The Lives and Opinions of Eminent Philosophers
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 phænomena, 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 endeavour 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 phænomena:
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, _à 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 phænomena 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 one’s self altogether at a
distance from the science of nature, in order to fall into fables.
“It is possible that the heavenly phænomena may present some apparent
characters which appear to assimilate them to those phænomena which we
see taking place around ourselves, without there being any real analogy
at the bottom. For the heavenly phænomena 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 phænomena 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 one’s self in this question with saying, as one
of the natural philosophers has done, that there is a re-union 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, _à fortiori_, it would take away its brilliancy; for
colour 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 phænomenon, 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.
“As to their motion, one may make that depend on the circular movement
of the entire heaven. One may also suppose that the stars move, while
the heaven itself is immoveable; for there is nothing to prevent the
idea that originally, before the formation of the world, they may have
received, by the appointment of fate, an impulse from east to west, and
that now their movement continues in consequence of their heat, as the
fire naturally proceeds onwards in order to seek the aliment which suits
it.
“The intertropical movements of the sun and moon may depend, either on
the obliquity impressed by fate on the heaven at certain determined
epochs, or on the resistance of the air, or on the fact that these
ignited bodies stand in need of being nourished by a matter suitable
to their nature, and that this matter fails them; or finally, they
may depend on the fact of their having originally received an impulse
which compels them to move as they do describing a sort of spiral
figure. The sensible evidence does not in the least contradict these
different suppositions, and all those of the same kind which one can
form, having always a due regard to what is possible, and bringing
back each phænomenon to its analogous appearances in sensible facts,
without disquieting one’s self about the miserable speculations of the
astronomers.
“The evacuations and subsequent replenishings of the moon may depend
either on a conversion of this body, or on the different forms which the
air when in a fiery state can adopt, or perhaps to the interposition of
another body, or lastly, to some one of the causes by which one gives
account of the analogous phænomena which pass under our eyes. Provided,
however, that one does not obstinately adopt an exclusive mode of
explanation; and that, for want of knowing what is possible for a man to
explain, and what is inaccessible to his intelligence; one does not throw
one’s self 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 phænomena, 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 one’s self to be foolishly carried away, and to propose a separate
explanation for each phænomenon, 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 phænomena;
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 phænomenon 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 phænomena, 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 phænomena 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 phænomena, 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 phænomena
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 phænomena, 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 phænomena. As
to those who on this point admit only one explanation as possible, they