JMC : Pre-Scholastic Philosophy / by Albert Stöckl

Plato's Doctrine of Ideas and Theory of Knowledge.

§ 29.

1. It is, as we have seen, the function of Dialectic to form general (or universal) Notions, and to reduce them, when formed, to organic arrangement, in accordance with their mutual relations. The objects reponding to these general notions are Ideas. By immediate apprehension we have knowledge of the individual object; by the concept we have .knowledge of the Idea. The question naturally presents itself, -- how are we to conceive of these Ideas in their objective state, and what relations are we to conceive them as holding to individual objects, and to God? Plato's manner of answering these questions determines the funaamental character of his whole philosophy.

2. To the first question: low we are to conceive of the Ideas in their objective existence? Plato replies:

(a) The objective correlatives of the Universal Concepts given in our thought, are Universal Ideas. The Universal, as such, is not therefore a mere product of dialectical thought; as Universal, it is objectively real. To the Universal in thought corresponds an Universal in objective reality, and this objective Universal is the Idea. In this wise Plato gives objective existence to the Idea not only as regards the things it represents, but also as regards the form of universality which belongs to our thought of these things -- to our concept.

(b) This being so, Universal Ideas are not something indwelling in individual objects, i.e., an Idea is not the essentia which enters into the being of the several individuals of the same species; since it is Universal, it must be held to transcend all merely individual objects. Universal Ideas, as such, have therefore an independent existence apart from the world of phenomena; the true essences of things represented in these Ideas have being above and apart from things as they exist individually. In a word, we must admit a world of Ideas, distinguished from and transcending the world of phenomena.{1}

(c) The mutual relations subsisting between these transcendental Universal Ideas are the same as the relations subsisting between the corresponding general notions in our thought. As general notions form, in thought, a logical unity, so do the Ideas corresponding to them enter into union in the objective order. But this union is not like the One Being of Parmenides, a lifeless, motionless thing; it involves a dialectical movement towards plurality. As in the process of our thought our concepts are differentiated, and thereby pass from the universal to the particular, so in the objective order of Ideas there is a differentiation of the Universal and the One into the Many. To every Idea belongs "identity with another thing" (ruOrlv), i.e., it is a member in one Unity of Ideal Being; to every Idea belongs also "difference from other things" (Thateron), it carries within it a determinate character which distinguishes it from other Ideas, and by which it becomes other than these. The world of Ideas must therefore be regarded as unity in plurality, and plurality in unity. To admit unity without plurality would be to involve ourselves inextricably in contradiction; to admit plurality without unity would lead to a like result. Reason requires that we should assume both. (Parmenides, p. 137, s. 99; Sophist., p. 254, s. 99).

3. Turning now to the second question: How Plato understands the individual objects of the phenomenal world to be related to the Ideas, we find his teaching to be as follows:

(a) Ideas alone have real being; they alone are perfect, unchangeable, enduring, eternal, imperishable. Unchanging in itself, the ideal world moves in viewless majesty above the world of phenomena, representing within itself the full perfection of Being. The phenomenal world, on the other hand, is the sphere of imperfection, of change, of transition, the region where things exist in time, and begin to be. The existence of material things is a perpetual flux, there is nothing fixed or permanent in them; they are always passing out of existence. In the material world all things oscillate between Being and Non-being. Nothing ever attains perfection, for at each moment things cease to be what they were a moment before. All things are at the transition point from Being to Non-being, and from Non-being to Being; they are, and are not, at the same time. It follows that there can be no question here of Being in its perfection.{2}

(b) Ideas, and the objects of the phenomenal world, are here set in contrast; they have, however, contact with one another (koinônia). The individual objects of the phenomenal order have part in the Ideas (metechousi), each individual object has part in the Idea corresponding to it, and this participation makes it to be what it is (Phaed., p. 101). The Idea is as the real essence of the object; it follows that the object becomes the thing it is only by participating in the Idea corresponding to it. Thus it is that participation in these Ideas determines the proper being of individual objects, as well as the characteristics which distinguish them from one another. In this way things are good in the visible world by participation in the self-subsistent Good, beautiful by participation in sell-subsistent Beauty, wise, holy, just, by participation in sell-subsistent Wisdom, Holiness, Justice. (Phaed. 100, 6. sqq.; Meno. p. 73, &c.)

(c) But in what consists this participation (metechein)? According to Plato it consists in "imitation" homoiôsis) by the phenomenal objects of the corresponding Ideas. The Ideas are the models,

the prototypes (paradeigmata); phenomenal objects are the copies, ectypes (eidôla homoiômata) of these models. Tlie Ideas reflect themselves in the objects as in so many mirrors, and by this reflection of themselves manifest their existence. But this reflection of the Ideas is all the while very imperfect. Sensible objects reproduce but imperfectly the models they represent. Ideas are reflected in them as in a

dimmed mirror. For, in the first place, Matter is not in itself capable reflecting the Idea in its fulness; and in the second place, the process of continual change which involves all things of the phenomenal world in a constant movement of generation and decay, disturbs the clearness of the representation. Tliere is, therefore, no comparison possible between the lustre and grandeur of the Idea in itself, and the copy of it which appears in the world of phenomena. In the supersensible world all is pure and unclouded; in the sensible world, all is dimness and confusion. In the one we have completeness and perfection, in the other incompleteness and imperfection. Plienomenal objects hold, therefore, an intermediate position between Being and Non-being. They are inasmuch as they participate in real Being; they are not inasmuch as they participate in it imperfectly. They do not, however, stand without the realm of Being, for Being is present to them (parousia) as their true essence, even though it be not indwelling (immanent) in them.

4. To our third question: Wliat are the relations of these Ideas to God, Plato's writings furnish this answer: (a) The Idea of God seems in the mind of Plato -- as far at least as his doctrine rests on mere Dialectic -- to have been one with the Idea of the Good. To the Idea of the Good, as to every other Idea, he attributes real being, but he does not identify it with the other Ideas. It is not a logico-metaphysical unit including all Ideas; no trace of such a conception is to be found in the teachings of Plato. On the contrary, he assigns to the Idea of the Good a transcendental position above all other Ideas. The oneness of an Idea Plato describes as ousia, meaning thereby that the Idea is the true essence (ousia) of the objects of sense; but he states expressly that the Idea of the Good is not the ousia itself, but is of a higher order. (De Rep. VI. p. 508, VII. p. 5l7). He makes the Idea of the Good the sun of his world of Ideas. As the sun in this visible world not only renders things visible, but furthermore causes their generation, growth, and continued existence, without however being generated itself, so the Idea of the Good not 'only makes knowable all things that are known, but gives them also Being and Essence, not however becoming itself this Being or Essence, but surpassing them immeasurably in dignity and power. (De Rep. VI. 506-510, VII. p. 517, p. 540, p. 532.)

(b) Respecting the relations established by Plato between the Ideas of mundane things and the Idea of the Good, i.e., the Idea of God, two distinct views have prevailed. Aristotle asserts that Plato established a difference between the Ideas of things and the things themselves, and then attributed to the Ideas, thus isolated, independent existence; and on the strength of this interpretation he sets himself to combat this theory of separation (chôrizein). According to this interpretation, Plato not only assigns to Ideas an existence transcending all individual objects, but he gives them furthermore subsistence apart from the being of God. The later scholastic philosophers have, as a rule, adopted this interpretation. On the other hand, hardly any of the earlier Christian exponents of Plato's philosophy, hardly any of the Fathers of the Church, ascribe to Plato this doctrine of an order of Ideas subsisting apart from the Divine Mind. They assert, almost unanimously, that Plato located his world of Ideas wholly in the Divine Intellect, and regarded the so-called kosmos noêtos as a system of Divine Conceptions.

(c) For ourselves, we will not venture to take sides in the controversy. It seems to us highly probable that Plato regarded the Divine Intellect as the source, and if we may so say, the habitat of Ideas. For he employs, to describe the oneness of the Ideas, the terms nous, sophia, logos, and this he regards not as a lifeless thing, but as a living and moving being. (Phileb. p. 30, Be Rep. VII., p. 517, Soph. p. 248). Moreover, he states expressly regarding the nous that it can exist only in a soul, i.e., in a spiritual being. Again Plato distinctly asserts that God is the First Author, the phutourgos of all Ideas (De Rep. X., p. 597), and teaches that the nous and alêtheia are brought forth by that cause which is the cause of all things (Phileb. p. 30). These assertions seem to warrant the view that Plato did not attribute to Ideas independent subsistence apart from God, but rather regarded them as conceptions of the Divine Intellect. However, the authority of Aristotle in the matter cannot be lightly set aside, as is sometimes done; for he was the immediate disciple of Plato. It is not to be assumed that a man of Aristotle's wonderful acuteness of intellect failed to understand his master, and there does not seem to be any reason to believe that he wilfully misrepresented his teaching. It has indeed been asserted that Aristotle, not admitting Ideas into his own system, deliberately misrepresented

Plato's theory of Ideas in order the more easily to refute it. But this an accusation for which no positive proofs can be adduced. We therefore hold as more probable the opinion that Plato regarded Ideas as conceptions of the Divine Mind; but, for the reasons assigned, we refrain from stating this opinion as absolutely certain.{3}

5. Plato's Theory of Knowledge is intimately connected with his doctrine of Ideas. Considering knowledge in its subjective aspect, we find that Plato distinguishes various kinds of knowledge according to the various objects. The prominent difference established in this connection is the difference between sensible and supersensible objects (horaton kai noêton genos). Sensible objects are of two kinds -- real bodies and the semblances of these bodies, such as are produced by art (sômata and eikones). Supersensible objects are also of two kinds; they are either mathematical entities or Ideas proper (mathêmatika and ideai).

6. Accordingly, we must first of all distinguish in human cognition between doxa and noêsis. The doxa is concerned with sensible objects; the noêsis with supersensible. Our sensuous perception must be described as doxa, because sensuous perception can do no more than enable us to form an opinion; it does not issue in complete certainty. Opinion is not indeed absolute uncertainty, but neither is it complete certainty; it is something intermediate between both, partaking of the character of each, just as the sensible order with which it has to do is intermediate between Being and Non-being, and has something of the nature of each. On the other hand, noêsis, which is concerned with the supersensible, attains to absolute certainty -of cognition; the mind in this stage passes out of the vacillating state of mere opinion, and reaches the light of true gnôsis; noêsis. is therefore the form of cognitive action which leads to scientific knowledge -- epistêmê. There is, therefore, an -essential difference between the two kinds of knowledge, the sensuous -and the intellectual, a difference due as well to the essential difference between the objects of cognition as to the nature of the cognitive act itself.

7. We must make a further distinction still in the case both of doxa and noêsis. As has already been observed, doxa may be concerned either with bodies or with the semblances of bodies. In the first case it becomes pistis; in the latter it is mere ekasia To pistis a real something corresponds objectively; to ekasia only a picture of fancy -the one is Perception, the other Imagination. On the other hand, noêsis deals either with mathematical entities or with Ideas; in the former case it becomes dianoia (ratio) ; in the latter, nous (intellectus).

8. In accordance with these notions, Plato sketches (Do Rep. VII. p. 534) the following scheme of human cognition


Noêton genos. Horaton genos.

Mathematika. Somata.


Noêsis. Doxa.

Nous. I Dianoia. Pistis.

9. These distinctions having been established with regard to human cognition viewed from its subjective side, Plato's Theory of Knowledge is further developed as follows

(a.) From our sensuous experience we cannot derive a knowledge of the supersensible. As long as our knowledge has to do with the phenomena manifested through the senses, so long are we like to men in a dream; like men inebriated or insane, we drift upon the current of mere phenomena, without light from any ray of higher knowledge. If we wish to rise to knowledge of true Being -- of Ideas -- we must withdraw from the sphere of mere sense; we must retire within ourselves, and there, with the pure, untroubled gaze of reason, contemplate the Ideal and the Divine. Sensible objects can help us to knowledge of the Ideal only in so far as the blurred reflection of the Ideas which manifest themselves in the world of sense move us to turn from these things and fix our gaze upon the objects of which they are the reflection. And this being so, sensible objects not being for us a means of reaching the Supersensible and the Ideal, the question at once arises, How is the chasm bridged over which separates us from the world of Ideas? In other words, How is contact of the human mind with Ideas -- which, as such, are wholly transcendental entities -- possible and conceivable?

(b.) To this question Plato cannot obtain from mere science an adequate answer. He is, therefore, obliged to recur to an hypothesis. This hypothesis he offers us in his doctrine of the antecedent existence of the soul. The soul, he teaches, has lived an extra-corporeal, purely spiritual life before its union with the body, and lived this life in the sphere of the ideal, not of the phenomenal world. In this state, Ideas were the immediate objects of its contemplation, and in this contemplation it found its happiness. But in consequence of its union with the body (how it came to be united to a body will be explained further on), it has forgotten the objects presented to its contemplation in that extra-corporeal existence. Yet it has not lost the faculty of recalling them to memory. It is stimulated to remembrance of them when it is confronted by the dim and confused pictures of Ideas presented by the objects of the sensible world. The picture awakes in it the remembrance of the prototype, and thus revives the knowledge of the Idea which had been forgotten. The acquisition of knowledge by man is thus no more than a process of memory -- a recollection (anamnêsis). "Discere est reminisci." (Phaedo, p. 72. Meno, p. 81. Phaedr., p. 249.)

Plato endeavours to support this hypothesis by certain scientific arguments. He adduces in its favour three principal proofs:

1. When we perceive objects in the world of sense, we form judgments regarding them, we judge them, e.g., to be more or less like, or more or less good, or beautiful, and where there is question of human actions we judge them to be more or less just, holy, and so forth. But this clearly supposes that the notion of Likeness in itself, of Goodness, Beauty, Justice, Holiness, in se, existed antecedently in our minds; for we can judge of the more and less of Likeness, Goodness, Beauty, &c., in things only in so far as we compare them with Likeness, Goodness, Beauty, &c., in themselves, and determine whether they approach to or recede from the latter. Now man forms judgments of this kind at the moment that he first begins to use his reason; these notions must, therefore, have existed in his mind antecedently to all experience. It follows necessarily that the soul must have made acquaintance with the Ideas in question before its union with the body, that it has brought these notions with it into its present condition, and that the renewed knowledge of them in its present life is no more than mere remembrance. (Phaedo, p. 74.)

2. The same conclusion is suggested by the Heuristic Method of instruction. In this method the learner is led by a series of questions, arranged in logical sequence, to the knowledge of a given truth. In this process the truth is not given him from without; he is led to find it in himself. The questioning is merely an aid to a discovery which he makes in his own mind, it is merely a condition of the re-awakening of knowledge in the mind of the learner. This being so, it follows that the truths which the mind thus draws out of itself must have been present within it antecedently to all teaching and to all experience, that the mind must have acquired them before its present life began, that it must, consequently, have brought them with it into this terrestrial existence, and that the renewed knowledge of them is no more than a recollection of what, at some previous time, was the object of the mind's contemplation. (Phaedo, p. 73, Men. p. 82.)

10. Thus much with regard to Plato's doctrine of Ideas and Theory of Knowledge. We pass now to his Physics, in which are included his Theology, his Cosmogony, and his Psychology.

<< ======= >>

{1} Plato discovers a proof of this (Tim. p. 51) in the difference between scientific knowledge and mere right opinion (nous and doxa alethes). "If they are," he says, "two different kinds of knowledge, there must exist an order of Ideas having distinct existence, of which we have knowledge not by sense-perception, but by thought (eidê n oumena) ; on the other hand, if they are one and the same, as some have thought, ideas cease to have objective existence, and become mere subjective concepts. In point of fact, however, they are two different kinds of knowledge, and the difference is one of origin (the one being induced by conviction, the other by persuasion), as well as of nature (the one being certain and immutable, the other untrustworthy and changeable.) It follows that there are two classes of objects the one class including all that is unchangeable, that does not come into being, and does not cease to be, that does not receive anything of alien nature into its being, nor pass itself into anything else, i.e., all Transcendental Universal Ideas ; the other class includes those individual objects which bear the same name and belong to the same species as the Ideas, which exist in a determinate place, which come into existence and cease to be, and are unceasingly in motion."

{2} We may observe that Plato here endeavours to combine the principles set in contrast by the pre-Socratic philosophy -- the principle of continual change or unceasing flux held by the Ionians, and the principle of unchanging Being held by the Eleatics. He adopts at once a sphere of immutable being, and another of continuous change, but makes the one distinct from the other, in order to preserve to each its characteristic attributes. Aristotle (Met. I., 6 and XIII. 4. 9.) describes Plato's doctrine of Ideas as the common product of Heraclitus' theory of constant flux, and the Socratic tendency to fixed concepts. The view that the world of sense is subject to ceaseless change was borrowed by Plato from Cratylus, a disciple of Heraclitus, and was thenceforth maintained by him. Accordingly, when Socrates made him acquainted with these concepts of things which, once formed, can be held without change, he was precluded from referring these to sensible objects, and was thus forced to assume the existence of things of another order -- special objects of conceptual knowledge -- and those he named Ideas."

{3} In his old age Plato is said to have occupied himself in resolving Ideas into Ideal numbers. Aristotle is our authority for this. "In point of fact we find certain traces of notions of this kind in some of the dialogues, as for example in the Philebus, where Ideas are described as henades or monades, and (in Pythagorean fashion) peras and apeiron appear as their elementary constituents. According to Aristotle's account (Met. I. 6. 14, 1) Plato held that there were two elements (stoicheia) of Ideas, as of all other things, a form-giving element (peras) and an element formless in itself, but receptive of a form (apeiron). He appears to have assumed for every class of objects (Ideas, mathematical entities, sensible objects) stoicheia of this kind, and to have considered every object as a third term formed out of the two combined (mikton). In sensible objects the apeiron is matter, as described in Timaeus, and the peras is Form and Quality; whereas in the noeta, the peras is Unity (hen), and the apeiron is the More and the Less, the Great and the Little. From these elements, says Aristotle (Met. I. 6) number arises naturally (euphuôs). We can derive Ideas from them only when we reduce them to numbers. Plato distinguishes between those numbers which constitute Ideas, and Mathematical numbers. To the latter he assigns a place intermediate between Ideas and sensible objects. The one (hen) he identifies with the Idea of the Good." Cf. Ueberweg.