Timaeus
inequality is the cause of the nature which is wanting in
uniformity; and of this we have already described the origin. But
there still remains the further point—why things when divided
after their kinds do not cease to pass through one another and to
change their place—which we will now proceed to explain. In the
revolution of the universe are comprehended all the four
elements, and this being circular and having a tendency to come
together, compresses everything and will not allow any place to
be left void. Wherefore, also, fire above all things penetrates
everywhere, and air next, as being next in rarity of the
elements; and the two other elements in like manner penetrate
according to their degrees of rarity. For those things which are
composed of the largest particles have the largest void left in
their compositions, and those which are composed of the smallest
particles have the least. And the contraction caused by the
compression thrusts the smaller particles into the interstices of
the larger. And thus, when the small parts are placed side by
side with the larger, and the lesser divide the greater and the
greater unite the lesser, all the elements are borne up and down
and hither and thither towards their own places; for the change
in the size of each changes its position in space. And these
causes generate an inequality which is always maintained, and is
continually creating a perpetual motion of the elements in all
time.
In the next place we have to consider that there are divers kinds
of fire. There are, for example, first, flame; and secondly,
those emanations of flame which do not burn but only give light
to the eyes; thirdly, the remains of fire, which are seen in
red-hot embers after the flame has been extinguished. There are
similar differences in the air; of which the brightest part is
called the aether, and the most turbid sort mist and darkness;
and there are various other nameless kinds which arise from the
inequality of the triangles. Water, again, admits in the first
place of a division into two kinds; the one liquid and the other
fusile. The liquid kind is composed of the small and unequal
particles of water; and moves itself and is moved by other bodies
owing to the want of uniformity and the shape of its particles;
whereas the fusile kind, being formed of large and uniform
particles, is more stable than the other, and is heavy and
compact by reason of its uniformity. But when fire gets in and
dissolves the particles and destroys the uniformity, it has
greater mobility, and becoming fluid is thrust forth by the
neighbouring air and spreads upon the earth; and this dissolution
of the solid masses is called melting, and their spreading out
upon the earth flowing. Again, when the fire goes out of the
fusile substance, it does not pass into a vacuum, but into the
neighbouring air; and the air which is displaced forces together
the liquid and still moveable mass into the place which was
occupied by the fire, and unites it with itself. Thus compressed
the mass resumes its equability, and is again at unity with
itself, because the fire which was the author of the inequality
has retreated; and this departure of the fire is called cooling,
and the coming together which follows upon it is termed
congealment. Of all the kinds termed fusile, that which is the
densest and is formed out of the finest and most uniform parts is
that most precious possession called gold, which is hardened by
filtration through rock; this is unique in kind, and has both a
glittering and a yellow colour. A shoot of gold, which is so
dense as to be very hard, and takes a black colour, is termed
adamant. There is also another kind which has parts nearly like
gold, and of which there are several species; it is denser than
gold, and it contains a small and fine portion of earth, and is
therefore harder, yet also lighter because of the great
interstices which it has within itself; and this substance, which
is one of the bright and denser kinds of water, when solidified
is called copper. There is an alloy of earth mingled with it,
which, when the two parts grow old and are disunited, shows
itself separately and is called rust. The remaining phenomena of
the same kind there will be no difficulty in reasoning out by the
method of probabilities. A man may sometimes set aside
meditations about eternal things, and for recreation turn to
consider the truths of generation which are probable only; he
will thus gain a pleasure not to be repented of, and secure for
himself while he lives a wise and moderate pastime. Let us grant
ourselves this indulgence, and go through the probabilities
relating to the same subjects which follow next in order.
Water which is mingled with fire, so much as is fine and liquid
(being so called by reason of its motion and the way in which it
rolls along the ground), and soft, because its bases give way and
are less stable than those of earth, when separated from fire and
air and isolated, becomes more uniform, and by their retirement
is compressed into itself; and if the condensation be very great,
the water above the earth becomes hail, but on the earth, ice;
and that which is congealed in a less degree and is only half
solid, when above the earth is called snow, and when upon the
earth, and condensed from dew, hoar-frost. Then, again, there are
the numerous kinds of water which have been mingled with one
another, and are distilled through plants which grow in the
earth; and this whole class is called by the name of juices or
saps. The unequal admixture of these fluids creates a variety of
species; most of them are nameless, but four which are of a fiery
nature are clearly distinguished and have names. First, there is
wine, which warms the soul as well as the body: secondly, there
is the oily nature, which is smooth and divides the visual ray,
and for this reason is bright and shining and of a glistening
appearance, including pitch, the juice of the castor berry, oil
itself, and other things of a like kind: thirdly, there is the
class of substances which expand the contracted parts of the
mouth, until they return to their natural state, and by reason of
this property create sweetness;—these are included under the
general name of honey: and, lastly, there is a frothy nature,
which differs from all juices, having a burning quality which
dissolves the flesh; it is called opos (a vegetable acid).
As to the kinds of earth, that which is filtered through water
passes into stone in the following manner:—The water which mixes
with the earth and is broken up in the process changes into air,
and taking this form mounts into its own place. But as there is
no surrounding vacuum it thrusts away the neighbouring air, and
this being rendered heavy, and, when it is displaced, having been
poured around the mass of earth, forcibly compresses it and
drives it into the vacant space whence the new air had come up;
and the earth when compressed by the air into an indissoluble
union with water becomes rock. The fairer sort is that which is
made up of equal and similar parts and is transparent; that which
has the opposite qualities is inferior. But when all the watery
part is suddenly drawn out by fire, a more brittle substance is
formed, to which we give the name of pottery. Sometimes also
moisture may remain, and the earth which has been fused by fire
becomes, when cool, a certain stone of a black colour. A like
separation of the water which had been copiously mingled with
them may occur in two substances composed of finer particles of
earth and of a briny nature; out of either of them a
half-solid-body is then formed, soluble in water—the one, soda,
which is used for purging away oil and earth, the other, salt,
which harmonizes so well in combinations pleasing to the palate,
and is, as the law testifies, a substance dear to the gods. The
compounds of earth and water are not soluble by water, but by
fire only, and for this reason:—Neither fire nor air melt masses
of earth; for their particles, being smaller than the interstices
in its structure, have plenty of room to move without forcing
their way, and so they leave the earth unmelted and undissolved;
but particles of water, which are larger, force a passage, and
dissolve and melt the earth. Wherefore earth when not
consolidated by force is dissolved by water only; when
consolidated, by nothing but fire; for this is the only body
which can find an entrance. The cohesion of water again, when
very strong, is dissolved by fire only—when weaker, then either
by air or fire—the former entering the interstices, and the
latter penetrating even the triangles. But nothing can dissolve
air, when strongly condensed, which does not reach the elements
or triangles; or if not strongly condensed, then only fire can
dissolve it. As to bodies composed of earth and water, while the
water occupies the vacant interstices of the earth in them which
are compressed by force, the particles of water which approach
them from without, finding no entrance, flow around the entire
mass and leave it undissolved; but the particles of fire,
entering into the interstices of the water, do to the water what
water does to earth and fire to air (The text seems to be
corrupt.), and are the sole causes of the compound body of earth
and water liquefying and becoming fluid. Now these bodies are of
two kinds; some of them, such as glass and the fusible sort of
stones, have less water than they have earth; on the other hand,
substances of the nature of wax and incense have more of water
entering into their composition.
I have thus shown the various classes of bodies as they are
diversified by their forms and combinations and changes into one
another, and now I must endeavour to set forth their affections
and the causes of them. In the first place, the bodies which I
have been describing are necessarily objects of sense. But we
have not yet considered the origin of flesh, or what belongs to
flesh, or of that part of the soul which is mortal. And these
things cannot be adequately explained without also explaining the
affections which are concerned with sensation, nor the latter
without the former: and yet to explain them together is hardly
possible; for which reason we must assume first one or the other
and afterwards examine the nature of our hypothesis. In order,
then, that the affections may follow regularly after the
elements, let us presuppose the existence of body and soul.
First, let us enquire what we mean by saying that fire is hot;
and about this we may reason from the dividing or cutting power
which it exercises on our bodies. We all of us feel that fire is
sharp; and we may further consider the fineness of the sides, and