Aristotle - On Youth and Old Age(1).pdf - Arystoteles - The9

350 BC

ON YOUTH AND OLD AGE, ON LIFE AND DEATH,

ON BREATHING

by Aristotle

translated by G. R. T. Ross

WE must now treat of youth and old age and life and death. We must

probably also at the same time state the causes of respiration as

well, since in some cases living and the reverse depend on this.

We have elsewhere given a precise account of the soul, and while

it is clear that its essential reality cannot be corporeal, yet

manifestly it must exist in some bodily part which must be one of

those possessing control over the members. Let us for the present

set aside the other divisions or faculties of the soul (whichever of

the two be the correct name). But as to being what is called an animal

and a living thing, we find that in all beings endowed with both

characteristics (viz. being an animal and being alive) there must be a

single identical part in virtue of which they live and are called

animals; for an animal qua animal cannot avoid being alive. But a

thing need not, though alive, be animal, for plants live without

having sensation, and it is by sensation that we distinguish animal

from what is not animal.

This organ, then, must be numerically one and the same and yet

possess multiple and disparate aspects, for being animal and living

are not identical. Since then the organs of special sensation have one

common organ in which the senses when functioning must meet, and

this must be situated midway between what is called before and

behind (we call 'before' the direction from which sensation comes,

'behind' the opposite), further, since in all living things the body

is divided into upper and lower (they all have upper and lower

parts, so that this is true of plants as well), clearly the

nutritive principle must be situated midway between these regions.

That part where food enters we call upper, considering it by itself

and not relatively to the surrounding universe, while downward is that

part by which the primary excrement is discharged.

Plants are the reverse of animals in this respect. To man in

particular among the animals, on account of his erect stature, belongs

the characteristic of having his upper parts pointing upwards in the

sense in which that applies to the universe, while in the others these

are in an intermediate position. But in plants, owing to their being

stationary and drawing their sustenance from the ground, the upper

part must always be down; for there is a correspondence between the

roots in a plant and what is called the mouth in animals, by means

of which they take in their food, whether the source of supply be

the earth or each other's bodies.

All perfectly formed animals are to be divided into three parts, one

that by which food is taken in, one that by which excrement is

discharged, and the third the region intermediate between them. In the

largest animals this latter is called the chest and in the others

something corresponding; in some also it is more distinctly marked off

than in others. All those also that are capable of progression have

additional members subservient to this purpose, by means of which they

bear the whole trunk, to wit legs and feet and whatever parts are

possessed of the same powers. Now it is evident both by observation

and by inference that the source of the nutritive soul is in the midst

of the three parts. For many animals, when either part-the head or the

receptacle of the food-is cut off, retain life in that member to which

the middle remains attached. This can be seen to occur in many

insects, e.g. wasps and bees, and many animals also besides insects

can, though divided, continue to live by means of the part connected

with nutrition.

While this member is indeed in actuality single, yet potentially

it is multiple, for these animals have a constitution similar to

that of Plants; plants when cut into sections continue to live, and

a number of trees can be derived from one single source. A separate

account will be given of the reason why some plants cannot live when

divided, while others can be propagated by the taking of slips. In

this respect, however, plants and insects are alike.

It is true that the nutritive soul, in beings possessing it, while

actually single must be potentially plural. And it is too with the

principle of sensation, for evidently the divided segments of these

animals have sensation. They are unable, however, to preserve their

constitution, as plants can, not possessing the organs on which the

continuance of life depends, for some lack the means for seizing,

others for receiving their food; or again they may be destitute of

other organs as well.

Divisible animals are like a number of animals grown together, but

animals of superior construction behave differently because their

constitution is a unity of the highest possible kind. Hence some of

the organs on division display slight sensitiveness because they

retain some psychical susceptibility; the animals continue to move

after the vitals have been abstracted: tortoises, for example, do so

even after the heart has been removed.

The same phenomenon is evident both in plants and in animals, and in

plants we note it both in their propagation by seed and in grafts

and cuttings. Genesis from seeds always starts from the middle. All

seeds are bivalvular, and the place of junction is situated at the

point of attachment (to the plant), an intermediate part belonging

to both halves. It is from this part that both root and stem of

growing things emerge; the starting-point is in a central position

between them. In the case of grafts and cuttings this is

particularly true of the buds; for the bud is in a way the

starting-point of the branch, but at the same time it is in a

central position. Hence it is either this that is cut off, or into

this that the new shoot is inserted, when we wish either a new

branch or a new root to spring from it; which proves that the point of

origin in growth is intermediate between stem and root.

Likewise in sanguineous animals the heart is the first organ

developed; this is evident from what has been observed in those

cases where observation of their growth is possible. Hence in

bloodless animals also what corresponds to the heart must develop

first. We have already asserted in our treatise on The Parts of

Animals that it is from the heart that the veins issue, and that in

sanguineous animals the blood is the final nutriment from which the

members are formed. Hence it is clear that there is one function in

nutrition which the mouth has the faculty of performing, and a

different one appertaining to the stomach. But it is the heart that

has supreme control, exercising an additional and completing function.

Hence in sanguineous animals the source both of the sensitive and of

the nutritive soul must be in the heart, for the functions relative to

nutrition exercised by the other parts are ancillary to the activity

of the heart. It is the part of the dominating organ to achieve the

final result, as of the physician's efforts to be directed towards

health, and not to be occupied with subordinate offices.

Certainly, however, all saguineous animals have the supreme organ of

the sensefaculties in the heart, for it is here that we must look

for the common sensorium belonging to all the sense-organs. These in

two cases, taste and touch, can be clearly seen to extend to the

heart, and hence the others also must lead to it, for in it the

other organs may possibly initiate changes, whereas with the upper

region of the body taste and touch have no connexion. Apart from these

considerations, if the life is always located in this part,

evidently the principle of sensation must be situated there too, for

it is qua animal that an animal is said to be a living thing, and it

is called animal because endowed with sensation. Elsewhere in other

works we have stated the reasons why some of the sense-organs are,

as is evident, connected with the heart, while others are situated

in the head. (It is this fact that causes some people to think that it

is in virtue of the brain that the function of perception belongs to

animals.)

Thus if, on the one hand, we look to the observed facts, what we

have said makes it clear that the source of the sensitive soul,

together with that connected with growth and nutrition, is situated in

this organ and in the central one of the three divisions of the

body. But it follows by deduction also; for we see that in every case,

when several results are open to her, Nature always brings to pass the

best. Now if both principles are located in the midst of the

substance, the two parts of the body, viz. that which elaborates and

that which receives the nutriment in its final form will best

perform their appropriate function; for the soul will then be close to

each, and the central situation which it will, as such, occupy is

the position of a dominating power.

Further, that which employs an instrument and the instrument it

employs must be distinct (and must be spatially diverse too, if

possible, as in capacity), just as the flute and that which plays

it-the hand-are diverse. Thus if animal is defined by the possession

of sensitive soul, this soul must in the sanguineous animals be in the

heart, and, in the bloodless ones, in the corresponding part of

their body. But in animals all the members and the whole body

possess some connate warmth of constitution, and hence when alive they

are observed to be warm, but when dead and deprived of life they are

the opposite. Indeed, the source of this warmth must be in the heart

in sanguineous animals, and in the case of bloodless animals in the

corresponding organ, for, though all parts of the body by means of

their natural heat elaborate and concoct the nutriment, the

governing organ takes the chief share in this process. Hence, though

the other members become cold, life remains; but when the warmth

here is quenched, death always ensues, because the source of heat in

all the other members depends on this, and the soul is, as it were,

set aglow with fire in this part, which in sanguineous animals is

the heart and in the bloodless order the analogous member. Hence, of

necessity, life must be coincident with the maintenance of heat, and

what we call death is its destruction.

However, it is to be noticed that there are two ways in which fire

ceases to exist; it may go out either by exhaustion or by

extinction. That which is self-caused we call exhaustion, that due

to its opposites extinction. [The former is that due to old age, the

latter to violence.] But either of these ways in which fire ceases

to be may be brought about by the same cause, for, when there is a

deficiency of nutriment and the warmth can obtain no maintenance,

the fire fails; and the reason is that the opposite, checking

digestion, prevents the fire from being fed. But in other cases the

result is exhaustion,-when the heat accumulates excessively owing to

lack of respiration and of refrigeration. For in this case what

happens is that the heat, accumulating in great quantity, quickly uses

up its nutriment and consumes it all before more is sent up by

evaporation. Hence not only is a smaller fire readily put out by a

large one, but of itself the candle flame is consumed when inserted in

a large blaze just as is the case with any other combustible. The

reason is that the nutriment in the flame is seized by the larger

one before fresh fuel can be added, for fire is ever coming into being

and rushing just like a river, but so speedily as to elude

observation.

Clearly therefore, if the bodily heat must be conserved (as is

necessary if life is to continue), there must be some way of cooling

the heat resident in the source of warmth. Take as an illustration

Aristotle - On Youth and Old Age(1).pdf

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