Part 8

The Theatætus is followed by the trilogy of the Sophist, the Statesman, and the Philosopher, which completes the Megaric group of dialogues. The first of these dialogues examines the conception of appearance, that is of the not-being, the last (for which the Parmenides may be taken) the conception of being. Both dialogues are especially directed to the Eleatic doctrine. After Plato had recognized the conception in its simple unity as that which abides in the change of phenomena, his attention was naturally turned towards the Eleatics, who in an opposite way had attained the similar result that in unity consists all true substantiality, and to multiplicity as such no true being belongs. In order more easily on the one side to carry out this fundamental thought of the Eleatic to its legitimate result, in which the Megarians had already preceded him, he was obliged to give a metaphysical substance to his abstract conceptions of species, _i. e._ ideas. But on the other side, he could not agree with the inflexibility and exclusiveness of the Eleatic unity, unless he would wholly sacrifice the multiplicity of things; he was rather obliged to attempt to show by a dialectic development of the Eleatic principle that the one must be at the same time a totality, organically connected, and embracing multiplicity in itself. This double relation to the Eleatic principle is carried out by the Sophist and the Parmenides; by the former polemically against the Eleatic doctrine, in that it proves the being of the appearance or the not-being, and by the latter pacifically, in that it analyzes the Eleatic one by its own logical consequences into many. The inner progress of the doctrine of Ideas in the Megaric group of dialogues is therefore this, viz., that the Theatætus, in opposition to the Heraclitico-Protagorean theory of the absolute becoming, affirms the objective and independent reality of ideas, and the Sophist shows their reciprocal relation and combining qualities, while the Parmenides in fine exhibits their whole dialectic completeness with their relation to the phenomenal world.

THE THIRD PERIOD begins with the return of the philosopher to his native city. It unites the completeness of form belonging to the first with the profounder characteristical content belonging to the second. The memories of his youthful years seem at this time to have risen anew before the soul of Plato, and to have imparted again to his literary

## activity the long lost freshness and fulness of that period, while at

the same time his abode in foreign lands, and especially his acquaintance with the Pythagorean philosophy, had greatly enriched his mind with a store of images and ideals. This reviving of old memories is seen in the fact that the writings of this group return with fondness to the personality of Socrates, and represent in a certain degree the whole philosophy of Plato as the exaltation of the doctrine and the ideal embodiment of the historical character of his early master. In opposition to both of the first two periods, the third is marked externally by an excess of the mythical form connected with the growing influence of Pythagoreanism in this period, and internally by the application of the doctrine of ideas to the concrete spheres of psychology, ethics and natural science. That ideas possess objective reality, and are the foundation of all essentiality and truth, while the phenomena of the sensible world are only copies of these, was a theory whose vindication was no longer attempted, but which was presupposed as already proved, and as forming a dialectical basis for the pursuit of the different branches of science. With this was connected a tendency to unite the hitherto separate branches of science into a systematic whole, as well as to mould together the previous philosophical directions, and show the inner application of the Socratic philosophy for ethics, of the Eleatic for dialectics, and the Pythagorean for physics.

Upon this standpoint, the Phædrus, Plato’s inaugural to his labors in the Academy, together with the Symposium, which is closely connected with it, attempts to subject the rhetorical theory and practice of their time to a thorough criticism, in order to show in opposition to this theory and practice, that the fixedness and stability of a true scientific principle could only be attained by grounding every thing on the idea. On the same standpoint the Phædon attempts to prove the immortality of the soul from the doctrine of ideas; the Philebus to bring out the conception of pleasure and of the highest good; the Republic to develop the essence of the state, and the Timæus that of nature.

Having thus sketched the inner development of the Platonic philosophy, we now turn to a systematic statement of its principles.

III.—CLASSIFICATION OF THE PLATONIC SYSTEM.—The philosophy of Plato, as left by himself, is without a systematic statement, and has no comprehensive principle of classification. He has given us only the history of his thinking, the statement of his philosophical development; we are therefore limited in reference to his classification of philosophy to simple intimations. Accordingly, some have divided the Platonic system into theoretical and practical science, and others into a philosophy of the good, the beautiful and the true. Another classification, which has some support in old records, is more correct. Some of the ancients say that Plato was the first to unite in one whole the scattered philosophical elements of the earlier sages, and so to obtain for philosophy the three parts, logic, physics, and ethics. The more accurate statement is given by _Sextus Empiricus_, that Plato has laid the foundation for this threefold division of philosophy, but that it was first expressly recognized and affirmed by his scholars, Xenocrates and Aristotle. The Platonic system may, however, without difficulty, be divided into these three parts. True, there are many dialogues which mingle together in different proportions the logical, the ethical, and the physical element, and though even where Plato treats of some special discipline, the three are suffered constantly to interpenetrate each other, still there are some dialogues in which this fundamental scheme can be clearly recognized. It cannot be mistaken that the Timæus has predominantly a physical, and the Republic as decidedly an ethical element, and if the dialectic is expressly represented in no separate dialogue, yet does the whole Megaric group pursue the common end of bringing out the conception of science and its true object, being, and is, therefore, in its content decidedly dialectical. Plato must have been led to this threefold division by even the earlier development of philosophy, and though Xenocrates does not clearly see it, yet since Aristotle presupposes it as universally admitted, we need not scruple to make it the basis on which to represent the Platonic system.

The order which these different parts should take, Plato himself has not declared. Manifestly, however, dialectics should have the first place as the ground of all philosophy, since Plato uniformly directs that every philosophical investigation should begin with accurately determining the _idea_ (_Phæd._ p. 99. Phædr. p. 237), while he subsequently examines all the concrete spheres of science on the standpoint of the doctrine of ideas. The relative position of the other two parts is not so clear. Since, however, the physics culminates in the ethics, and the ethics, on the other hand, has for its basis physical investigations into the ensouling power in nature, we may assign to physics the former place of the two.

The mathematical sciences Plato has expressly excluded from philosophy. He considers them as helps to philosophical thinking (_Rep._ VII. 526), as necessary steps of knowledge, without which no one can come to philosophy (_Ib._ VI. 510); but mathematics with him is not philosophy, for it assumes its principles or axioms, without at all accounting for them, as though they were manifest to all, a procedure which is not permitted to pure science; it also serves itself for its demonstrations, with illustrative figures, although it does not treat of these, but of that which they represent to the understanding (_Ib._). Plato thus places mathematics midway between a correct opinion and science, clearer than the one, but more obscure than the other. (_Ib._ VII. 533.)

IV. THE PLATONIC DIALECTICS. 1. CONCEPTION OF DIALECTICS.—The conception of dialectics or of logic, is used by the ancients for the most part in a very wide sense, while Plato employs it in repeated instances interchangeably with philosophy, though on the other hand he treats it also as a separate branch of philosophy. He divides it from physics as the science of the eternal and unchangeable from the science of the changeable, which never is, but is only ever becoming; he distinguishes also between it and ethics, so far as the latter treats of the good not absolutely, but in its concrete exhibition in morals and in the state; so that dialectics may be termed philosophy in a higher sense, while physics and ethics follow it as two less exact sciences, or as a not yet perfected philosophy. Plato himself defines dialectics, according to the ordinary signification of the word, as the art of developing knowledge by way of dialogue in questions and answers. (_Rep._ VII. 534). But since the art of communicating correctly in dialogue is according to Plato, at the same time the art of thinking correctly, and as thus thinking and speaking could not be separated by the ancients, but every process of thought was a living dialogue, so Plato would more accurately define dialectics as the science which brings speech to a correct issue, and which combines or separates the species, _i. e._ the conceptions of things correctly with one another. (_Soph._ p. 253. _Phædr._ p. 266). Dialectics with him has two divisions, to know what can and what cannot be connected, and to know how division or combination can be. But as with Plato these conceptions of species or ideas are the only actual and true existence, so have we, in entire conformity with this, a third definition of dialectics (_Philebus_ p. 57), as the science of being, the science of that which is true and unchangeable, the science of all other sciences. We may therefore briefly characterize it as the science of absolute being or of ideas.

2. WHAT IS SCIENCE? (1.) _As opposed to sensation and the sensuous representation._—The Theatætus is devoted to the discussion of this question in opposition to the Protagorean sensualism. That all knowledge consists in perception, and that the two are one and the same thing, was the Protagorean proposition. From this it followed, as Protagoras himself had inferred, that things are, as they appear to me, that the perception or sensation is infallible. But since perception and sensation are infinitely diversified with different individuals, and even greatly vary in the same individual, it follows farther, that there are no objective determinations and predicates, that we can never affirm what a thing is in itself, that all conceptions, great, small, light, heavy, to increase, to diminish, &c., have only a relative significance, and consequently, also, the conceptions of species, as combinations of the changeful many, are wholly wanting in constancy and stability. In opposition to this Protagorean thesis, Plato urges the following objections and contradictions. _First._ The Protagorean doctrine leads to the most startling consequences. If being and appearance, knowledge and perception are one and the same thing, then is the irrational brute, which is capable of perception, as fully entitled to be called the measure of all things, as man, and if the representation is infallible, as the expression of my subjective character at a given time, then need there be no more instruction, no more scientific conclusion, no more strife, and no more refutation. _Second._ The Protagorean doctrine is a logical contradiction; for according to it Protagoras must yield the question to every one who disputes with him, since, as he himself affirms, no one is incorrect, but every one judges only according to truth; the pretended truth of Protagoras is therefore true for no man, not even for himself. _Third._ Protagoras destroys the knowledge of future events. That which I may regard as profitable may not therefore certainly prove itself as such in the result. To determine that which is really profitable implies a calculation of the future, but since the ability of men to form such a calculation is very diverse, it follows from this that not man as such, but only the wise man can be the measure of things. _Fourth._ The theory of Protagoras destroys perception. Perception, according to him, rests upon a distinction of the perceived object and the perceiving subject, and is the common product of the two. But in his view the objects are in such an uninterrupted flow, that they can neither become fixed in seeing nor in hearing. This condition of constant change renders all knowledge from sense, and hence (the identity of the two being assumed), all knowledge impossible. _Fifth._ Protagoras overlooks the apriori element in knowledge. It is seen in an analysis of the sense-perception itself, that all knowledge cannot be traced to the activity of the senses, but that there must also be presupposed besides these, intellectual functions, and hence an independent province of supersensible knowledge. We see with the eyes, and hear with the ears, but to group together the perceptions attained through these different organs, and to hold them fast in the unity of self-consciousness, is beyond the power of the activity of the senses. Again, we compare the different sense-perceptions with one another, a function which cannot belong to the senses, since each sense can only furnish its own distinctive perception. Still farther, we bring forward determinations respecting the perceptions which we manifestly cannot owe to the senses, in that we predicate of these perceptions, being and not-being, likeness and unlikeness, &c. These determinations, to which also belong the beautiful and the odious, good and evil, constitute a peculiar province of knowledge, which the soul, independently of every sense-perception, brings forward through its own independent activity. The ethical element of this Plato exhibits in his attack upon sensualism, and also in other dialogues. He maintains (_in the Sophist_), that men holding such opinions must be improved before they can be instructed, and that when made morally better, they will readily recognize the truth of the soul and its moral and rational capacities, and affirm that these are real things, though objects of neither sight nor of feeling.

(2.) _The Relation of Knowing to Opinion._—Opinion is just as little identical with knowing as is the sense-perception. An incorrect opinion is certainly different from knowing, and a correct one is not the same, for it can be engendered by the art of speech without therefore attaining the validity of true knowledge. The correct opinion, so far as it is true in matter though imperfect in form, stands rather midway between knowing and not-knowing, and participates in both.

(3.) _The Relation of Science to Thinking._—In opposition to the Protagorean sensualism, we have already referred to an energy of the soul independent of the sensuous perception and sensation, competent in itself to examine the universal, and grasp true being in thought. There is, therefore, a double source of knowledge, sensation and rational thinking. Sensation refers to that which is conceived in the constant becoming and perpetual change, to the pure momentary, which is in an incessant transition from the was, through the now, into the shall be (_Parm._ p. 152); it is, therefore, the source of dim, impure, and uncertain knowledge; thinking on the other hand refers to the abiding, which neither becomes nor departs, but remains ever the same. (_Tim._ p. 51.) Existence, says the Timæus (p. 27) is of two kinds, “that which ever is but has no becoming, and that which ever becomes but never is. The one kind, which is always in the same state, is comprehended through reflection by the reason, the other, which becomes and departs, but never properly is, may be apprehended by the sensuous perception without the reason.” True science, therefore, flows alone from that pure and thoroughly internal activity of the soul which is free from all corporeal qualities and every sensuous disturbance. (_Phæd._ p. 65.) In this state the soul looks upon things purely as they are (_Phæd._ p. 66) in their eternal being and their unchangeable condition. Hence the true state of the philosopher is announced in the Phædon (p. 64) to be a willingness to die, a longing to fly from the body, as from a hinderance to true knowledge, and become pure spirit. According to all this, science is the thinking of true being or of ideas; the means to discover and to know these ideas, or the organ for their apprehension is the dialectic, as the art of separating and combining conceptions; the true objects of dialectics are ideas.

3. THE DOCTRINE OF IDEAS IN ITS GENESIS.—The Platonic doctrine of ideas is the common product of the Socratic method of forming conceptions, the Heraclitic doctrine of absolute becoming, and the Eleatic doctrine of absolute being. To the first of these Plato owes the idea of a knowing through conceptions, to the second the recognition of the becoming in the field of the sensuous, to the third the position of a field of absolute reality. Elsewhere (_in the Philebus_) Plato connects the doctrine of ideas with the Pythagorean thought that every thing may be formed from unity and multiplicity, from the limit and the unlimited. The aim of the Theatætus, the Sophist, and the Parmenides is to refute the principles of the Eleatics and Heraclitics: this refutation is effected in the Theatætus by combating directly the principle of an absolute becoming, in the Sophist by combating directly the principle of abstract being, and in the Parmenides by taking up the Eleatic one and showing its true relations. We have already spoken of the Theatætus; we will now look for the development of the doctrine of ideas in the Sophist and Parmenides.

The ostensible end of the former of these dialogues is to show that the Sophist is really but a caricature of the philosopher, but its true end is to fix the reality of the appearance, _i. e._ of the not-being, and to discuss speculatively the relation of being and not-being. The doctrine of the Eleatics ended with the rejection of all sensuous knowledge, declaring that what we receive as the perception of a multiplicity of things or of a becoming is only an appearance. In this the contradiction was clear, the not-being was absolutely denied, and yet its existence was admitted in the notion of men. Plato at once draws attention to this contradiction, showing that a delusive opinion, which gives rise to a false image or representation, is not possible, since the whole theory rests upon the assumption that the false, the not-true, _i. e._ not-being cannot even be thought. This, Plato continues, is the great difficulty in thinking of not-being, that both he who denies and he who affirms its reality is driven to contradict himself. For though it is inexpressible and inconceivable either as one or as many, still, when speaking of it, we must attribute to it both being and multiplicity. If we admit that there is such a thing as a false opinion, we assume in this very fact the notion of not-being, for only that opinion can be said to be false which supposes either the not-being to be, or makes that, which is not, to be. In short, if there actually exists a false notion, so does there actually and truly exist a not-being. After Plato had thus fixed the reality of not-being, he discusses the relation of being and not-being, _i. e._ the relation of conceptions generally in their combinations and differences. If not-being has no less reality than being, and being no more than not-being, if, therefore, _e. g._ the not-great is as truly real as the great, then every conception may be apprehended according to its opposite sides as being and not-being at the same time: it is a being in reference to itself, as something identical with itself, but it is not-being in reference to every one of the numberless other conceptions which can be referred to it, and with which, on account of its difference from them, it can have nothing in common. The conception of the same ταὐτὸν and the different θάτερον represent the general form of an antithesis. These are the universal formulæ of combination for all conceptions. This reciprocal relation of conceptions as at the same time being and not-being, by virtue of which they can be arranged among themselves, forms now the basis for the art of dialectics, which has to judge what conceptions can and what cannot be joined together. Plato illustrates here by taking the conceptions of being, motion (becoming), and rest (existence), and showing what are the results of the combinations of these ideas. The conceptions of motion and rest cannot well be joined together, though both of them may be joined with that of being, since both are; the conception of rest is therefore in reference to itself a being, but in reference to the conception of motion a not-being or different. Thus the Platonic doctrine of ideas, after having in the Theatætus attained its general foundation in fixing the objective reality of conceptions, becomes now still farther developed in the Sophist to a doctrine of the agreement and disagreement of conceptions. The category which conditions these reciprocal relations is that of not-being or difference. This fundamental thought of the Sophist, that being is not without not-being and not-being is not without being, may be expressed in modern phraseology thus: negation is not not-being but determinateness, and on the other hand all determinateness and concreteness of conceptions, or every thing affirmative can be only through negation; in other words the conception of contradiction is the soul of a philosophical method.