Timaeus
the sharpness of the angles, and the smallness of the particles,
and the swiftness of the motion—all this makes the action of fire
violent and sharp, so that it cuts whatever it meets. And we must
not forget that the original figure of fire (i.e. the pyramid),
more than any other form, has a dividing power which cuts our
bodies into small pieces (Kepmatizei), and thus naturally
produces that affection which we call heat; and hence the origin
of the name (thepmos, Kepma). Now, the opposite of this is
sufficiently manifest; nevertheless we will not fail to describe
it. For the larger particles of moisture which surround the body,
entering in and driving out the lesser, but not being able to
take their places, compress the moist principle in us; and this
from being unequal and disturbed, is forced by them into a state
of rest, which is due to equability and compression. But things
which are contracted contrary to nature are by nature at war, and
force themselves apart; and to this war and convulsion the name
of shivering and trembling is given; and the whole affection and
the cause of the affection are both termed cold. That is called
hard to which our flesh yields, and soft which yields to our
flesh; and things are also termed hard and soft relatively to one
another. That which yields has a small base; but that which rests
on quadrangular bases is firmly posed and belongs to the class
which offers the greatest resistance; so too does that which is
the most compact and therefore most repellent. The nature of the
light and the heavy will be best understood when examined in
connexion with our notions of above and below; for it is quite a
mistake to suppose that the universe is parted into two regions,
separate from and opposite to each other, the one a lower to
which all things tend which have any bulk, and an upper to which
things only ascend against their will. For as the universe is in
the form of a sphere, all the extremities, being equidistant from
the centre, are equally extremities, and the centre, which is
equidistant from them, is equally to be regarded as the opposite
of them all. Such being the nature of the world, when a person
says that any of these points is above or below, may he not be
justly charged with using an improper expression? For the centre
of the world cannot be rightly called either above or below, but
is the centre and nothing else; and the circumference is not the
centre, and has in no one part of itself a different relation to
the centre from what it has in any of the opposite parts. Indeed,
when it is in every direction similar, how can one rightly give
to it names which imply opposition? For if there were any solid
body in equipoise at the centre of the universe, there would be
nothing to draw it to this extreme rather than to that, for they
are all perfectly similar; and if a person were to go round the
world in a circle, he would often, when standing at the antipodes
of his former position, speak of the same point as above and
below; for, as I was saying just now, to speak of the whole which
is in the form of a globe as having one part above and another
below is not like a sensible man. The reason why these names are
used, and the circumstances under which they are ordinarily
applied by us to the division of the heavens, may be elucidated
by the following supposition:—if a person were to stand in that
part of the universe which is the appointed place of fire, and
where there is the great mass of fire to which fiery bodies
gather—if, I say, he were to ascend thither, and, having the
power to do this, were to abstract particles of fire and put them
in scales and weigh them, and then, raising the balance, were to
draw the fire by force towards the uncongenial element of the
air, it would be very evident that he could compel the smaller
mass more readily than the larger; for when two things are
simultaneously raised by one and the same power, the smaller body
must necessarily yield to the superior power with less reluctance
than the larger; and the larger body is called heavy and said to
tend downwards, and the smaller body is called light and said to
tend upwards. And we may detect ourselves who are upon the earth
doing precisely the same thing. For we often separate earthy
natures, and sometimes earth itself, and draw them into the
uncongenial element of air by force and contrary to nature, both
clinging to their kindred elements. But that which is smaller
yields to the impulse given by us towards the dissimilar element
more easily than the larger; and so we call the former light, and
the place towards which it is impelled we call above, and the
contrary state and place we call heavy and below respectively.
Now the relations of these must necessarily vary, because the
principal masses of the different elements hold opposite
positions; for that which is light, heavy, below or above in one
place will be found to be and become contrary and transverse and
every way diverse in relation to that which is light, heavy,
below or above in an opposite place. And about all of them this
has to be considered:—that the tendency of each towards its
kindred element makes the body which is moved heavy, and the
place towards which the motion tends below, but things which have
an opposite tendency we call by an opposite name. Such are the
causes which we assign to these phenomena. As to the smooth and
the rough, any one who sees them can explain the reason of them
to another. For roughness is hardness mingled with irregularity,
and smoothness is produced by the joint effect of uniformity and
density.
The most important of the affections which concern the whole body
remains to be considered—that is, the cause of pleasure and pain
in the perceptions of which I have been speaking, and in all
other things which are perceived by sense through the parts of
the body, and have both pains and pleasures attendant on them.
Let us imagine the causes of every affection, whether of sense or
not, to be of the following nature, remembering that we have
already distinguished between the nature which is easy and which
is hard to move; for this is the direction in which we must hunt
the prey which we mean to take. A body which is of a nature to be
easily moved, on receiving an impression however slight, spreads
abroad the motion in a circle, the parts communicating with each
other, until at last, reaching the principle of mind, they
announce the quality of the agent. But a body of the opposite
kind, being immobile, and not extending to the surrounding
region, merely receives the impression, and does not stir any of
the neighbouring parts; and since the parts do not distribute the
original impression to other parts, it has no effect of motion on
the whole animal, and therefore produces no effect on the
patient. This is true of the bones and hair and other more earthy
parts of the human body; whereas what was said above relates
mainly to sight and hearing, because they have in them the
greatest amount of fire and air. Now we must conceive of pleasure
and pain in this way. An impression produced in us contrary to
nature and violent, if sudden, is painful; and, again, the sudden
return to nature is pleasant; but a gentle and gradual return is
imperceptible and vice versa. On the other hand the impression of
sense which is most easily produced is most readily felt, but is
not accompanied by pleasure or pain; such, for example, are the
affections of the sight, which, as we said above, is a body
naturally uniting with our body in the day-time; for cuttings and
burnings and other affections which happen to the sight do not
give pain, nor is there pleasure when the sight returns to its
natural state; but the sensations are clearest and strongest
according to the manner in which the eye is affected by the
object, and itself strikes and touches it; there is no violence
either in the contraction or dilation of the eye. But bodies
formed of larger particles yield to the agent only with a
struggle; and then they impart their motions to the whole and
cause pleasure and pain—pain when alienated from their natural
conditions, and pleasure when restored to them. Things which
experience gradual withdrawings and emptyings of their nature,
and great and sudden replenishments, fail to perceive the
emptying, but are sensible of the replenishment; and so they
occasion no pain, but the greatest pleasure, to the mortal part
of the soul, as is manifest in the case of perfumes. But things
which are changed all of a sudden, and only gradually and with
difficulty return to their own nature, have effects in every way
opposite to the former, as is evident in the case of burnings and
cuttings of the body.
Thus have we discussed the general affections of the whole body,
and the names of the agents which produce them. And now I will
endeavour to speak of the affections of particular parts, and the
causes and agents of them, as far as I am able. In the first
place let us set forth what was omitted when we were speaking of
juices, concerning the affections peculiar to the tongue. These
too, like most of the other affections, appear to be caused by
certain contractions and dilations, but they have besides more of
roughness and smoothness than is found in other affections; for
whenever earthy particles enter into the small veins which are
the testing instruments of the tongue, reaching to the heart, and
fall upon the moist, delicate portions of flesh—when, as they are
dissolved, they contract and dry up the little veins, they are
astringent if they are rougher, but if not so rough, then only
harsh. Those of them which are of an abstergent nature, and purge
the whole surface of the tongue, if they do it in excess, and so
encroach as to consume some part of the flesh itself, like potash
and soda, are all termed bitter. But the particles which are
deficient in the alkaline quality, and which cleanse only
moderately, are called salt, and having no bitterness or
roughness, are regarded as rather agreeable than otherwise.
Bodies which share in and are made smooth by the heat of the
mouth, and which are inflamed, and again in turn inflame that
which heats them, and which are so light that they are carried
upwards to the sensations of the head, and cut all that comes in
their way, by reason of these qualities in them, are all termed
pungent. But when these same particles, refined by putrefaction,
enter into the narrow veins, and are duly proportioned to the
particles of earth and air which are there, they set them
whirling about one another, and while they are in a whirl cause
them to dash against and enter into one another, and so form
hollows surrounding the particles that enter—which watery vessels