3. Physics

The natural philosophy of Epicurus is based on the above foundation; but an aspect of interest is given it by the fact that it is still peculiarly the method of our times; his thoughts on particular aspects of Nature are, however, in themselves feeble and of little weight, containing nothing but an ill-considered medley of all manner of loose conceptions. Going further, the principle of the manner in which Epicurus looks on nature, lies in the conceptions he forms, which we have already had before us (pp. 282, 285). That is to say, the general representations which we receive through the repetition of several perceptions, and to which we relate such perceptions in forming an opinion, must be then applied to that which is not exactly matter of perception, but yet has something in common with what we can perceive. In this way it comes about that by such images we can apprehend the unknown which does not lend itself immediately to perception; for from what is known we must argue to what is unknown. This is nothing else but saying that Epicurus judged by analogy, or that he makes so-called evidence the principle of his view of Nature; and this is the principle which to this day has authority in ordinary physical science. We go through experiences and make observations, these arising from the sensuous perceptions which are apt to be overlooked. Thus we reach general concepts, laws, forces, and so on, electricity and magnetism, for instance, and these are then applied by us to such objects and activities as we cannot ourselves directly perceive. As an example, we know about the nerves and their connection with the brain; in order that there may be feeling and so on, it is said that a transmission from the finger-tips to the brain takes place. But how can we represent this to ourselves? We cannot make it a matter of observation. By anatomy we can lay bare the nerves, it is true, but not the manner of their working. We represent these to ourselves on the analogy of other phenomena of transmission, for instance as the vibration of a tense string that passes through the nerves to the brain. As in the well-known phenomenon of a number of billiard balls set close together in a row, the last of which rolls away when the first is struck, while those in the middle, through each of which the effect of the stroke has been communicated to the next, scarcely seem to move, so we represent to ourselves the nerves as consisting of tiny balls which are invisible even through the strongest magnifying glass, and fancy that at every touch, &c., the last springs off and strikes the soul. In the same way light is represented as filaments, rays, or as vibrations of the ether, or as globules of ether, each of which strikes on the other. This is an analogy quite in the manner of Epicurus.

In giving such explanations as those above, Epicurus professed to be most liberal, fair and tolerant, saying that all the different conceptions which occur to us in relation to sensuous objects—at our pleasure, we may say,—can be referred to that which we cannot ourselves directly observe; we should not assert any one way to be the right one, for many ways may be so. In so saying, Epicurus is talking idly; his words fall on the ear and the fancy, but looked on more narrowly they disappear. So, for instance, we see the moon shine, without being able to have any nearer experience of it. On this subject Epicurus says: “The moon may have its own light, or a light borrowed from the sun; for even on earth we see things which shine of themselves, and many which are illuminated by others. Nothing hinders us from observing heavenly things in the light of various previous experiences, and from adopting hypotheses and explanations in accordance with these. The waxing and waning of the moon may also be caused by the revolution of this body, or through changes in the air” (according as vapour is modified in one way or another), “or also by means of adding and taking away somewhat: in short, in all the ways whereby that which has a certain appearance to us is caused to show such appearance.” Thus there are to be found in Epicurus all these trivialities of friction, concussion, &c., as when he gives his opinion of lightning on the analogy of how we see fire of other kinds kindled: “Lightning is explained by quite a large number of possible conceptions; for instance, that through the friction and collision of clouds the figuration of fire is emitted, and lightning is produced.” In precisely the same way modern physicists transfer the production of an electric spark, when glass and silk are rubbed against each other, to the clouds. For, as we see a spark both in lightning and electricity, we conclude from this circumstance common to both that the two are analogical; therefore, we come to the conclusion that lightning also is an electric phenomenon. But clouds are not hard bodies, and by moisture electricity is more likely to be dispersed; therefore, such talk has just as little truth in it as the fancy of Epicurus. He goes on to say: “Or lightning may also be produced by being expelled from the clouds by means of the airy bodies which form lightning—by being struck out when the clouds are pressed together either by each other or by the wind,” &c. With the Stoics things are not much better. Application of sensuous conceptions according to analogy is often termed comprehension or explanation, but in reality there is in such a process not the faintest approach to thought or comprehension. “One man,” adds Epicurus, “may select; one of these modes, and reject the others, not considering what is possible for man to know, and what is impossible, and therefore striving to attain to a knowledge of the unknowable.”

This application of sensuous images to what has a certain similarity to them, is pronounced to be the basis and the knowledge of the cause, because, in his opinion, a transference such as this cannot be corroborated by the testimony of mere immediate sensation; thus the Stoic method of seeking a basis in thought is excluded, and in this respect the mode of explanation adopted by Epicurus is directly opposed to that of the Stoics. One circumstance which strikes us at once in Epicurus is the lack of observation and experience with regard to the mutual relations of bodies: but the kernel of the matter, the principle, is nothing else than the principle of modern physics. This method of Epicurus has been attacked and derided, but on this score no one need be ashamed of or fight shy of it, if he is a physicist; for what Epicurus says is not a whit worse than what the moderns assert. Indeed, in the case of Epicurus the satisfactory assurance is likewise always present of his emphasizing the fact most strongly that just because the evidence of the senses is found to be lacking, we must not take our stand on any one analogy. Elsewhere he in the same way makes light of analogy, and when one person accepts this possibility and another that other possibility, he admires the cleverness of the second and troubles himself little about the explanation given by the first; it may be so, or it may not be so. This is a method devoid of reason, which reaches no further than to general conceptions. Nevertheless, if Physical Science is considered to relate to immediate experience on the one hand, and, on the other hand—in respect of that which cannot be immediately experienced—to relate to the application of the above according to a resemblance existing between it and that which is not matter of experience, in that case Epicurus may well be looked on as the chief promoter, if not the originator of this method, and also as having asserted that it is identical with knowledge. Of the Epicurean method in philosophy we may say this, that it likewise has a side on which it possesses value, and we may in some measure assent when we hear, as we frequently do, the Epicurean physics favourably spoken of. Aristotle and the earlier philosophers took their start in natural philosophy from universal thought a priori, and from this developed the Notion; this is the one side. The other side, which is just as necessary, demands that experience should be worked up into universality, that laws should be found out; that is to say, that the result which follows from the abstract Idea should coincide with the general conception to which experience and observation have led up. The a priori is with Aristotle, for instance, most excellent but not sufficient, because to it there is lacking connection with and relation to experience and observation. This leading up of the particular to the universal is the finding out of laws, natural forces, and so on. It may thus be said that Epicurus is the inventor of empiric Natural Science, of empiric Psychology. In contrast to the Stoic ends, conceptions of the understanding, experience is the present as it appears to the senses: there we have abstract limited understanding, without truth in itself, and therefore without the present in time and the reality of Nature; here we have this sense of Nature, which is more true than these other hypotheses.

The same effect which followed the rise of a knowledge of natural laws, &c., in the modern world was produced by the Epicurean philosophy in its own sphere, that is to say, in so far as it is directed against the arbitrary invention of causes. The more, in later times, men made acquaintance with the laws of Nature, the more superstition, miracles, astrology, &c. disappeared; all this fades away owing to the contradiction offered to it by the knowledge of natural laws. The method of Epicurus was directed more especially against the senseless superstition of astrology, &c., in whose methods there is neither reason nor thought, for it is quite a thing of the imagination, downright fabrication being resorted to, or what we may even term lying. In contrast with this, the way in which Epicurus works, when the conceptions and not thought are concerned, accords with truth. For it does not go beyond what is perceived by the sight, and hearing, and the other senses, but keeps to what is present and not alien to the mind, not speaking of certain things as if they could be seen and heard, when that is quite impossible, seeing that the things are pure inventions. The effect of the Epicurean philosophy in its own time was therefore this, that it set itself against the superstition of the Greeks and Romans, and elevated men above it. All the nonsense about birds flying to right or to left, or a hare running across the path, or men deciding how they are to act according to the entrails of animals, or according as chickens are lively or dull—all that kind of superstition the Epicurean philosophy made short work of, by permitting that only to be accepted as truth which is counted as true by sense perception through the instrumentality of anticipations; and from it more than anything those conceptions which have altogether denied the supersensuous have proceeded. The physics of Epicurus were therefore famous for the reason that they introduced more enlightened views in regard to what is physical, and banished the fear of the gods. Superstition passes straightway from immediate appearances to God, angels, demons; or it expects from finite things other effects than the conditions admit of, phenomena of a higher kind. To this the Epicurean natural philosophy is utterly opposed, because in the sphere of the finite it refuses to go beyond the finite, and admits finite causes alone; for the so-called enlightenment is the fact of remaining in the sphere of the finite. There connection is sought for in other finite things, in conditions which are themselves conditioned; superstition, on the contrary, rightly or wrongly, passes at once to what is above us. However correct the Epicurean method may be in the sphere of the conditioned, it is not so in other spheres. Thus if I say that electricity comes from God, I am right and yet wrong. For if I ask for a cause in this same sphere of the conditioned, and give God as answer, I say too much; though this answer fits all questions, since God is the cause of everything, what I would know here is the particular connection of the phenomenon. On the other hand, in this sphere even the Notion is already something higher; but this loftier way of looking at things which we met with in the earlier philosophers, was quite put an end to by Epicurus, since with superstition there also passed away self-dependent connection and the world of the Ideal.

To the natural philosophy of Epicurus there also belongs his conception of the soul, which he looks on as having the nature of a thing, just as the theories of our own day regard it as nerve-filaments, cords in tension, or rows of minute balls (p. 294). His description of the soul has therefore but little meaning, since here also he draws his conclusion by analogy, and connects therewith the metaphysical theory of atoms: “The soul consists of the finest and roundest atoms, which are something quite different from fire, being a fine spirit which is distributed through the whole aggregate of the body, and partakes of its warmth.” Epicurus has consequently established a quantitative difference only, since these finest atoms are surrounded by a mass of coarser atoms and dispersed through this larger aggregate. “The part which is devoid of reason is dispersed in the body” as the principle of life, “but the self-conscious part (τὸ λογικόν) is in the breast, as may be perceived from joy and sadness. The soul is capable of much change in itself, owing to the fineness of its parts, which can move very rapidly: it sympathizes with the rest of the aggregate, as we see by the thoughts, emotions and so on; but when it is taken away from us we die. But the soul, on its part, has also the greatest sympathy with sensuous perception; yet it would have nothing in common with it, were it not in a certain measure covered by the rest of the aggregate” (the body)—an utterly illogical conception. “The rest of this aggregate, which this principle provides for the soul, is thereby also partaker, on its part, of a like condition” (sensuous perception), “yet not of all that the former possesses; therefore, when the soul escapes, sensuous perception exists no more for it. The aggregate spoken of above has not this power in itself, but derives it from the other which is brought into union with it, and the sentient movement comes to pass through the flow of sympathy which they have in common.” Of such conceptions it is impossible to make anything. The above-mentioned (p. 287) interruption of the streaming together of images of external things with our organs, as the ground of error, is now explained by the theory that the soul consists of peculiar atoms, and the atoms are separated from one another by vacuum. With such empty words and meaningless conceptions we shall no longer detain ourselves; we can have no respect for the philosophic thoughts of Epicurus, or rather he has no thoughts for us to respect.