When Socrates said to a young man who was introduced to him to have his capabilities tested, "Talk in order that I may see you," if indeed by "seeing" he did not simply mean "hearing," he was right, so far as it is only in conversation that the features and especially the eyes become animated, and the intellectual resources and capacities set their mark upon the countenance. This puts us in a position to form a provisional notion of the degree and capacity of intelligence; which was in that case Socrates' aim. But in this connection it is to be observed, firstly, that the rule does not apply to moral qualities, which lie deeper, and in the second place, that what from an objective point of view we gain by the clearer development of the countenance in conversation, we lose from a subjective standpoint on account of the personal relation into which the speaker at once enters in regard to us, and which produces a slight fascination, so that, as explained above, we are not left impartial observers. Consequently from the last point of view we might say with greater accuracy, "Do not speak in order that I may see you."
For to get a pure and fundamental conception of a man's physiognomy, we must observe him when he is alone and left to himself. Society of any kind and conversation throw a reflection upon him which is not his own, generally to his advantage; as he is thereby placed in a state of action and reaction which sets him off. But alone and left to himself, plunged in the depths of his own thoughts and sensations, he is wholly himself, and a penetrating eye for physiognomy can at one glance take a general view of his entire character. For his face, looked at by and in itself, expresses the keynote of all his thoughts and endeavors, the arrêt irrevocable, the irrevocable decree of his destiny, the consciousness of which only comes to him when he is alone.
The study of physiognomy is one of the chief means of a knowledge of mankind, because the cast of a man's face is the only sphere in which his arts of dissimulation are of no avail, since these arts extended only to that play of feature which is akin to mimicry. And that is why I recommend such a study to be undertaken when the subject of it is alone and given up to his own thoughts, and before he is spoken to: and this partly for the reason that it is only in such a condition that inspection of the physiognomy pure and simple is possible, because conversation at once lets in a pathognomical element, in which a man can apply the arts of dissimulation which he has learned: partly again because personal contact, even of the very slightest kind, gives a certain bias and so corrupts the judgment of the observer.
And in regard to the study of physiognomy in general, it is further to be observed that intellectual capacity is much easier of discernment than moral character. The former naturally takes a much more outward direction, and expresses itself not only in the face and the play of feature, but also in the gait, down even to the very slightest movement. One could perhaps discriminate from behind between a blockhead, a fool and a man of genius. The blockhead would be discerned by the torpidity and sluggishness of all his movements: folly sets its mark upon every gesture, and so does intellect and a studious nature. Hence that remark of La Bruyère that there is nothing so slight, so simple or imperceptible but that our way of doing it enters in and betrays us: a fool neither comes nor goes, nor sits down, nor gets up, nor holds his tongue, nor moves about in the same way as an intelligent man. (And this is, be it observed by way of parenthesis, the explanation of that sure and certain instinct which, according to Helvetius, ordinary folk possess of discerning people of genius, and of getting out of their way.)
The chief reason for this is that, the larger and more developed the brain, and the thinner, in relation to it, the spine and nerves, the greater is the intellect; and not the intellect alone, but at the same time the mobility and pliancy of all the limbs; because the brain controls them more immediately and resolutely; so that everything hangs more upon a single thread, every movement of which gives a precise expression to its purpose.
This is analogous to, nay, is immediately connected with the fact that the higher an animal stands in the scale of development, the easier it becomes to kill it by wounding a single spot. Take, for example, batrachia: they are slow, cumbrous and sluggish in their movements; they are unintelligent, and, at the same time, extremely tenacious of life; the reason of which is that, with a very small brain, their spine and nerves are very thick. Now gait and movement of the arms are mainly functions of the brain; our limbs receive their motion and every little modification of it from the brain through the medium of the spine.
This is why conscious movements fatigue us: the sensation of fatigue, like that of pain, has its seat in the brain, not, as people commonly suppose, in the limbs themselves; hence motion induces sleep.
On the other hand those motions which are not excited by the brain, that is, the unconscious movements of organic life, of the heart, of the lungs, etc., go on in their course without producing fatigue. And as thought, equally with motion, is a function of the brain, the character of the brain's activity is expressed equally in both, according to the constitution of the individual; stupid people move like lay-figures, while every joint of an intelligent man is eloquent.
But gesture and movement are not nearly so good an index of intellectual qualities as the face, the shape and size of the brain, the contraction and movement of the features, and above all the eye,—from the small, dull, dead-looking eye of a pig up through all gradations to the irradiating, flashing eyes of a genius.
The look of good sense and prudence, even of the best kind, differs from that of genius, in that the former bears the stamp of subjection to the will, while the latter is free from it.