Plato

The Platonic Doctrine of Forms or Ideas

Plato’s theory of the "Forms" or "Ideas" represents his most significant philosophic contribution. However obscure and unsatisfactory that his theory may be to us, it gathers around itself the novel insights that lead Plato’s philosophy beyond anything that had been thought before him. Basically, the "Forms" or "Ideas" are those changeless, eternal and non-material essences or patterns of which the actual visible objects we see are only poor copies. There is the Form of the Triangle and all the triangles we see are mere copies of that Form. This tentative description of the Forms as non-material realities already indicates what was so novel about this Platonic doctrine. Whereas the Presocratic philosophers thought of reality as material stuff of some sort, Plato now designated the non-material Ideas or Forms as the true reality. Similarly whereas the Sophists thought that all knowledge is relative because the material order, which is all they knew, is constantly sifting and changing, Plato argued that knowledge is absolute because the true object of thought is not the material order but the changeless and eternal order of the Ideas or Forms. Although Socrates anticipated this view by holding that there is an absolute Good, which makes possible our judgments of particular goods, Plato went beyond Socrates’ ethical concern by adding to the concept of Good a theory of metaphysics, an explanation of the whole structure of reality and the place of morality in it. Moreover, Plato had fashioned with this theory of Forms a novel explanation of the relation between the One and the Many, avoiding Parmenides’ conclusion that everything is One and Heraclitus’ conclusion that everything is in flux. He was aided by the Pythagorean concept of form as it derived from mathematics. In the end, however, Plato’s doctrine of Ideas was something new and became the central concept in all his philosophy. 

The doctrine of Forms represents a serious attempt to explain the nature of existence. We had certain kinds of experiences that raise the question about existence for us. For example, we make judgments about things and behavior, saying about a thing that it is beautiful and about an act that it is good. This suggests that there is somewhere a standard of beauty, which is different from the thing we are judging, and that there is a standard of good, which is somehow separate from the person or his act that we judge. Moreover, visible things change – they come and go, generate and perish. Their existence is brief. Compared to things, Ideas such Good and Beautiful seem timeless. They have more "being" than things. Plato concluded, therefore, that the real world is not the visible world but rather the intelligible world. The intelligible world is most real said Plato because it consists of the eternal Forms. There are at least five questions that one might want to ask about the Forms. Although they cannot be answered with precision, the replies to them that are found in his various writings will provide us with Plato’s general theory of the Forms.  

What are the Forms?

We have already suggested Plato’s answer to this question by saying that the Forms are eternal patterns of which the objects that we see are only copies. A beautiful person is a copy of Beauty. We can say about a person that she is beautiful because we know the Idea of Beauty and recognize that person shares more or less in this Idea. In his Symposium, Plato suggests that we normally apprehend beauty first of all in a particular object or person but having discovered beauty in this limited form, we soon "perceive that the beauty of one form is akin to another," and so we move from the beauty of a particular body to the recognition that beauty "in every form in one and the same." The effect of this discovery that all modes of beauty have some similarity is to loosen one’s attachment to the beautiful object and to move from the beautiful physical object to the concept of Beauty. When a person discovers this general quality of Beauty, says Plato, "he will abate his violent love of the one which he will … deem a small thing and will become a lover of all beautiful forms; in the next stage he will consider that the beauty of the mind is more honorable than the beauty of outward form." Then, "drawing towards and contemplating the vast sea of beauty, he will create many fair and noble thoughts and notions and boundless love of wisdom; until on that shore he grows and waxes strong, and at last the vision is revealed to him of a single science, which is the science of beauty everywhere." Plato appears to be saying that beautiful things in their multiplicity point toward a Beauty from which everything else derives its beauty. But this Beauty is not merely a concept: Beauty has objective reality. Beauty is a Form or Idea. Things become beautiful: but Beauty always is. Accordingly, Beauty has a separate existence from those changing things which move in and out of Beauty.  

In the Republic, Plato shows that the true philosopher is concerned to know the essential nature of things. When we ask what is justice or beauty, he does not want examples of just and beautiful things. He wants to know what makes these things just and beautiful. The difference between opinion and knowledge is just this, that those who are at the level of opinion can recognize a just act but cannot tell you why it is just. They do not know the essence of Justice, which the particular act shares. Knowledge is now concerned simply with passing facts and appearances, with the realm of becoming. Knowledge seeks what truly is; its concern is with Being. What really is, what has Being, is the essential nature of things; these essences, such as Beauty and Goodness, which make it possible for us to judge things as good or beautiful, these are eternal Forms or Ideas.  

It would seem that besides the Forms of Beauty and Goodness, there would be many other Forms. Plato speaks of the Ideal Bed of which the beds we see are mere copies. But this raises the question whether there are as many Forms as there are essences or essential natures. Although Plato is not sure that there are Ideas or Forms of dog, water, and other things, he indicates in the Parmenides that there are "certainly not" Ideas of mud and dirt. Clearly, if there were Forms behind all classification of things, there would have to be a duplicate world. These difficulties increase as one tries to specify how many and which Forms there are. Nevertheless, what Plato means by the Forms is clear enough, for he considers them to be the essential archetypes of things, having an eternal existence, apprehended by the mind and not the senses, for it is the mind that beholds "real existence, colorless, formless and intangible, visible only to the intelligence." 

Where Do the Forms Exist?

If the Forms are truly real, if they embody Being, it would seem that they must be someplace. But how can the Forms, which are immaterial, have location? It could hardly be said that they are spatially located. Plato’s clearest suggestion on this problem is that the Forms are "separate" from concrete things, they exist "apart from" the things we see. To be "separate" or "apart from" must mean simply that the Forms have an independent existence; they persist even though particular things perish. Forms have no dimension, but the question of their location comes up as a consequence of our language, which implies that Forms, being something, must be someplace in space. It may be that nothing more can be said about their location than the fact that the Forms have an independent existence. But there are two additional ways in which this is emphasized by Plato. For one thing, in connection with his theory of the preexistence of the soul, he says that the human soul was acquainted with the Forms before it was united with the body. Secondly, in the process of creation, the Demiurge or god used the Forms in fashioning particular things, suggesting that the Forms had an existence prior to their embodiment in things. Furthermore, these Forms seem to have originally existed in the "mind of God" or in the supreme principle of rationality, the One. Aristotle says in his Metaphysics that "the Forms are the cause of the essence of all other things, and the one is the cause of the Forms." Just as the sun in the allegory of the Cave was once the source of light and life, so also, said Plato, the Idea of the Good is "the universal author of all things beautiful and right, parent of light and of the lord of light in this world, and the source of truth and reason in the other." Whether the Forms truly exist in the mind of God is a question, but that the Forms are the agency through which the principle of reason operates in the universe seems to be just what Plato means.  

What is the Relation of Forms to Things?

A Form can be related to a thing in three ways, which may be three ways of saying the same thing. First, the Form is the cause of the essence of a thing. Next, a thing may be said to participate in a Form. And, finally, a thing may be said to imitate or copy a Form. In each case, Plato implies that although the Form is separate from the thing, that the Idea of Man is different from Socrates, still, every concrete or actual thing in some way owes its existence to a Form, in some degree participates in the perfect model of the class of which it is a member, and is in some measure an imitation or copy of the Form. Later on, Aristotle was to argue that form and matter are inseparable and that the only real good or beautiful was found in actual things. But Plato would only allow participation and imitation as the explanation of the relation between things and their Forms. He accentuated this view by saying that it was the Forms through which order was brought into the chaos, indicating the separate reality of form and matter. Aristotle’s criticism of Plato’s view seems formidable, since there seems to be no coherent way of accounting for the existence of the Forms apart from actual things. Still, Plato would ask him what makes it possible to form a judgment about the imperfection of something if the mind does not have access to anything more than the imperfect thing.  

What is the Relation of Forms to Each Other?

Plato says that "we can have discourse only through the weaving together of Forms." Thinking and discussion proceed for the most part on a level above particular things. We speak in terms of the essences or universals that things illustrate, so we speak of queens, dogs, and carpenters. These are definitions of things and as such are universals or Forms. To be sure, we also refer to specific things in our experiences, such as dark and beautiful and person, but our language reveals our practice of connecting Forms with Forms. There is the Form Animal and such subclasses of Forms as Man and Horse. Forms are, therefore, related to each other as genus and species. In this way Forms tend to interlock even when retaining their own unity. The Form Animal seems to be present also in the Form Horse, so that one Form partakes of the other. There is therefore a hierarchy of Forms representing the structure of reality, of which the visible world is only a reflection. The "lower" one comes in this hierarchy of Forms, the closer one comes to visible things and therefore the less universal is one’s knowledge, as when one speaks of "red apples." Conversely, the higher one goes, or the more abstract the Form, as when one speaks of Apple in general, the broader one’s knowledge. The discourse of science is the most abstract, but for that very reason, because it has achieved such independence from particular cases and particular things, it possesses the highest form of knowledge. The botanist who has proceeded in knowledge from this rose to Rose and to Flower has achieved the kind of abstraction or independence from particulars of which Plato was here thinking. This does not mean, however, that Plato thought that all Forms could be related to each other; he only meant to say that every significant statement involves the use of some Forms and that knowledge consists of understanding the relations of the appropriate Forms to each other.  

How Do We Know the Forms?

Plato indicates at least three different ways in which the mind discovers the Forms. First, there is recollection: before it was united with the body, the soul was acquainted with the Forms. People now recollect what their souls knew in their prior state of existence. Visible things remind them of the essences previously known. Education is actually a process of reminiscence. Second, people arrive at the knowledge of the Forms through the activity of dialectic, which is the power of abstracting the essence of things and discovering the relations of all divisions of knowledge to each other. And third, there is the power of desire, love (eros), which leads people step by step, as Plato described in the Symposium, from the beautiful object to the beautiful thought and then to the very essence of Beauty itself.  

The doctrine of Forms leaves many questions as well as problems. Plato’s language gives the impression that there are two distinct worlds, but the relationship of these worlds is not easily conceived. Nor is the relation between Forms and their corresponding objects as clear as one would wish. Still, his argument is highly suggestive, particularly as he seeks to account for our ability to make judgments of value. To say a thing is better or worse implies some standard, which obviously is not there as such in the thing being evaluated. The doctrine of the Forms also makes possible scientific knowledge, for clearly the scientist has let go of actual visible particulars and deals with essences or universals, that is, with "laws." The scientist formulates "laws" and these laws tell us something about all things, not only the immediate and particular things. Although this whole doctrine of the Forms rests upon Plato’s metaphysical views, that ultimate reality is non-material, it goes a long way toward explaining the more simple fact of how it is possible for us to have ordinary conversation. Any discourse between human beings, it would seem, illustrates our independence from particular things. Conversation, Plato would say, is the clue that leads us to the Forms, for conversation involves more than seeing. The eye can see only the particular thing, but the thinking that animates conversation departs from specific things as thought "sees" the universal, the Form. There is in the end a stubborn lure in Plato’s theory, even though it ends inconclusively. 

Plato’s View of the Cosmos

Although Plato’s most consistent thought is centered around moral and political philosophy, he also turned his attention to science. His theory of nature, or physics, is found mainly in the Timaeus, a dialogue that he wrote when he was about seventy years old. Plato had not deliberately postponed this subject, nor had he chosen to deal with moral matters instead of promoting the advancement of science. On the contrary the science of his day had reached a blind alley, and there seemed to be no fruitful direction to take in this field. Earlier, according to Plato, Socrates had had "a prodigious desire to know that department of philosophy which is called the investigation of nature; to know the causes of things …" but he was disillusioned by the conflicting answers and theories put forward by Anaximander, Anaximenes, Leucippus and Democritus, and others. Plato shared this same disappointment. Moreover, as his own philosophy took shape, some of his theories about reality cast doubt upon the possibility of a strictly accurate scientific knowledge. Physics, he thought, could never be more than "a likely story." It was particularly his theory of the Forms that rendered science as an exact mode of knowledge impossible. The real world, he said, is the world of Forms, whereas the visible world is full of change and imperfection. Yet, it is about the visible world of things that science seeks to build its theories. How can one formulate accurate, reliable, and permanent knowledge about a subject matter which is itself imperfect and full of change? At the same time, Plato clearly felt that his theory of Forms or Ideas as well as his notions of morality, evil, and truth required that he provide some view of the cosmos in which all these elements of his thought could be brought together in a coherent way. Recognizing, then, that his account of the real world was only "a likely story," or at best probable knowledge, he nevertheless was convinced that what he had to say about the world was as accurate as the subject matter would allow.  

Plato’s first thought about the world is that, though it is full of change and imperfection, it nevertheless exhibits order and purpose. He rejected the explanation given by Democritus, who had argued that all things came into being through the accidental collision of atoms. When Plato considered the orbits of the planets he observed that they were arranged according to a precise series of geometrical intervals, which, when appropriately calculated, produced the basis for the harmonic scale. Plato made much of the Pythagorean use of mathematics in describing the world, though instead of saying, as the Pythagoreans did, that things are numbers, he said that things participate in numbers, that they are capable of a mathematical explanation. This mathematical characteristic of things suggested to Plato that behind things there must be not merely chance and subsequent mechanism but rather thought and purpose. The cosmos must therefore be the work of "intelligence," since it is the mind that orders all things. Humanity and the world bear a likeness to each other, for both contained first an intelligible and eternal element, and second, a sensible and perishing element. This dualism is expressed by the union of soul and body. Similarly, the world is a soul in which things as we know them are arranged. 

Although Plato said that "mind" orders everything, he did not develop a doctrine of creation. The doctrine of creation holds that things are created ex nihilo, out of nothing. But Plato’s explanation of the origin of the visible world bypasses this doctrine of creation. Although Plato does say that "that which becomes must necessarily become through the agency of some cause," this agent, which he calls the divine Craftsman or Demiurge, does not bring new things into being but rather confronts and orders what already exists in chaotic form. We have, then, a picture of the Craftsman with the material upon which he would work. Thus, in explaining the generation of things as we know them in the visible world, Plato assumes the existence of all the ingredients of things, namely, that out of which things are made, the Demiurge who is the Craftsman, and the Ideas or Forms or "patterns" after which things are made.  

Plato departed from the materialists who thought that all things derived from some original kind of matter, whether in the form of earth, air, fire, or water. Plato did not accept the notion that matter was the basic reality; matter itself, said Plato, must be explained in more refined terms as the composition not of some finer forms of matter but of something other than matter. What we call matter, whether in the form of earth or water, is a reflection of an Idea or Form, and these Forms are expressed through a medium. Things are generated out of what Plato calls the "receptacle," which he considered the "nurse of all becoming." The receptacle is a "matrix" or a medium that has no structure but that is capable of receiving the imposition of structure by the Demiurge. Another word Plato uses for the "receptacle" is "space," which he says, "is everlasting, not admitting destruction; providing a situation for all things that come into being, but itself apprehended without the senses by a sort of bastard reasoning, and hardly an object of belief." There is no explanation of the origin of the receptacle, for in Plato’s thought it is underived, as are the Forms and the Demiurge. The receptacle is where things appear and perish.  

To an unreflective person, earth and water may appear as solid and permanent modes of matter. But Plato said that they are constantly changing and that therefore do not hold still long enough "to be described as this or that or by any phrase that exhibits them as having permanent being." What the senses consider "matter" or "substance" when they apprehend the elements of earth and water are only qualities, which appear through the medium of the receptacle, "in which all of them are always coming to be, making their appearance and vanishing out of it." Material objects are composed of non-material compounds. Here Plato is again influenced by the Pythagorean perspective when he argues that solid objects of matter are described and defined in geometrical terms according to their surfaces. Any surface, he said, can be resolved by triangles, and, in turn, any triangle can be divided into right triangles. These shapes, these triangular surfaces, are irreducible and must therefore be the ingredients of the compound known as matter. The simplest solid, for example, would be a pyramid that consists of four triangular surfaces. Similarly, a cube could be made of six square surfaces, where each square surface is composed of two half squares, that is, two triangles. What we normally call "solid" never contains anything more than "surfaces," so that one can say that "body" or "molecules" are geometric figures. Indeed, the whole universe could be thought of in terms of its geometrical diagram – and could be defined simply as what is happening in space or as space reflecting various forms. What Plato wanted particularly to establish was the notion that matter is only the appearance of something more basic. 

If various kinds of triangles represent the basic constituents of all things, how can one account for the variations in things as well as their stability? What, in short, makes it possible to have the kind of world and universe that we know? Here again Plato was forced to assume that all things must be ordered by the mind, and the cosmos is the activity of the World Soul in the receptacle. The world of things is the world of phenomena which is the Greek word for appearances. What is presented to our perceptions is the multitude of appearances, which, when analyzed, are found to consist of geometric surfaces. These surfaces, again, are primary and irreducible and are found as "raw material" in the receptacle and require some organizing agency to arrange them into triangles and then into phenomena. All this activity is achieved by the World Soul. The World Soul is eternal, though at times Plato appears to say that it is the creation of the Demiurge. Although the World Soul is eternal, the world of appearance is full of change, just as in humans the soul represents the eternal element whereas the body contains the principle of change. The world of matter and body changes because it is composite and always tends to return to its basic constituents, "going into" and "going out of" space. But insofar as the World Soul is eternal, there is, in spite of all the change in the world of our experience, an element of stability and permanence, a structure, a discernible universe. Space, in the Timaeus, corresponds to no feature of the intelligible world. Space is simply that out of which the copy is made; it is like the sculptor’s clay. The argument of the Timaeus contains no attempt at a deduction of space. Just as the Ionians started their cosmogony from the assertion of matter as a given fact, or rather the assertion of matter and space as two given facts, insofar as they held matter to be capable of condensation and rarefaction, so the Timaeus begins its cosmogony with space or with matter, for matter and space are not at this stage differentiated. The Timaeus does not eliminate matter, it identifies it with space as the receptacle of forms, and presupposes it. When we say that space is presupposed and not deduced what we mean can be stated in the language of the Timaeus by saying that no attempt is made in the dialogue to show that God "made" space. 

Finally, there is the question about "time." According to Plato, time comes to be only after phenomena are produced. Not until there are things as we know them, as imperfect and changing, can there be time. Until then, by definition, whatever is, is eternal. The very meaning of time is change, and therefore in the absence of change there could be no time. Whereas the Forms are timeless, the various copies of them in the receptacle constantly "go in" and "go out," and this going in and out is the process of change, which is the cause of time. Still, time represents the double presence in the cosmos of time and eternity; since the cosmos is ordered by mind, it contains the element of eternity, and since the cosmos consists of temporary combinations of surfaces, it contains the element of change and time. And since change is not capricious but regular, the very process of change exhibits the presence of eternal mind. This regularity of change, as exhibited, for example, by the regular change or motion of the stars or planets, makes possible the measurement of change and makes it possible to "tell time."  

Plato’s "likely story" about the cosmos consisted, then, of an account of how the Demiurge fashioned things out of the receptacle, using the Forms as patterns. The World Soul is produced by the Demiurge and is the energizing activity in the receptacle, producing what to us appears to be substance or solid matter though in reality is only qualities caused by the arrangement of geometric surfaces. Evil and time are, in this account, the product of imperfection and change. The world as we know it depends upon an agency and "raw material" that are not found in the physical world as we know it, this agency being mind, and the raw material being explained chiefly in terms of mathematics.  

At this point one would wish to engage in a sustained and critical appraisal of Plato’s system of philosophy. But in a sense, the history of philosophy represents just such a large scale dialogue, where thinkers arise to agree and disagree with what he taught. So powerful were his ideas that for centuries to come his views dominated the enterprise of philosophy. Indeed, Whitehead once remarked that "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato." Many of these footnotes were written by Plato’s successor, Aristotle.