matter as the point of departure for something higher—the clay being antecedent and lower than the pot, the bronze than the statue—for the higher product always results from the operation of the formal cause on the material. Of course in our illustrations the bronze and the clay are not absolute matter, but only matter with reference to the higher products evolved from them—the pot and the statue. Indeed Aristotle did not suppose that there was such a thing as absolute matter existing by itself, but he rather thought of his material cause as matter not yet formed, the germ from which the actual object was to be developed by the operation of the formal cause. Now he saw in the universe an ascending scale of existence, just as today we recognize such a scale in the animal world, each stage being more perfect than that below it; he pointed out that with reference to the lower, each higher stage was ideal, but material with reference to that which was still higher. So in every stage the idea, the form, preceded and conditioned the material element, and in a sense we may correctly say that Aristotle gradually refined away his material element in the ascending scale. At the summit Aristotle placed the perfect and supreme Idea, God, the eternal antecedent of all activity, the prime mover of the universe. So in the end he identified God and Form. Strictly speaking in his system God could not be a resultant of form and matter, for then God would not be the ultimate being, but some cause would lie behind him; and he would not be perfection, since some potentiality, the characteristic of matter, would still reside in him. As a matter of fact Aristotle in a number of passages identifies his ultimate material and form (ἡ ἐσχάτη ὔλη καὶ ἡ μορφὴ ταὐτό);[219] not that he would have granted that there was a material element in the Supreme Being; but in the light of what we have just said we can understand how he might have held that the ultimate material and God were identical.[220]

It readily follows from Aristotle’s concept of God as the prime mover, the source of all activity in the world, that God can be but one. Monotheism is the logical result of the Aristotelian reasoning. Moreover it was inevitable that Aristotle should make God transcendent, that is, that he should place him above all objects of the natural world, since if the First Cause is pure thought unmixed with matter, he cannot be immanent in material things. The immateriality which Plato gave to his ideas, his pupil transferred to God.

Midway between the natural and the supernatural worlds Aristotle placed man, whom he regarded as bound to the world of nature by his body and the lower elements of his mind, but connected with God through his reason, for he held that the human mind possessed attributes of the divine intelligence. Aristotle’s psychology was based on his belief that there was a purpose in all nature, and on his view that in the individual were always united form and material. With reference to animate beings he showed that they had their formative principle within them, which brought to actuality the material which had the potentiality of life, and which determined the purpose for which the individual creature existed. This formative principle was then for him the soul of the animate being, whether plant, lower animal, or man; it was the internal principle which determined the processes of nutrition, growth, and decay common to all animate creatures, and no less the functions peculiar to the lower and the higher animals throughout the scale of life. The soul of a plant, then, he defined as the assimilative principle (τὸ θρεπτικόν) But creatures of the next, higher stage, the so-called lower animals, he saw had senses, desires, and self-movement; to their souls therefore he assigned the additional elements of sensation (τὸ αἰσθητικόν), appetite (tὸ ὀrektikόn), and motion (τὸ κινητικόν). Finally, he said, the human soul had mind (νοῦς) in addition to the elements possessed by the lower animals and plants, for man has the power of thought and reflection. Therefore man is the highest creature, the most perfect organism in the natural order.

But the human mind, as Aristotle pointed out, has two activities: it concerns itself with knowing and with reasoning; it is passive, receptive, in that it receives ideas from without, and creative in that it can reflect on its own ideas and so create new ideas which are in no sense dependent on material objects—are, as we say, abstract ideas. To this creative part of man’s soul, to his reason alone, did Aristotle grant eternal existence and immortality. All other activities of the soul—knowing, moving, seeking, feeling, and assimilating—he held to be bound to the body and hence to perish with it; but the reasoning element he maintained was in no way dependent on the material world, was always active, and therefore it alone was immortal and eternal.[221] Yet after establishing the immortality of the reasoning element Aristotle failed to define the fate of the immortal human reason after death; of joys or pains beyond the grave he gave no description.

In ethics Aristotle taught that the highest human good was that happiness which results when man’s mind under the direction of reason is active toward virtuous ends; that moral virtue is a habit which is acquired by cultivation, a condition which is attained when the appetites are controlled by the will and guided by the reason. Now in the Aristotelian system man alone was regarded as capable of moral action. The animals are guided by appetite and lack intelligence to direct them; God is pure reason and therefore we cannot attribute to him any moral qualities; but man possesses the characteristics of the lower creatures and has at the same time the divine element, the reason, which connects him with God. Therefore since man is endowed with reason which can either prompt the will to check the appetite or bid the will let appetite go its way, he is capable of choice and so of morality. By thus emphasizing the controlling function of the will Aristotle prepared the way for the Stoics, as we shall see in our next lecture. Virtue in the active life of society was to him always the mean between two extremes, both of which were themselves vices. Courage, for example, lies midway between cowardice and rashness; temperance between indulgence and abstinence; and so on through the whole range of the ethical virtues. Above these virtues of the active life, Aristotle placed a higher rank—the intellectual virtues of wisdom, knowledge, good-sense, practical insight, etc., which result from a harmony of the active and the receptive parts of the intellect. Highest of all he put the speculative activities of the intellect, which he regarded as its proper and most constant function. This “theoretical” or “contemplative” life (θεωρητικὸς βίος) he said brought man his highest happiness just because it was his highest activity. Yet Aristotle could not hold out the hope that men could attain this joy fully or in great numbers; he saw that the greater part of human life was concerned with practical virtues, with good character; and he believed that only when man was good in everyday life could he hope to rise to the contemplative life, but that in that life, at moments, he might catch glimpses of the happiness which belonged continuously to God.[222]

Unquestionably Aristotle did a large service in putting ethics on a more scientific basis than his predecessors had done, but his chief contributions to the subject with which we are now concerned were in the field of theology. There, as we have already noted, he established the cosmological and teleological arguments for the existence of God; and he also introduced a clearly defined transcendentalism, thus making explicit what had been implied in parts of Plato’s teachings. Yet he failed to provide that satisfaction for religious hopes and fears which men desired, and so, as I have said, the cold scientific reasoning of the Stagirite had far less influence in religion than the enthusiastic thought of his teacher until after many centuries had passed.

Although we may readily recognize that the influence of philosophy on the religious belief of the most enlightened in this time was great, we may still question whether it had any considerable influence on the religious customs of the people. Practice is always more conservative than thought, and we find that the thinkers who did most to destroy traditional theology frequently conformed to the traditional worship of the common man. So Socrates sacrificed in the usual way to the gods, although he held advanced ideas with regard to prayers and oaths. No doubt Plato and Aristotle passed for pious so far as their religious practices were concerned, in spite of the fact that they put new content into ancient forms. The former frequently made the speakers in his dialogues refer to the gods in quite the traditional way, and in his Timaeus he set forth a kind of systematic theology; in his Laws, written in his old age as a supplement to his Republic, he planned for his ideal state a religious organization, involving a plurality of gods, not dissimilar to that of the actual Athenian state; he represented his chief spokesman as proving the existence of the gods, giving warrant for the familiar practices of religion, and justifying the ways of gods to men; moreover he proposed to have statutes against impiety and the introduction of religious rites not recognized by law.[223] Aristotle clearly had slight respect for the common notions as to the gods, but for all that he regarded the worship of many gods as natural, and he thought that worship was indispensable for the existence of a state; therefore in his Politics he made a place for a polytheistic religion, defined the duties of priests and other sacred officials, and provided that all the expenses of public worship should be borne by the state.[224] The charge, prompted by political passion, brought against Aristotle for impiety in deifying Hermias, the prince of Mysia, shows that he was not regarded as atheistic.

As a matter of fact with all the changes in religious thought which the centuries brought in Greece, sacred customs and practices remained but little altered down to the end of antiquity. Theology has small interest for the common man. He must depend for his assurance on the performance of those acts which immemorial custom has sanctioned as the proper means of securing the favor of the gods, rather than on the speculations of some theologian or on his own poor reflections. Sacrifice and prayer before the sacred statue or symbol, community worship at the great festivals, private devotion at the shrine within the home, rites of riddance and appeasing, the promise and payment of vows, remained the practices of the mass of men for many centuries after the prophet of Nazareth delivered his message—indeed Christianity took over many of these things and has kept them to the present day. Then too we must remember that the civic character of the common Greek religion had a higher side, for it strengthened the bond of family and of city-state; and through the great festivals at Olympia, Delphi, and Nemea it helped to form a dim concept of a Greek nation. Thus it elevated men’s notions of responsibility to the social units, both small and great. Furthermore, apart from the civic and national sides of Greek religion, the general religious thought of the mass was gradually ennobled with the passage of the centuries; in spite of the survival into later antiquity of certain rude and primitive elements, religion became more moral and more spiritual, as we have already seen was the case with the Eleusinian Mysteries. Plato and Aristotle in the very nature of the case could have little influence on the many in their day; but when their thoughts had been transmuted into terms which the common man could comprehend and express in living, philosophy became for the many a guide of life.