Longevity and Shortness of Life E-book

                                350 BC

                  ON LONGEVITY AND SHORTNESS OF LIFE

                             by Aristotle

                     translated by G. R. T. Ross






Electronically Enhanced Text (c) Copyright 1996, World Library(R)



                              CHAPTER 1
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  THE reasons for some animals being long-lived and others
short-lived, and, in a word, causes of the length and brevity of life
call for investigation.
  The necessary beginning to our inquiry is a statement of the
difficulties about these points. For it is not clear whether in
animals and plants universally it is a single or diverse cause that
makes some to be long-lived, others short-lived. Plants too have in
some cases a long life, while in others it lasts but for a year.
  Further, in a natural structure are longevity and a sound
constitution coincident, or is shortness of life independent of
unhealthiness? Perhaps in the case of certain maladies a diseased
state of the body and shortness of life are interchangeable, while in
the case of others ill-health is perfectly compatible with long life.
  Of sleep and waking we have already treated; about life and death we
shall speak later on, and likewise about health and disease, in so far
as it belongs to the science of nature to do so. But at present we
have to investigate the causes of some creatures being long-lived, and
others short-lived. We find this distinction affecting not only entire
genera opposed as wholes to one another, but applying also to
contrasted sets of individuals within the same species. As an instance
of the difference applying to the genus I give man and horse (for
mankind has a longer life than the horse), while within the species
there is the difference between man and man; for of men also some are
long-lived, others short-lived, differing from each other in respect
of the different regions in which they dwell. Races inhabiting warm
countries have longer life, those living in a cold climate live a
shorter time. Likewise there are similar differences among individuals
occupying the same locality.


                              CHAPTER 2
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  In order to find premisses for our argument, we must answer the
question, What is that which, in natural objects, makes them easily
destroyed, or the reverse? Since fire and water, and whatsoever is
akin thereto, do not possess identical powers they are reciprocal
causes of generation and decay. Hence it is natural to infer that
everything else arising from them and composed of them should share in
the same nature, in all cases where things are not, like a house, a
composite unity formed by the synthesis of many things.
  In other matters a different account must be given; for in many
things their mode of dissolution is something peculiar to themselves,
e.g. in knowledge and health and disease. These pass away even though
the medium in which they are found is not destroyed but continues to
exist; for example, take the termination of ignorance, which is
recollection or learning, while knowledge passes away into
forgetfulness, or error. But accidentally the disintegration of a
natural object is accompanied by the destruction of the non-physical
reality; for, when the animal dies, the health or knowledge resident
in it passes away too. Hence from these considerations we may draw a
conclusion about the soul too; for, if the inherence of soul in body
is not a matter of nature but like that of knowledge in the soul,
there would be another mode of dissolution pertaining to it besides
that which occurs when the body is destroyed. But since evidently it
does not admit of this dual dissolution, the soul must stand in a
different case in respect of its union with the body.


                              CHAPTER 3
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  Perhaps one might reasonably raise the question whether there is any
place where what is corruptible becomes incorruptible, as fire does in
the upper regions where it meets with no opposite. Opposites destroy
each other, and hence accidentally, by their destruction, whatsoever
is attributed to them is destroyed. But no opposite in a real
substance is accidentally destroyed, because real substance is not
predicated of any subject. Hence a thing which has no opposite, or
which is situated where it has no opposite, cannot be destroyed. For
what will that be which can destroy it, if destruction comes only
through contraries, but no contrary to it exists either absolutely or
in the particular place where it is? But perhaps this is in one sense
true, in another sense not true, for it is impossible that anything
containing matter should not have in any sense an opposite. Heat and
straightness can be present in every part of a thing, but it is
impossible that the thing should be nothing but hot or white or
straight; for, if that were so, attributes would have an independent
existence. Hence if, in all cases, whenever the active and the passive
exist together, the one acts and the other is acted on, it is
impossible that no change should occur. Further, this is so if a waste
product is an opposite, and waste must always be produced; for
opposition is always the source of change, and refuse is what
remains of the previous opposite. But, after expelling everything of a
nature actually opposed, would an object in this case also be
imperishable? No, it would be destroyed by the environment.
  If then that is so, what we have said sufficiently accounts for the
change; but, if not, we must assume that something of actually
opposite character is in the changing object, and refuse is produced.
  Hence accidentally a lesser flame is consumed by a greater one, for
the nutriment, to wit the smoke, which the former takes a long period
to expend, is used up by the big flame quickly.
  Hence [too] all things are at all times in a state of transition and
are coming into being and passing away. The environment acts on them
either favourably or antagonistically, and, owing to this, things that
change their situation become more or less enduring than their nature
warrants, but never are they eternal when they contain contrary
qualities; for their matter is an immediate source of contrariety, so
that if it involves locality they show change of situation, if
quantity, increase and diminution, while if it involves qualitative
affection we find alteration of character.


                              CHAPTER 4
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  We find that a superior immunity from decay attaches neither to the
largest animals (the horse has shorter life than man) nor to those
that are small (for most insects live but for a year). Nor are plants
as a whole less liable to perish than animals (many plants are
annuals), nor have sanguineous animals the pre-eminence (for the bee
is longer-lived than certain sanguineous animals). Neither is it the
bloodless animals that live longest (for molluscs live only a year,
though bloodless), nor terrestrial organisms (there are both plants
and terrestrial animals of which a single year is the period), nor the
occupants of the sea (for there we find the crustaceans and the
molluscs, which are short-lived).
  Speaking generally, the longest-lived things occur among the plants,
e.g. the date-palm. Next in order we find them among the sanguineous
animals rather than among the bloodless, and among those with feet
rather than among the denizens of the water. Hence, taking these two
characters together, the longest-lived animals fall among sanguineous
animals which have feet, e.g. man and elephant. As a matter of fact
also it is a general rule that the larger live longer than the
smaller, for the other long-lived animals too happen to be of a large
size, as are also those I have mentioned.


                              CHAPTER 5
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  The following considerations may enable us to understand the reasons
for all these facts. We must remember that an animal is by nature
humid and warm, and to live is to be of such a constitution, while old
age is dry and cold, and so is a corpse. This is plain to observation.
But the material constituting the bodies of all things consists of the
following- the hot and the cold, the dry and the moist. Hence when
they age they must become dry, and therefore the fluid in them
requires to be not easily dried up. Thus we explain why fat things are
not liable to decay. The reason is that they contain air; now air
relatively to the other elements is fire, and fire never becomes
corrupted.
  Again the humid element in animals must not be small in quantity,
for a small quantity is easily dried up. This is why both plants and
animals that are large are, as a general rule, longer-lived than the
rest, as was said before; it is to be expected that the larger should
contain more moisture. But it is not merely this that makes them
longer lived; for the cause is twofold, to wit, the quality as well as
the quantity of the fluid. Hence the moisture must be not only great
in amount but also warm, in order to be neither easily congealed nor
easily dried up.
  It is for this reason also that man lives longer than some animals
which are larger; for animals live longer though there is a deficiency
in the amount of their moisture, if the ratio of its qualitative
superiority exceeds that of its quantitative deficiency.
  In some creatures the warm element is their fatty substance, which
prevents at once desiccation and congelation; but in others it assumes
a different flavour. Further, that which is designed to be not easily
destroyed should not yield waste products. Anything of such a nature
causes death either by disease or naturally, for the potency of the
waste product works adversely and destroys now the entire
constitution, now a particular member.
  This is why salacious animals and those abounding in seed age
quickly; the seed is a residue, and further, by being lost, it
produces dryness. Hence the mule lives longer than either the horse or
the ass from which it sprang, and females live longer than males if
the males are salacious. Accordingly cock-sparrows have a shorter life
than the females. Again males subject to great toil are short-lived
and age more quickly owing to the labour; toil produces dryness and
old age is dry. But by natural constitution and as a general rule
males live longer than females, and the reason is that the male is an
animal with more warmth than the female.
                                                         
  The same kind of animals are longer-lived in warm than in cold
climates for the same reason, on account of which they are of larger
size. The size of animals of cold constitution illustrates this
particularly well, and hence snakes and lizards and scaly reptiles are
of great size in warm localities, as also are testacea in the Red Sea:
the warm humidity there is the cause equally of their augmented size
and of their life. But in cold countries the humidity in animals is
more of a watery nature, and hence is readily congealed. Consequently
it happens that animals with little or no blood are in northerly
regions either entirely absent (both the land animals with feet and
the water creatures whose home is the sea) or, when they do occur,
they are smaller and have shorter life; for the frost prevents growth.
  Both plants and animals perish if not fed, for in that case they
consume themselves; just as a large flame consumes and burns up a
small one by using up its nutriment, so the natural warmth which is
the primary cause of digestion consumes the material in which it is
located.
  Water animals have a shorter life than terrestrial creatures, not
strictly because they are humid, but because they are watery, and
watery moisture is easily destroyed, since it is cold and readily
congealed. For the same reason bloodless animals perish readily unless
protected by great size, for there is neither fatness nor sweetness
about them. In animals fat is sweet, and hence bees are longer-lived
than other animals of larger size.


                              CHAPTER 6
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  It is amongst the plants that we find the longest life- more than
among the animals, for, in the first place, they are less watery and
hence less easily frozen. Further they have an oiliness and a
viscosity which makes them retain their moisture in a form not easily
dried up, even though they are dry and earthy.
  But we must discover the reason why trees are of an enduring
constitution, for it is peculiar to them and is not found in any
animals except the insects.
  Plants continually renew themselves and hence last for a long time.
New shoots continually come and the others grow old, and with the
roots the same thing happens. But both processes do not occur
together. Rather it happens that at one time the trunk and the
branches alone die and new ones grow up beside them, and it is only
when this has taken place that the fresh roots spring from the
surviving part. Thus it continues, one part dying and the other
growing, and hence also it lives a long time.
  There is a similarity, as has been already said, between plants and
insects, for they live, though divided, and two or more may be derived
from a single one. Insects, however, though managing to live, are not
able to do so long, for they do not possess organs; nor can the
principle resident in each of the separated parts create organs. In
the case of a plant, however, it can do so; every part of a plant
contains potentially both root and stem. Hence it is from this source
that issues that continued growth when one part is renewed and the
other grows old; it is practically a case of longevity. The taking of
slips furnishes a similar instance, for we might say that, in a way,
when we take a slip the same thing happens; the shoot cut off is part
of the plant. Thus in taking slips this perpetuation of life occurs
though their connexion with the plant is severed, but in the former
case it is the continuity that is operative. The reason is that the
life principle potentially belonging to them is present in every part.
  Identical phenomena are found both in plants and in animals. For
in animals the males are, in general, the longer-lived. They have
their upper parts larger than the lower (the male is more of the dwarf
type of build than the female), and it is in the upper part that
warmth resides, in the lower cold. In plants also those with great
heads are longer-lived, and such are those that are not annual but of
the tree-type, for the roots are the head and upper part of a plant,
and among the annuals growth occurs in the direction of their lower
parts and the fruit.
                                                         
  These matters however will be specially investigated in the work
On Plants. But this is our account of the reasons for the duration
of life and for short life in animals. It remains for us to discuss
youth and age, and life and death. To come to a definite understanding
about these matters would complete our course of study on animals.
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                               THE END