Nevertheless, there are not worlds of every possible form and shape.
Let us also beware of thinking that animals are derived from the infinite; for there is no one who can prove that the germs from which animals are born, and plants, and all the other objects which we contemplate, have been brought from the exterior in such a world, and that this same world would not have been able to produce them of itself. This remark applies particularly to the earth.
Again, we must admit that in many and various respects, nature is both instructed and constrained by circumstances themselves; and that reason subsequently makes perfect and enriches with additional discoveries the things which it has borrowed from nature; in some cases rapidly, and in others more slowly. And in some cases according to periods and times greater than those which proceed from the infinite; in other cases according to those which are smaller. So, originally it was only in virtue of express agreements that one gave names to things. But men whose ideas and passions varied according to their respective nations, formed these names of their own accord, uttering divers sounds produced by each passion, or by each idea, following the differences of the situations and of the peoples. At a later period one established in each nation, in a uniform manner, particular terms intended to render the relations more easy, and language more concise. Educated men introduced the notion of things not discoverable by the senses, and appropriated words to them when they found themselves under the necessity of uttering their thoughts; after this, other men, guided in every point by reason, interpreted these words in the same sense.
As to the heavenly phenomena, such as the motion and course of the stars, the eclipses, their rising and setting, and all other appearances of the same kind, we must beware of thinking that they are produced by any particular being which has regulated, or whose business it is to regulate for the future, the order of the world, a being immortal and perfectly happy; for the cares and anxieties, the benevolence and the anger, far from being compatible with felicity, are on the contrary the consequence of weakness, of fear, and of the want which a thing has of something else. We must not fancy either that these globes of fire, which roll on in space, enjoy a perfect happiness, and give themselves, with reflection and wisdom, the motions which they possess. But we must respect the established notions on this subject, provided, nevertheless, that they do not all contradict the respect due to truth; for nothing is more calculated to trouble the soul than this strife of contradictory notions and principles. We must therefore admit that from the first movement impressed on the heavenly bodies since the organization of the world there is derived a sort of necessity which regulates their course to this day.
Let us be well assured that it is to physiology that it belongs to determine the causes of the most elevated phenomena, and that happiness consists, above all things, in the science of the heavenly things and their nature, and in the knowledge of analogous phenomena which may aid us in the comprehension of the ethics. These heavenly phenomena admit of several explanations; they have no reason of a necessary character, and one may explain them in different manners. In a word, they have no relation—a moment’s consideration will prove this by itself—with those imperishable and happy natures which admit of no division and of no confusion. As for the theoretical knowledge of the rising and setting of the stars, of the movement of the sun between the tropics, of the eclipses, and all other similar phenomena, that is utterly useless as far as any influence upon happiness that it can have. Moreover, those who, though possessed of this knowledge, are ignorant of nature and of the most probable causes of the phenomena, are no more protected from fear than if they were in the most complete ignorance; they even experience the most lively fears, for the trouble, with which the knowledge of which they are possessed inspires them, can find no issue, and is not dissipated by a clear perception of the reasons of these phenomena.
As to us, we find many explanations of the motions of the sun, of the rising and setting of the stars, of the eclipses and similar phenomena, just as well as of the more particular phenomena. And one must not think that this method of explanation is not sufficient to procure happiness and tranquillity. Let us content ourselves with examining how it is that similar phenomena are brought about under our own eyes, and let us apply these observations to the heavenly objects and to everything which is not known but indirectly. Let us despise those people who are unable to distinguish facts susceptible of different explanations from others which can only exist and be explained in one single way. Let us disdain those men who do not know, by means of the different images which result from distance, how to give an account of the different appearances of things; who, in a word, are ignorant what are the objects which can excite any trouble in us. If, then, we know that such a phenomenon can be brought about in the same manner as another given phenomenon of the same character which does not inspire us with any apprehension; and if, on the other hand, we know that it can take place in many different manners, we shall not be more troubled at the sight of it than if we knew the real cause of it.
We must also recollect that that which principally contributes to trouble the spirit of men is the persuasion which they cherish that the stars are beings imperishable and perfectly happy, and that then one’s thoughts and actions are in contradiction to the will of these superior beings; they also, being deluded by these fables, apprehend an eternity of evils, they fear the insensibility of death, as that could affect them. What do I say? It is not even belief, but inconsiderateness and blindness which govern them in everything, to such a degree that, not calculating these fears, they are just as much troubled as if they had really faith in these vain phantoms. And the real freedom from this kind of trouble consists in being emancipated from all these things, and in preserving the recollection of all the principles which we have established, especially of the most essential of them. Accordingly, it is well to pay a scrupulous attention to existing phenomena and to the sensations, to the general sensations for general things, and to the particular sensations for particular things. In a word, we must take note of this, the immediate evidence with which each of these judicial faculties furnishes us; for, if we attend to these points, namely, whence confusion and fear arise, we shall divine the causes correctly, and we shall deliver ourselves from those feelings, tracing back the heavenly phenomena to their causes, and also all the others which present themselves at every step, and inspire the common people with extreme terror.
This, Herodotus, is a kind of summary and abridgment of the whole question of natural philosophy. So that, if this reasoning be allowed to be valid, and be preserved carefully in the memory, the man who allows himself to be influenced by it, even though he may not descend to a profound study of its details, will have a great superiority of character over other men. He will personally discover a great number of truths which I have myself set forth in my entire work; and these truths being stored in his memory, will be a constant assistance to him. By means of these principles, those who have descended into the details, and have studied the question sufficiently, will be able, in bringing in all their particular knowledge to bear on the general subject, to run over without difficulty almost the entire circle of the natural philosophy; those, on the other hand, who are not yet arrived at perfection, and who have not been able to hear me lecture on these subjects, will be able in their minds to run over the main of the essential notions, and to derive assistance from them for the tranquillity and happiness of life.
This then is his letter on physics.
About the heavenly bodies he writes thus:
Epicurus to Pythocles, Wishing He May Do Well
Cleon has brought me your letter, in which you continue to evince towards me an affection worthy of the friendship which I have for you. You devote all your care, you tell me, to engraving in your memory those ideas which contribute to the happiness of life; and you entreat me at the same time to send you a simple abridgment and abstract of my ideas on the heavenly phenomena, in order that you may without difficulty preserve the recollection of them. For, say you, what I have written on this subject in my other works is difficult to recollect, even with continual study.
I willingly yield to your desire, and I have good hope that in fulfilling what you ask, I shall be useful too to many others, especially to those who are as yet novices in the real knowledge of nature, and to those to whom the perplexities and the ordinary affairs of life leave but little leisure. Be careful then to seize on those precepts thoroughly, engrave them deeply in your memory, and meditate on them with the abridgment addressed to Herodotus, which I also send you.
Know then that it is with the knowledge of the heavenly phenomena, both with those which are spoken of in contact with one another, and of those which have a spontaneous existence, as with every other science; it has no other aim but that freedom from anxiety, and that calmness which is derived from a firm belief.
It is not good to desire what is impossible, and to endeavor to enunciate a uniform theory about everything; accordingly, we ought not here to adopt the method which we have followed in our researches into Ethics, or in the solution of problems of natural philosophy. We there said, for instance, that there are no other things except bodies and the vacuum, that the atoms are the principles of things, and so of the rest. In a word, we gave a precise and simple explanation of every fact, conformable to appearances.
We cannot act in the same way with respect to the heavenly phenomena: these productions may depend upon several different causes, and we may give many different explanations on this subject, equally agreeing with the impressions of the senses. Besides, it is not here a question about reasoning on new principles, and of laying down a priori rules for the interpretation of nature; the only guides for us to follow are the appearances themselves; for that which we have in view is not a set of systems and vain opinions, but much rather a life exempt from every kind of disquietude.
The heavenly phenomena do not inspire those, who give different explanations of them conformable with appearances, instead of explaining them by hypothesis, with any alarm. But if, abandoning hypothesis, one at the same time renounces the attempt to explain them by means of analogies founded on appearances, then one is placing oneself altogether at a distance from the science of nature, in order to fall into fables.
It is possible that the heavenly phenomena may present some apparent characters which appear to assimilate them to those phenomena which we see taking place around ourselves, without there being any real analogy at the bottom. For the heavenly phenomena may depend for their production on many different causes; nevertheless, we must observe the appearances presented by each, and we must distinguish the different circumstances which attach to them, and which can be explained in different manners by means of analogous phenomena which arise under our eyes.
The world is a collection of things embraced by the heaven, containing the stars, the earth, and all visible objects. This collection, separated from the infinite, is terminated by an extremity, which is either rare, or dense, or revolving, or in a state of repose, or of a round, or triangular, or of some shape or other in fact, for it may be of any shape, the dissolution of which must bring the destruction of everything which they embrace. In fact, it can take place in every sort of way, since there is not one of those things which are seen which testifies against this world in which we cannot detect any extremity; and that such worlds are infinite in number is easily seen, and also that such a world can exist both in the world and in the μετακόσμιον, as we call the space between the worlds, being a huge space made up of plenum and vacuum, but not, as some philosophers pretend, an immensity of space absolutely empty. This production of a world may be explained thus: seeds suitably appropriated to such an end may emanate either from one or from several worlds, or from the space that separates them; they flow towards a particular point where they become collected together and organized; after that, other germs come to unite them together in such a way as to form a durable whole, a basis, a nucleus to which all successive additions unite themselves.
One must not content oneself in this question with saying, as one of the natural philosophers has done, that there is a reunion of the elements, or a violent motion in the vacuum under the influence of necessity, and that the body which is thus produced increases until it comes to crash against some other; for this doctrine is contrary to appearances.
The sun, the moon, and the other stars were originally formed separately, and were afterwards comprehended in the entire total of the world. All the other objects which our world comprises, for instance the earth and the sea, were also formed spontaneously, and subsequently gained size by the addition and violent movement of light substances, composed of elements of fire and air, or even of these two principles at once. This explanation, moreover, is in accordance with the impressions of the senses.
As to the magnitude of the sun and of the other stars, it is as far as we are concerned, such as it appears to us to be.
This same doctrine is reproduced, and occurs again in the eleventh book of his treatise on Nature; where he says, “If the distance has made it lose its size, a fortiori, it would take away its brilliancy; for color has not, any more than size, the property of traversing distance without alteration.”
But considered by itself, the sun may be a little greater or a little smaller than it appears, or it may be just such as it looks, for that is exactly the case with the fires of common occurrence among men which are perceived by the senses at a distance. Besides, all the difficulties on this subject will be easily explained if one attends to the clear evidence of the perceptions, as I have shown in my books about Nature.
The rising and setting of the sun, of the moon, and of the stars, may depend on the fact of their becoming lighted up, and extinguished alternately, and in the order which we behold. One may also give other reasons for this phenomenon, which are not contradicted by any sensible appearances; accordingly, one might explain them by the passage of the stars above and below the earth, for the impressions of the senses agree also with this supposition.