7. Plato agrees partially with certain 'surly or fastidious' philosophers, as he terms them, who defined pleasure to be the absence of pain. They are also described as eminent in physics. There is unfortunately no school of Greek philosophy known to us which combined these two characteristics. Antisthenes, who was an enemy of pleasure, was not a physical philosopher; the atomists, who were physical philosophers, were not enemies of pleasure. Yet such a combination of opinions is far from being impossible. Plato's omission to mention them by name has created the same uncertainty respecting them which also occurs respecting the 'friends of the ideas' and the 'materialists' in the Sophist.
On the whole, this discussion is one of the least satisfactory in the dialogues of Plato. While the ethical nature of pleasure is scarcely considered, and the merely physical phenomenon imperfectly analysed, too much weight is given to ideas of measure and number, as the sole principle of good. The comparison of pleasure and knowledge is really a comparison of two elements, which have no common measure, and which cannot be excluded from each other. Feeling is not opposed to knowledge, and in all consciousness there is an element of both. The most abstract kinds of knowledge are inseparable from some pleasure or pain, which accompanies the acquisition or possession of them: the student is liable to grow weary of them, and soon discovers that continuous mental energy is not granted to men. The most sensual pleasure, on the other hand, is inseparable from the consciousness of pleasure; no man can be happy who, to borrow Plato's illustration, is leading the life of an oyster. Hence (by his own confession) the main thesis is not worth determining; the real interest lies in the incidental discussion. We can no more separate pleasure from knowledge in the Philebus than we can separate justice from happiness in the Republic.
IV. An interesting account is given in the Philebus of the rank and order of the sciences or arts, which agrees generally with the scheme of knowledge in the Sixth Book of the Republic. The chief difference is, that the position of the arts is more exactly defined. They are divided into an empirical part and a scientific part, of which the first is mere guess-work, the second is determined by rule and measure. Of the more empirical arts, music is given as an example; this, although affirmed to be necessary to human life, is depreciated. Music is regarded from a point of view entirely opposite to that of the Republic, not as a sublime science, coordinate with astronomy, but as full of doubt and conjecture. According to the standard of accuracy which is here adopted, it is rightly placed lower in the scale than carpentering, because the latter is more capable of being reduced to measure.
The theoretical element of the arts may also become a purely abstract science, when separated from matter, and is then said to be pure and unmixed. The distinction which Plato here makes seems to be the same as that between pure and applied mathematics, and may be expressed in the modern formula – science is art theoretical, art is science practical. In the reason which he gives for the superiority of the pure science of number over the mixed or applied, we can only agree with him in part. He says that the numbers which the philosopher employs are always the same, whereas the numbers which are used in practice represent different sizes or quantities. He does not see that this power of expressing different quantities by the same symbol is the characteristic and not the defect of numbers, and is due to their abstract nature; – although we admit of course what Plato seems to feel in his distinctions between pure and impure knowledge, that the imperfection of matter enters into the applications of them.
Above the other sciences, as in the Republic, towers dialectic, which is the science of eternal Being, apprehended by the purest mind and reason. The lower sciences, including the mathematical, are akin to opinion rather than to reason, and are placed together in the fourth class of goods. The relation in which they stand to dialectic is obscure in the Republic, and is not cleared up in the Philebus.
V. Thus far we have only attained to the vestibule or ante-chamber of the good; for there is a good exceeding knowledge, exceeding essence, which, like Glaucon in the Republic, we find a difficulty in apprehending. This good is now to be exhibited to us under various aspects and gradations. The relative dignity of pleasure and knowledge has been determined; but they have not yet received their exact position in the scale of goods. Some difficulties occur to us in the enumeration: First, how are we to distinguish the first from the second class of goods, or the second from the third? Secondly, why is there no mention of the supreme mind? Thirdly, the nature of the fourth class. Fourthly, the meaning of the allusion to a sixth class, which is not further investigated.
(I) Plato seems to proceed in his table of goods, from the more abstract to the less abstract; from the subjective to the objective; until at the lower end of the scale we fairly descend into the region of human action and feeling. To him, the greater the abstraction the greater the truth, and he is always tending to see abstractions within abstractions; which, like the ideas in the Parmenides, are always appearing one behind another. Hence we find a difficulty in following him into the sphere of thought which he is seeking to attain. First in his scale of goods he places measure, in which he finds the eternal nature: this would be more naturally expressed in modern language as eternal law, and seems to be akin both to the finite and to the mind or cause, which were two of the elements in the former table. Like the supreme nature in the Timaeus, like the ideal beauty in the Symposium or the Phaedrus, or like the ideal good in the Republic, this is the absolute and unapproachable being. But this being is manifested in symmetry and beauty everywhere, in the order of nature and of mind, in the relations of men to one another. For the word 'measure' he now substitutes the word 'symmetry,' as if intending to express measure conceived as relation. He then proceeds to regard the good no longer in an objective form, but as the human reason seeking to attain truth by the aid of dialectic; such at least we naturally infer to be his meaning, when we consider that both here and in the Republic the sphere of nous or mind is assigned to dialectic. (2) It is remarkable (see above) that this personal conception of mind is confined to the human mind, and not extended to the divine. (3) If we may be allowed to interpret one dialogue of Plato by another, the sciences of figure and number are probably classed with the arts and true opinions, because they proceed from hypotheses (compare Republic). (4) The sixth class, if a sixth class is to be added, is playfully set aside by a quotation from Orpheus: Plato means to say that a sixth class, if there be such a class, is not worth considering, because pleasure, having only gained the fifth place in the scale of goods, is already out of the running.
VI. We may now endeavour to ascertain the relation of the Philebus to the other dialogues. Here Plato shows the same indifference to his own doctrine of Ideas which he has already manifested in the Parmenides and the Sophist. The principle of the one and many of which he here speaks, is illustrated by examples in the Sophist and Statesman. Notwithstanding the differences of style, many resemblances may be noticed between the Philebus and Gorgias. The theory of the simultaneousness of pleasure and pain is common to both of them (Phil. Gorg.); there is also a common tendency in them to take up arms against pleasure, although the view of the Philebus, which is probably the later of the two dialogues, is the more moderate. There seems to be an allusion to the passage in the Gorgias, in which Socrates dilates on the pleasures of itching and scratching. Nor is there any real discrepancy in the manner in which Gorgias and his art are spoken of in the two dialogues. For Socrates is far from implying that the art of rhetoric has a real sphere of practical usefulness: he only means that the refutation of the claims of Gorgias is not necessary for his present purpose. He is saying in effect: 'Admit, if you please, that rhetoric is the greatest and usefullest of sciences: – this does not prove that dialectic is not the purest and most exact.' From the Sophist and Statesman we know that his hostility towards the sophists and rhetoricians was not mitigated in later life; although both in the Statesman and Laws he admits of a higher use of rhetoric.
Reasons have been already given for assigning a late date to the Philebus. That the date is probably later than that of the Republic, may be further argued on the following grounds: – 1. The general resemblance to the later dialogues and to the Laws: 2. The more complete account of the nature of good and pleasure: 3. The distinction between perception, memory, recollection, and opinion which indicates a great progress in psychology; also between understanding and imagination, which is described under the figure of the scribe and the painter.