The Lives and Opinions of Eminent Philosophers by Diogenes Laërtius (best free ebook reader txt) 📕

for a man to explain, and what is inaccessible to his intelligence; one does not throw oneself into interminable speculations.

It may also be possibly the case that the moon has a light of her own, or that she reflects that of the sun. For we see around us many objects which are luminous of themselves, and many others which have only a borrowed light. In a word, one will not be arrested by any of the celestial phenomena, provided that one always recollects that there are many explanations possible; that one examines the principles and reasons which agree with this mode of explanation, and that one does not proceed in accounting for the facts which do not agree with this method, to suffer oneself to be foolishly carried away, and to propose a separate explanation for each phenomenon, sometimes in one way, and sometimes in another.

The appearance of a face in the orb of the moon may depend either on a displacement of its parts, or on the interposition of some obstacle, or on any other cause capable of accounting for such an appearance. For one must not neglect to apply this same method to all the heavenly phenomena; for, from the moment when one comes to any point of contradiction to the evidence of the senses, it will be impossible to possess perfect tranquillity and happiness.

The eclipses of the sun and moon may depend either on the fact that these stars extinguish themselves, a phenomenon which we often see produced under our eyes, or on the fact of other bodies, the earth, the heaven, or something else of the same kind interposing between them and us. Besides, we must compare the different modes of explanation appropriate to phenomena, and recollect that it is not impossible that many causes may at one and the same time concur in their production.

He says the same thing in the twelfth book of his treatise on Nature; and adds that the eclipses of the sun arise from the fact that it penetrates into the shade of the moon, to quit it again presently; and the eclipses of the moon from the fact of its entering into the shade of the earth. We also find the same doctrine asserted by Diogenes, the Epicurean, in the first book of his Select Opinions.

The regular and periodical march of these phenomena has nothing in it that ought to surprise us, if we only attend to the analogous facts which take place under our eyes. Above all things let us beware of making the Deity interpose here, for that being we ought to suppose exempt from all occupation and perfectly happy; otherwise we shall be only giving vain explanations of the heavenly phenomena, as has happened already to a crowd of authors. Not being able to recognize what is really possible, they have fallen into vain theories, in supposing that for all phenomena there was but one single mode of production, and in rejecting all other explanations which are founded on probability; they have adopted the most unreasonable opinions, for want of placing in the front the study of the heavenly phenomena, and of sensible facts, which ought to serve to explain the first.

The differences in the length of nights and days may arise from the fact that the passage of the sun above the earth is more or less rapid; and more or less slow, according to the length of the regions which it has to pass through. Or, again, to the fact that certain regions are passed through more rapidly than others, as is seen to be the case by our own eyes, in those things to which we can compare the heavenly phenomena. As to those who on this point admit only one explanation as possible, they put themselves in opposition to facts, and lose sight of the bounds set to human knowledge.

The prognostics which are derived from the stars may, like those which we borrow from animals, arise from a simple coincidence. They may also have other causes, for example, some change in the air; for these two suppositions both harmonize equally with facts, but it is impossible to distinguish in what case one is to attribute them to the one cause or to the other.

The clouds may be formed either by the air condensed under the pressure of the winds, or by the agency of atoms set apart for that end, or by emanations from the earth and waters, or by other causes. For there are a great number which are all equally able to produce this effect. When the clouds clash with one another, or undergo any transformation, they produce showers; and the long rains are caused by the motion of the clouds when moved from places suitable to them through the air, when a more violent inundation than usual takes place, from collections of some masses calculated to produce these effects.

Thunder possibly arises from the movement of the winds revolving in the cavities of the clouds; of which we may see an image in vessels in our own daily use. It may also arise from the noise of fire acted upon by the wind in them, and from the tearings and ruptures of the clouds when they have received a sort of crystaline consistency. In a word, experience drawn from our senses teaches us that all these phenomena, and that one in particular, may be produced in many different manners.

One may also assign different causes to the lightning; either the shock and collision of the clouds produce a fiery appearance, which is followed by lightning; or the lighting up of the clouds by the winds, produces this luminous appearance; or the mutual pressure of the clouds, or that of the wind against them, disengages the lightning. Or one might say that the interception of the light diffused from the stars, arrested for a time in the bosom of the clouds, is driven from them subsequently by their own movements, and