Because of his close connection with Leucippus, Democritus is sometimes classed among the pre-Socratics, and in fact it is probable that he began "philosophizing" before Socrates did. Nevertheless he belongs to the age of Socrates and the sophists rather than to the age of pure "inquiry." He was a fellow-citizen of the great sophist Protagoras, and, like Socrates, he was interested not only in nature but in man. Born about 460 B.C., he lived to the age of ninety. According to tradition he traveled widely, but spent most of his life in his native city of Abdera in Thrace, where he had a "school" of philosophy. His great learning earned him the nickname of "Wisdom," and in later times, presumably because of his ethical theory of "cheerfulness," he was known as "the laughing philosopher." His writings, only fragments of which survive, seem to have covered every branch of learning, including the "modern" subjects of ethics, psychology and logic. He was indeed the Aristotle of his age, and Aristotle himself often alludes to his views. Curiously enough, Plato never mentions him — an unfortunate oversight, since Democritus may be regarded as the founder of materialism.
Democritus took over from Leucippus the basic theory of atomism and elaborated it so as to form a system designed to answer not only the original question of Thales but many others as well — in particular, perhaps, the question "How do we know anything?". The ultimate realities are, of course, atoms and the void. The atoms are all of the same substance, indivisible, infinite in number and infinitely various in shape. Presumably in order to make an infinite variety of shape possible, Democritus adds that they are indefinite in size. Some atoms, he says, can be "very large." The Nothing, which, though unreal, exists, is also infinite and the objects of sense are formed by the constant movement, and "vibration" of atoms in the void. Democritus seems to assume that motion is an eternal characteristic of the atoms, something which depends on "Necessity." By "Necessity" he means nothing more or less than "the nature of things" or "natural law." It seems therefore somewhat unfair of Aristotle to blame the atomists for not producing a cause for this motion. To them the motion is the cause of everything.
Atoms, differing from each other only in shape and size, can be arranged or placed in an infinite variety of ways. Their motions too in the void can be infinitely various, as they collide, bounce off each other, or become entangled in more or less temporary complexes. Nothing else exists. Yet out of these colorless, insensitive, indivisible, unintelligent and (except possibly in the case of the "very large" atoms) imperceptible objects has been evolved the whole world of our thought, sense and experience. The differences which we observe — e.g., differences between the animate and the inanimate, between the colored and the colorless, soft and hard, hot and cold — proceed solely from the various shapes and arrangements of the atoms and the density or lack of density of their conglomerations. They can indeed proceed from nothing else. It is, it seems, for this reason that Democritus (or Leucippus or both) states that our only "legitimate" knowledge is of the atoms and the void. Other knowledge — the knowledge which comes to us through the senses — is "bastard." Not, by any means, that the evidence of the senses is to be rejected. It is expressly stated that "the phenomenon is true." But the truth behind phenomena — namely, the atoms and the void — is not accessible to the senses. They are a "legitimate" inference from the evidence of the senses and are quite certainly true, whereas in the realm of phenomena opinions may be misplaced or misdirected, even though the particular phenomenon itself is always true. This is an attitude that is far removed from scepticism. We have certainly such fragments as "We know nothing truly; for truth is in the depths," and "sweet is by convention, hot by convention, cold by convention, color by convention; in truth are atoms and the void." But these sayings do not necessarily imply that sensation is unreliable. The "conventions" are, after all, all that we have to go by and it would seem that Democritus is emphasizing this fact rather than making a confession of scepticism when he imagines the senses as addressing the mind as follows: "Wretched mind, it was from us that you received your beliefs and do you now attempt to overthrow us? Your victory would mean your own downfall."
As for the mind itself, or soul (Democritus makes no distinction between the two), it also is, of course, material. It is assumed to be made of particularly round "fiery" atoms which are distributed over the body. It is through these atoms that we receive the impressions or "idols" of exterior things. Everything is constantly throwing off "idols" (a development of Empedocles' "effluences") and these "idols" make contact with the soul atoms whether through touch on the surface of the body or through eye, ear, nose or tongue. So much for ordinary sensation. But there is a particular kind of sensation which we call thought. This sensation may be referred to the mind; for, though the mind and the soul are "the same" in the sense that they are composed of the same round atoms, there is a particularly dense concentration of these atoms in the breast. "Idols" cannot pass through this dense concentration without moving the soul — or mind — atoms. Hence thought.
The theory is a complicated one. In a short summary it is impossible to do justice to it. A full and excellent account is to be found in Cyril Bailey's authoritative work, The Greek Atomists and Epicurus. Here, too, there is no space to attempt to describe Democritus' cosmogony, his theory of the coming into being of innumerable worlds by means of the action of a "whirl." It is clear however that the creation and dissolution of worlds as of everything else is the work of "Necessity." Where Democritus speaks of "chance" he merely means a mechanical cause which to us is unknown. Everything has a mechanical cause in the movements of the atoms in the void.
To us such a view of the universe seems to imply atheism in religion and determinism in morals; but, as we shall see most clearly in the case of Epicurus, these were not the conclusions reached by the Greek atomists. As for Democritus we lack the evidence to say precisely what were his views of the gods. He seems to have believed that certain "idols" of very great size (his obsession with the very large is remarkable) did appear to men. These were "difficult to be destroyed, but not indestructible." They were certainly mere products of the atoms and the void — parts of nature, rather than controllers or inspirers of it.
With regard to Democritus' ethical theory what surprises us most is that in spite of his mechanistic theory of reality he seems not to have been concerned at all with the problem of free will and determinism. He assumes free will to exist and proceeds to elaborate a doctrine of "cheerfulness" as being the aim of a good life. By "cheerfulness" he seems to mean the contented, balanced and undismayed attitude of a sensible and prudent Greek of his age. His "cheerfulness" is not the same as the "pleasure" of Epicurus; he accepts the ordinary conventions, such as the importance of the political life. Some of his precepts remind one of the system of Epicurus, but it is quite impossible to say of him, as one must say of Epicurus, that his ethical theory is logically connected with his general system of materialism.
Epicurus, writing more than a hundred years after Democritus (his dates are 342/1-271/70 B.C.) was nothing if not a systematizer. He is sometimes represented as a moralist who, needing a philosophical background to his ethical theories, took over the atomic theory of Democritus and Leucippus and simply tacked it on to his own program of the good life. Cyril Bailey in his study of Epicurus has convincingly shown that this view of the matter is thoroughly mistaken. Epicurus is one of the most consistent thinkers who has ever lived and, far from taking over uncritically the doctrine of Democritus, he made considerable alterations in it — usually, it is true, in order to bring it into a line with his own ethical theory. Thus he founded one of the two philosophical systems which, from the end of the fourth century B.C.) almost until the triumph of Christianity, continued to dominate the minds of the educated. Both Stoicism and Epicureanism can be called "creeds" as well as "philosophies." They were designed not only to explain nature, as thinkers from Thales to Democritus had attempted to do, but to satisfy a modern kind of scepticism which had arisen, at least in part, as the result of historical events. Chief of these events, as was suggested above, was the decline and fall of the authority of Athens and the other Greek city-states. In the world of the successors of Alexander it was no longer possible to think like Socrates or even like Plato, for now there was a sense in which politics did not matter. "The city," both as a practical reality and as an ideal, had ceased to exist. The individual, freed from his dependence on the city, had in a way, perhaps, gained wider horizons; in another way he had become disoriented and was in danger of being lost in a world too big for him either to control or to understand. What he needed was assurance in the ordinary operations of life and it was this assurance which Epicurus attempted to give him. Epicurus has been described by Cyril Bailey as "the apostle of common sense." He commends the quiet life. Yet it would be wrong to suppose that his creed is lacking in intellectual acuteness or that it is a mere expression of quietism. Neither Julius Caesar nor his assassin, Cassius, was a quietist.
Epicurus himself protested rather too much about his originality. He speaks slightingly of Democritus and calls the Democritean philosopher Nausiphanes, under whom he studied in his youth, "the mollusc." In spite of his own enormous philosophical output (he is said to have been the author of three hundred rolls) he was contemptuous of the productions of others and of all education other than that which he himself could afford. His advice to his pupil Pythocles is "Blest youth, set sail in your bark and flee from every form of culture." Yet for thirty-six years he taught in the famous "Garden" in Athens and enjoyed the devoted affection of his pupils, both male and female (he was the first to allow women to become members of a school of philosophy). Most of his works have been lost, but we have a full and undoubtedly accurate account of his doctrine in the poem On Nature by the Roman poet Lucretius, a contemporary of Julius Caesar.
To Lucretius, Epicurus is the greatest benefactor that mankind has ever known. This is because he has freed man from fear — from fear of the gods and from fear of what may happen to one after death. He has done this noble work quite simply, by explaining everything. There is no longer any room for doubt or perplexity. The nature of things is known and can be explained to anyone who is intelligent enough to listen to the argument.
In fact the argument is often extremely complicated, but it is extraordinarily consistent. It is based on a thoroughgoing belief in sensation as the only basis of knowledge. There is no question of a distinction between appearance and reality. Appearance is reality. Nor is there any basic distinction such as we have noticed in Democritus between thought and sensation. Epicurus does not accept Democritus' view that "legitimate" knowledge is confined to atoms and the void and that our knowledge of the "secondary qualities" is "by convention." To him the only "legitimate" knowledge is sensation, thought itself being a kind of sensation. True that both the mind and the senses can be, as it were, directed. The senses can be concentrated in attention; the mind can form an opinion. But both processes are purely material. If we can find sensations which will corroborate an opinion, or at least will not witness against it, then the opinion is true; otherwise it is false. This certainly may be described as the logic of common sense and Epicurus, using great ingenuity in attempting to solve obvious difficulties, never departs from it. He will soon insist that the sun and moon are "about the same size" as they appear to us to be.
For the basis of his all-embracing system he adopted the theories of Leucippus and Democritus, but he made, in the interests of his common-sense, sensational view of things, important alterations in these theories. Atoms and the void are accepted as the ultimate realities. They are, indeed, imperceptible, but, so far from being "witnessed against" by our perceptions, they are confirmed by a number of analogies from sensation and they account for sensation itself, which is always the result of corporeal contact.
With regard to the atoms themselves Epicurus again takes up a more common-sense view than that of Democritus. He observes that weight is a property of sensible objects and so he adds weight to the primary properties of the atoms and makes weight the cause of their movement. Their natural tendency is, he assumes, to fall "downwards" in space. But a stream of particles moving in parallel straight lines at a uniform velocity obviously would continue in this state for all eternity. To account for atomic combinations Epicurus asserts that at any moment any atom may, for no known reason, deviate slightly from its course. As a result of this slight deviation it will come into collision with other atoms and so give rise to the whole complex of movement out of which all things are made. This particular theory of Epicurus is, of course, lamentable from the point of view of a scientist. Whereas Democritus had created a beautifully simple system in which atoms in motion in the void could be held to account for everything and no other "cause" need be looked for, Epicurus now introduces in "the slight swerve" a new element of causation which has the disadvantage of being absolutely unpredictable and unexplainable. Yet again Epicurus is, in his own way, consistent. He has observed that if the determinism of Democritus is to be thoroughly thought out, there is no place for free will. Yet free will is a fact of experience. Either, therefore, it must be accounted for by supposing that there is something or other in "the soul" which is not atomic, or else the atoms themselves must be assumed to have the power of "free" movement. The first alternative would be disastrous to the whole theory of materialism; therefore the second, which is confirmed by an analogy from sensation, must be true.
This doctrine of "the slight swerve" is the most interesting of the alterations made by Epicurus in the theory of Democritus. There are others as well. He dismisses, for example, the possibility that there can be "very large" atoms. If there were, we should be able to see them. Moreover it is very hard to think of something visible which is also indivisible. Epicurus also elaborates in great detail the views of Democritus on the soul, on compound bodies and on perception. His great influence, however, undoubtedly derives chiefly from his moral theories. Physics are an essential background to these, but the real aim remains freedom from fear and freedom from pain.
One is freed from fear of death when one realizes the truth about the corporeal structure of the soul and how it is impossible for it to exist after the death of the body. As for the gods, so far from causing us terror, they are most agreeable objects to contemplate. They certainly exist, as is shown by the "idols" which frequently visit men, particularly in sleep. But it can easily be demonstrated that they have nothing whatever to do with human affairs. They are far too happy to bother about us and they live, not in any recognizable heaven, but in the "spaces between the worlds." Once again the theory is worked out in detail and from the final basis of sensation. There is no space here to examine the theory. It is a strangely anthropomorphic one and was worked out very fully by disciples of Epicurus, one of whom declares that the gods, being perfectly happy beings, must enjoy the pleasures of conversation and must be assumed to converse together either in Greek or in a language "not far removed from Greek."
Once freed from these great fears, it remains to decide how best to live our life. Here the fundamental principle is, according to Epicurus, simple and quite obvious. A moment's observation will show us that what men seek is pleasure and what they avoid is pain. There is no point in reasoning here. We are now dealing with the basis of all reasoning, with pure sensation. There is therefore no question at all that the "end" of life is pleasure and nothing else. Since the standard of "the good" is pleasure, no pleasure can be better or worse than another; it can only be greater or less. Again on the basis of sensation Epicurus comes to the conclusion that "the beginning and the root of all good is the pleasure of the stomach; even wisdom and culture must be referred back to this."
By so uncompromisingly following his first principles to their conclusions Epicurus certainly got himself a bad name. Yet the true Epicurean who followed the Master's precepts was very far from being an "epicure." The life of the profligate or the glutton was greatly frowned upon, not so much because such a life was "wrong" as because it was injudicious. An orgy of food and drink may produce most agreeable sensations, but it is, our frames being constituted as they are, liable to be followed by a hangover. Strict simplicity in diet is therefore recommended and was certainly enforced or accepted by the company of disciples who met in the Garden. So too with what are known as the virtues. There is no reason in the nature of things why a man should be good rather than bad — except the very good reason that he will experience more pleasure if he is good. A man's life is continuous and he will live it with least disturbance if he is content with simple pleasures, if he avoids passion, and if he does nothing which will occasion remorse. The final aim is not violent pleasures succeeded by correspondingly violent pains, but a condition of tranquillity or imperturbability. Means towards the attainment of this aim will be found in frugal living, in friendship, in the delights of conversation and even in the contemplation of the gods who, wisely, have nothing to do with humanity at all. We are recommended to avoid ambition, any form of public activity, marriage and the begetting of children. These are likely, in the long run, to cause us more pain than pleasure.
It is an egotistic creed, but it is an entirely consistent one. It can even be adjudged respectable, since Epicurus' own ideas of enlightened self-interest tend to observe the proprieties (except in so far as the begetting of children is concerned) and to support orderly and efficient government. One can go further still and claim for the system a kind of austerity like that of the Stoics. It was Epicurus and not a Stoic who proclaimed that the wise man could be happy even on the rack.
Yet it must be allowed that in ethics the Master's precepts do not quite harmonize with that common sense that is the general opinion of mankind (to which often he defers). Suppose a man to be gifted with a really remarkable digestion, we could not logically blame him for spending his whole life in eating and drinking. Suppose a man to be incapable of remorse and strong enough to evade punishment, there is no reason why he should not indulge himself in any kind of crime which is calculated to give him pleasure. More than two hundred years after the Master's death, when his ideas had become widely spread in Rome, we find on the one hand the ardent (even over-ardent) convert Lucretius and on the other hand such characters as Caesar and Cassius, whose notions of a quiet life were very different from those of Epicurus himself. This is certainly a sign of how wide was the appeal of materialism and of common sense. The appeal is equally wide today and many of us are, one would imagine, Epicureans without knowing it.
There has survived from antiquity a rather curious little "manual" of Epicureanism, which early became known as the Principal Doctrines. That it is the work of Epicurus himself has been disputed, but the balance of opinion now inclines to the view that it is. I have decided, therefore, to include it here, since its odd mixture of cautious good sense with a certain inhumanity conveys excellently the flavor of this important philosophical view.
Our only full and consecutive treatment of the doctrine of Epicurus is to be found in the poem of Lucretius, De Rerum Natura. It has seemed best, therefore, in the following pages to include several extracts from this great poem. It should be added that from a few extracts it is impossible to give an adequate idea of the complexity of argument and the fervor which sustain the whole work. I have ventured to translate one passage into verse in the hope that in this way the reader will be able to see more clearly how fervent was the resigned faith of some, at least, of the followers of Epicurus.