Timaeus — Plato

Plato and modern doctors. 413 of food. The freshest and acutest forms of triangles are those that TUnaeus. are found in children, but they become more obtuse with ad- Introducvancing years ; and when they finally wear out and fall to pieces, ^"^'^" old age and death supervene. . As in the Republic, Plato is still the enemy of the purgative treatment of physicians, which, except in extreme cases, no man of sense will ever adopt.

For, as he adds, with an insight into the truth, ' every disease is akin to the nature of the living being and is only irritated by stimulants. He is of opinion that nature should be left to herself, and is inclined to think that physicians are in vain (cp. Laws vi. 761 C — where he says that warm baths would be more beneficial to the limbs of the aged rustic than • the prescriptions of a not over-wise doctor).

If he seems to be extreme in his condemnation of medicine and to rely too much on diet and exercise, he might appeal to nearly all the best physicians of our own age in support of his opinions, who often speak to their patients of the worthlessness of drugs. For we ourselves are sceptical about medicine, and very unwilling to submit to the purgative treatment of physicians.

May we not claim for Plato an anticipation of modern ideas as about some questions of astronomy and physics, so also about medicine ? As in the Charmides (156, 157) he tells us that the body cannot be cured without the soul, so in the Timaeus he strongly asserts the sympathy of soul and body ; any defect of either is the occasion of the greatest discord and disproportion in the other.

Here too may be a presentiment that in the medicine of the future the interdependence of mind and body will be more fully recognized, and that the influence of the one over the other may be exerted in a manner which is not now thought possible. In Plato's explanation of sensation we are struck by the fact that he has not the same distinct conception of organs of sense which is familiar to ourselves.

The senses are not instruments, but rather passages, through which external objects strike upon the mind. The eye is the aperture through which the stream of vision passes, the ear is the aperture through which the vibrations of sound pass. But that the complex structure of the eye or the 2ear is in any sense the cause of sight and hearing he seems hardly to be aware. The process of sight is the most complicated (cp. Rep. vi. 507, 508), and consists of three elements — the light which is supposed to reside within the eye, the hght of the sun, and the light emitted from external objects.

When the light of the eye meets the light of the sun, and both together meet the light issuing from an external object, this is the simple act of sight. When the particles of light which proceed from the object are exactly equal to the particles of the visual ray which meet them from within, then the body is transparent. If they are larger and contract the visual ray, a black colour is produced; if they are smaller and dilate it, a white.

Other phenomena are produced by the variety and motion of light. A sudden flash of fire at once elicits light and moisture from the eye, and causes a bright colour. A more subdued light, on mingling with the moisture of the eye, produces a red colour. Out of these elements all other colours are derived. All of them are combinations of bright and red with white and black.

Plato himself tells us that he does not know in what proportions they combine, and he is of opinion that such knowledge is granted to the gods only. To have seen the affinity of them to each other and their connection with light, is not a bad basis for a theory of colours.

We must remember that they were not distinctly defined to his, as they are to our eyes ; he saw them, not as they are divided in the prism, or artificially manufactui:ed for the painter's use, but as they exist in nature, blended and confused with one another. We can hardly agree with him when he tells us that smells do not admit of kinds.

He seems to think that no definite qualities can attach to bodies which are in a state of transition or evaporation ; he also makes the subtle observation that smells must be denser than air, though thinner than water, because when there is an obstruction to the breathing, air can penetrate, but not smell. The affections peculiar to the tongue are of various kinds, and, like many other affections, are caused by contraction and dilation.

Some of them are produced by rough, others by abstergent, others by inflammatory substances, — these act upon the tasting instruments of the tongue, and produce a more or less disagreeable sensation, while other particles congenial to the tongue soften and 3harmonize them. The instruments of taste reach from the tongue Timncus. to the heart. Plato has a hvely sense of the manner in which Introducsensation and motion are communicated from one part of the body ^'°^" to the other, though he confuses the affections with the organs. Hearing is a blow which passes through the car and ends in the region of the liver, being transmitted by means of the air, the brain, and the blood to the soul.

The swifter sound is acute, the sound which moves slowly is grave. A great body of sound is loud, the opposite is low. Discord is produced by the swifter and slower motions of two sounds, and is converted into harmony when the swifter motions begin to pause and are overtaken by the slower. The general phenomena of sensation are partly internal, but the more violent are caused by conflict with external objects.

Proceeding by a method of superficial observation, Plato remarks that the more sensitive parts of tlie human frame are those which are least covered by flesh, as is the case with the head and the elbows. Man, if his head had been covered with a thicker pulp of flesh, might have been a longer-lived animal than he is, but could not have had as quick perceptions.

On the other hand, the tongue is one of the most sensitive of organs ; but then this is made, not to be a covering to the bones which contain the marrow or source of life, but with an express purpose, and in a separate mass (75 A). § 8. We have now to consider how far in any of these speculations Plato approximated to the discoveries of modern science.

The modern physical philosopher is apt to dwell exclusively on the absurdities of ancient ideas about science, on the hap-hazard fancies and a priori assumptions of ancient teachers, on their confusion of facts and ideas, on their inconsistency and blindness to the most obvious phenomena. He measures them not by what preceded them, but by what has followed them.

He does not consider that ancient physical philosophy was not a free enquiry, but a growth, in which the mind was passive rather than active, and was incapable of resisting the impressions which flowed in upon it. He hardly allows to the notions of the ancients the merit of being the stepping-stones by which he has himself risen