No More Learning

One thing is like another only with reference to that in
virtue of which it is such and such; thus this forms the peculiar mark
of quality.

We must not be disturbed because it may be argued that, though
proposing to discuss the category of quality, we have included in it
many relative terms. We did say that habits and dispositions were
relative. In practically all such cases the genus is relative, the
individual not. Thus knowledge, as a genus, is explained by
reference to something else, for we mean a knowledge of something. But
particular branches of knowledge are not thus explained. The knowledge
of grammar is not relative to anything external, nor is the
knowledge of music, but these, if relative at all, are relative only
in virtue of their genera; thus grammar is said be the knowledge of
something, not the grammar of something; similarly music is the
knowledge of something, not the music of something.

Thus individual branches of knowledge are not relative. And it is
because we possess these individual branches of knowledge that we
are said to be such and such. It is these that we actually possess: we
are called experts because we possess knowledge in some particular
branch. Those particular branches, therefore, of knowledge, in
virtue of which we are sometimes said to be such and such, are
themselves qualities, and are not relative. Further, if anything
should happen to fall within both the category of quality and that
of relation, there would be nothing extraordinary in classing it under
both these heads.

9

Action and affection both admit of contraries and also of
variation of degree. Heating is the contrary of cooling, being
heated of being cooled, being glad of being vexed. Thus they admit
of contraries. They also admit of variation of degree: for it is
possible to heat in a greater or less degree; also to be heated in a
greater or less degree. Thus action and affection also admit of
variation of degree. So much, then, is stated with regard to these
categories.

We spoke, moreover, of the category of position when we were dealing
with that of relation, and stated that such terms derived their
names from those of the corresponding attitudes.

As for the rest, time, place, state, since they are easily
intelligible, I say no more about them than was said at the beginning,
that in the category of state are included such states as 'shod',
'armed', in that of place 'in the Lyceum' and so on, as was
explained before.

10

The proposed categories have, then, been adequately dealt with.

We must next explain the various senses in which the term 'opposite'
is used. Things are said to be opposed in four senses: (i) as
correlatives to one another, (ii) as contraries to one another,
(iii) as privatives to positives, (iv) as affirmatives to negatives.

Let me sketch my meaning in outline. An instance of the use of the
word 'opposite' with reference to correlatives is afforded by the
expressions 'double' and 'half'; with reference to contraries by 'bad'
and 'good'. Opposites in the sense of 'privatives' and 'positives'
are' blindness' and 'sight'; in the sense of affirmatives and
negatives, the propositions 'he sits', 'he does not sit'.

(i) Pairs of opposites which fall under the category of relation are
explained by a reference of the one to the other, the reference
being indicated by the preposition 'of' or by some other
preposition. Thus, double is a relative term, for that which is double
is explained as the double of something. Knowledge, again, is the
opposite of the thing known, in the same sense; and the thing known
also is explained by its relation to its opposite, knowledge. For
the thing known is explained as that which is known by something, that
is, by knowledge. Such things, then, as are opposite the one to the
other in the sense of being correlatives are explained by a
reference of the one to the other.

(ii) Pairs of opposites which are contraries are not in any way
interdependent, but are contrary the one to the other. The good is not
spoken of as the good of the had, but as the contrary of the bad,
nor is white spoken of as the white of the black, but as the
contrary of the black. These two types of opposition are therefore
distinct. Those contraries which are such that the subjects in which
they are naturally present, or of which they are predicated, must
necessarily contain either the one or the other of them, have no
intermediate, but those in the case of which no such necessity
obtains, always have an intermediate. Thus disease and health are
naturally present in the body of an animal, and it is necessary that
either the one or the other should be present in the body of an
animal. Odd and even, again, are predicated of number, and it is
necessary that the one or the other should be present in numbers.
Now there is no intermediate between the terms of either of these
two pairs. On the other hand, in those contraries with regard to which
no such necessity obtains, we find an intermediate. Blackness and
whiteness are naturally present in the body, but it is not necessary
that either the one or the other should be present in the body,
inasmuch as it is not true to say that everybody must be white or
black. Badness and goodness, again, are predicated of man, and of many
other things, but it is not necessary that either the one quality or
the other should be present in that of which they are predicated: it
is not true to say that everything that may be good or bad must be
either good or bad. These pairs of contraries have intermediates:
the intermediates between white and black are grey, sallow, and all
the other colours that come between; the intermediate between good and
bad is that which is neither the one nor the other.

Some intermediate qualities have names, such as grey and sallow
and all the other colours that come between white and black; in
other cases, however, it is not easy to name the intermediate, but
we must define it as that which is not either extreme, as in the
case of that which is neither good nor bad, neither just nor unjust.

(iii) 'privatives' and 'Positives' have reference to the same
subject. Thus, sight and blindness have reference to the eye. It is
a universal rule that each of a pair of opposites of this type has
reference to that to which the particular 'positive' is natural. We
say that that is capable of some particular faculty or possession
has suffered privation when the faculty or possession in question is
in no way present in that in which, and at the time at which, it
should naturally be present. We do not call that toothless which has
not teeth, or that blind which has not sight, but rather that which
has not teeth or sight at the time when by nature it should. For there
are some creatures which from birth are without sight, or without
teeth, but these are not called toothless or blind.

To be without some faculty or to possess it is not the same as the
corresponding 'privative' or 'positive'. 'Sight' is a 'positive',
'blindness' a 'privative', but 'to possess sight' is not equivalent to
'sight', 'to be blind' is not equivalent to 'blindness'. Blindness
is a 'privative', to be blind is to be in a state of privation, but is
not a 'privative'. Moreover, if 'blindness' were equivalent to
'being blind', both would be predicated of the same subject; but
though a man is said to be blind, he is by no means said to be
blindness.

To be in a state of 'possession' is, it appears, the opposite of
being in a state of 'privation', just as 'positives' and
'privatives' themselves are opposite. There is the same type of
antithesis in both cases; for just as blindness is opposed to sight,
so is being blind opposed to having sight.

That which is affirmed or denied is not itself affirmation or
denial. By 'affirmation' we mean an affirmative proposition, by
'denial' a negative. Now, those facts which form the matter of the
affirmation or denial are not propositions; yet these two are said
to be opposed in the same sense as the affirmation and denial, for
in this case also the type of antithesis is the same. For as the
affirmation is opposed to the denial, as in the two propositions 'he
sits', 'he does not sit', so also the fact which constitutes the
matter of the proposition in one case is opposed to that in the other,
his sitting, that is to say, to his not sitting.

It is evident that 'positives' and 'privatives' are not opposed each
to each in the same sense as relatives. The one is not explained by
reference to the other; sight is not sight of blindness, nor is any
other preposition used to indicate the relation. Similarly blindness
is not said to be blindness of sight, but rather, privation of
sight. Relatives, moreover, reciprocate; if blindness, therefore, were
a relative, there would be a reciprocity of relation between it and
that with which it was correlative. But this is not the case. Sight is
not called the sight of blindness.

That those terms which fall under the heads of 'positives' and
'privatives' are not opposed each to each as contraries, either, is
plain from the following facts: Of a pair of contraries such that they
have no intermediate, one or the other must needs be present in the
subject in which they naturally subsist, or of which they are
predicated; for it is those, as we proved,' in the case of which
this necessity obtains, that have no intermediate. Moreover, we
cited health and disease, odd and even, as instances. But those
contraries which have an intermediate are not subject to any such
necessity. It is not necessary that every substance, receptive of such
qualities, should be either black or white, cold or hot, for something
intermediate between these contraries may very well be present in
the subject. We proved, moreover, that those contraries have an
intermediate in the case of which the said necessity does not
obtain. Yet when one of the two contraries is a constitutive
property of the subject, as it is a constitutive property of fire to
be hot, of snow to be white, it is necessary determinately that one of
the two contraries, not one or the other, should be present in the
subject; for fire cannot be cold, or snow black. Thus, it is not the
case here that one of the two must needs be present in every subject
receptive of these qualities, but only in that subject of which the
one forms a constitutive property. Moreover, in such cases it is one
member of the pair determinately, and not either the one or the other,
which must be present.

In the case of 'positives' and 'privatives', on the other hand,
neither of the aforesaid statements holds good. For it is not
necessary that a subject receptive of the qualities should always have
either the one or the other; that which has not yet advanced to the
state when sight is natural is not said either to be blind or to
see. Thus 'positives' and 'privatives' do not belong to that class
of contraries which consists of those which have no intermediate. On
the other hand, they do not belong either to that class which consists
of contraries which have an intermediate. For under certain conditions
it is necessary that either the one or the other should form part of
the constitution of every appropriate subject. For when a thing has
reached the stage when it is by nature capable of sight, it will be
said either to see or to be blind, and that in an indeterminate sense,
signifying that the capacity may be either present or absent; for it
is not necessary either that it should see or that it should be blind,
but that it should be either in the one state or in the other. Yet
in the case of those contraries which have an intermediate we found
that it was never necessary that either the one or the other should be
present in every appropriate subject, but only that in certain
subjects one of the pair should be present, and that in a
determinate sense. It is, therefore, plain that 'positives' and
'privatives' are not opposed each to each in either of the senses in
which contraries are opposed.

Again, in the case of contraries, it is possible that there should
be changes from either into the other, while the subject retains its
identity, unless indeed one of the contraries is a constitutive
property of that subject, as heat is of fire. For it is possible
that that that which is healthy should become diseased, that which
is white, black, that which is cold, hot, that which is good, bad,
that which is bad, good. The bad man, if he is being brought into a
better way of life and thought, may make some advance, however slight,
and if he should once improve, even ever so little, it is plain that
he might change completely, or at any rate make very great progress;
for a man becomes more and more easily moved to virtue, however
small the improvement was at first. It is, therefore, natural to
suppose that he will make yet greater progress than he has made in the
past; and as this process goes on, it will change him completely and
establish him in the contrary state, provided he is not hindered by
lack of time. In the case of 'positives' and 'privatives', however,
change in both directions is impossible. There may be a change from
possession to privation, but not from privation to possession. The man
who has become blind does not regain his sight; the man who has become
bald does not regain his hair; the man who has lost his teeth does not
grow his grow a new set. (iv) Statements opposed as affirmation and
negation belong manifestly to a class which is distinct, for in this
case, and in this case only, it is necessary for the one opposite to
be true and the other false.

Neither in the case of contraries, nor in the case of
correlatives, nor in the case of 'positives' and 'privatives', is it
necessary for one to be true and the other false. Health and disease
are contraries: neither of them is true or false. 'Double' and
'half' are opposed to each other as correlatives: neither of them is
true or false. The case is the same, of course, with regard to
'positives' and 'privatives' such as 'sight' and 'blindness'. In
short, where there is no sort of combination of words, truth and
falsity have no place, and all the opposites we have mentioned so
far consist of simple words.

At the same time, when the words which enter into opposed statements
are contraries, these, more than any other set of opposites, would
seem to claim this characteristic. 'Socrates is ill' is the contrary
of 'Socrates is well', but not even of such composite expressions is
it true to say that one of the pair must always be true and the
other false. For if Socrates exists, one will be true and the other
false, but if he does not exist, both will be false; for neither
'Socrates is ill' nor 'Socrates is well' is true, if Socrates does not
exist at all.

In the case of 'positives' and 'privatives', if the subject does not
exist at all, neither proposition is true, but even if the subject
exists, it is not always the fact that one is true and the other
false. For 'Socrates has sight' is the opposite of 'Socrates is blind'
in the sense of the word 'opposite' which applies to possession and
privation. Now if Socrates exists, it is not necessary that one should
be true and the other false, for when he is not yet able to acquire
the power of vision, both are false, as also if Socrates is altogether
non-existent.

But in the case of affirmation and negation, whether the subject
exists or not, one is always false and the other true. For manifestly,
if Socrates exists, one of the two propositions 'Socrates is ill',
'Socrates is not ill', is true, and the other false. This is
likewise the case if he does not exist; for if he does not exist, to
say that he is ill is false, to say that he is not ill is true. Thus
it is in the case of those opposites only, which are opposite in the
sense in which the term is used with reference to affirmation and
negation, that the rule holds good, that one of the pair must be
true and the other false.

11

That the contrary of a good is an evil is shown by induction: the
contrary of health is disease, of courage, cowardice, and so on. But
the contrary of an evil is sometimes a good, sometimes an evil. For
defect, which is an evil, has excess for its contrary, this also being
an evil, and the mean. which is a good, is equally the contrary of the
one and of the other. It is only in a few cases, however, that we
see instances of this: in most, the contrary of an evil is a good.

In the case of contraries, it is not always necessary that if one
exists the other should also exist: for if all become healthy there
will be health and no disease, and again, if everything turns white,
there will be white, but no black. Again, since the fact that Socrates
is ill is the contrary of the fact that Socrates is well, and two
contrary conditions cannot both obtain in one and the same
individual at the same time, both these contraries could not exist
at once: for if that Socrates was well was a fact, then that
Socrates was ill could not possibly be one.

It is plain that contrary attributes must needs be present in
subjects which belong to the same species or genus. Disease and health
require as their subject the body of an animal; white and black
require a body, without further qualification; justice and injustice
require as their subject the human soul.

Moreover, it is necessary that pairs of contraries should in all
cases either belong to the same genus or belong to contrary genera
or be themselves genera. White and black belong to the same genus,
colour; justice and injustice, to contrary genera, virtue and vice;
while good and evil do not belong to genera, but are themselves actual
genera, with terms under them.

12

There are four senses in which one thing can be said to be 'prior'
to another. Primarily and most properly the term has reference to
time: in this sense the word is used to indicate that one thing is
older or more ancient than another, for the expressions 'older' and
'more ancient' imply greater length of time.

Secondly, one thing is said to be 'prior' to another when the
sequence of their being cannot be reversed. In this sense 'one' is
'prior' to 'two'. For if 'two' exists, it follows directly that
'one' must exist, but if 'one' exists, it does not follow
necessarily that 'two' exists: thus the sequence subsisting cannot
be reversed. It is agreed, then, that when the sequence of two
things cannot be reversed, then that one on which the other depends is
called 'prior' to that other.

In the third place, the term 'prior' is used with reference to any
order, as in the case of science and of oratory. For in sciences which
use demonstration there is that which is prior and that which is
posterior in order; in geometry, the elements are prior to the
propositions; in reading and writing, the letters of the alphabet
are prior to the syllables. Similarly, in the case of speeches, the
exordium is prior in order to the narrative.

Besides these senses of the word, there is a fourth. That which is
better and more honourable is said to have a natural priority. In
common parlance men speak of those whom they honour and love as
'coming first' with them. This sense of the word is perhaps the most
far-fetched.

Such, then, are the different senses in which the term 'prior' is
used.

Yet it would seem that besides those mentioned there is yet another.
For in those things, the being of each of which implies that of the
other, that which is in any way the cause may reasonably be said to be
by nature 'prior' to the effect. It is plain that there are
instances of this. The fact of the being of a man carries with it
the truth of the proposition that he is, and the implication is
reciprocal: for if a man is, the proposition wherein we allege that he
is true, and conversely, if the proposition wherein we allege that
he is true, then he is. The true proposition, however, is in no way
the cause of the being of the man, but the fact of the man's being
does seem somehow to be the cause of the truth of the proposition, for
the truth or falsity of the proposition depends on the fact of the
man's being or not being.

Thus the word 'prior' may be used in five senses.

13

The term 'simultaneous' is primarily and most appropriately
applied to those things the genesis of the one of which is
simultaneous with that of the other; for in such cases neither is
prior or posterior to the other. Such things are said to be
simultaneous in point of time. Those things, again, are 'simultaneous'
in point of nature, the being of each of which involves that of the
other, while at the same time neither is the cause of the other's
being. This is the case with regard to the double and the half, for
these are reciprocally dependent, since, if there is a double, there
is also a half, and if there is a half, there is also a double,
while at the same time neither is the cause of the being of the other.

Again, those species which are distinguished one from another and
opposed one to another within the same genus are said to be
'simultaneous' in nature. I mean those species which are
distinguished each from each by one and the same method of division.
Thus the 'winged' species is simultaneous with the 'terrestrial' and
the 'water' species. These are distinguished within the same genus,
and are opposed each to each, for the genus 'animal' has the 'winged',
the 'terrestrial', and the 'water' species, and no one of these is
prior or posterior to another; on the contrary, all such things appear
to be 'simultaneous' in nature. Each of these also, the terrestrial,
the winged, and the water species, can be divided again into
subspecies. Those species, then, also will be 'simultaneous' point
of nature, which, belonging to the same genus, are distinguished
each from each by one and the same method of differentiation.

But genera are prior to species, for the sequence of their being
cannot be reversed. If there is the species 'water-animal', there will
be the genus 'animal', but granted the being of the genus 'animal', it
does not follow necessarily that there will be the species
'water-animal'.

Those things, therefore, are said to be 'simultaneous' in nature,
the being of each of which involves that of the other, while at the
same time neither is in any way the cause of the other's being;
those species, also, which are distinguished each from each and
opposed within the same genus. Those things, moreover, are
'simultaneous' in the unqualified sense of the word which come into
being at the same time.

14

There are six sorts of movement: generation, destruction,
increase, diminution, alteration, and change of place.

It is evident in all but one case that all these sorts of movement
are distinct each from each. Generation is distinct from
destruction, increase and change of place from diminution, and so
on. But in the case of alteration it may be argued that the process
necessarily implies one or other of the other five sorts of motion.
This is not true, for we may say that all affections, or nearly all,
produce in us an alteration which is distinct from all other sorts
of motion, for that which is affected need not suffer either
increase or diminution or any of the other sorts of motion. Thus
alteration is a distinct sort of motion; for, if it were not, the
thing altered would not only be altered, but would forthwith
necessarily suffer increase or diminution or some one of the other
sorts of motion in addition; which as a matter of fact is not the
case. Similarly that which was undergoing the process of increase or
was subject to some other sort of motion would, if alteration were not
a distinct form of motion, necessarily be subject to alteration
also. But there are some things which undergo increase but yet not
alteration. The square, for instance, if a gnomon is applied to it,
undergoes increase but not alteration, and so it is with all other
figures of this sort. Alteration and increase, therefore, are
distinct.

Speaking generally, rest is the contrary of motion. But the
different forms of motion have their own contraries in other forms;
thus destruction is the contrary of generation, diminution of
increase, rest in a place, of change of place. As for this last,
change in the reverse direction would seem to be most truly its
contrary; thus motion upwards is the contrary of motion downwards
and vice versa.

In the case of that sort of motion which yet remains, of those
that have been enumerated, it is not easy to state what is its
contrary. It appears to have no contrary, unless one should define the
contrary here also either as 'rest in its quality' or as 'change in
the direction of the contrary quality', just as we defined the
contrary of change of place either as rest in a place or as change
in the reverse direction. For a thing is altered when change of
quality takes place; therefore either rest in its quality or change in
the direction of the contrary may be called the contrary of this
qualitative form of motion. In this way becoming white is the contrary
of becoming black; there is alteration in the contrary direction,
since a change of a qualitative nature takes place.

15

The term 'to have' is used in various senses. In the first place
it is used with reference to habit or disposition or any other
quality, for we are said to 'have' a piece of knowledge or a virtue.
Then, again, it has reference to quantity, as, for instance, in the
case of a man's height; for he is said to 'have' a height of three
or four cubits. It is used, moreover, with regard to apparel, a man
being said to 'have' a coat or tunic; or in respect of something which
we have on a part of ourselves, as a ring on the hand: or in respect
of something which is a part of us, as hand or foot. The term refers
also to content, as in the case of a vessel and wheat, or of a jar and
wine; a jar is said to 'have' wine, and a corn-measure wheat. The
expression in such cases has reference to content. Or it refers to
that which has been acquired; we are said to 'have' a house or a
field. A man is also said to 'have' a wife, and a wife a husband,
and this appears to be the most remote meaning of the term, for by the
use of it we mean simply that the husband lives with the wife.

Other senses of the word might perhaps be found, but the most
ordinary ones have all been enumerated.

-THE END-


350 BC

HISTORY OF ANIMALS

by Aristotle

translated by D'Arcy Wentworth Thompson

Book I

1

OF the parts of animals some are simple: to wit, all such as
divide into parts uniform with themselves, as flesh into flesh; others
are composite, such as divide into parts not uniform with
themselves, as, for instance, the hand does not divide into hands
nor the face into faces.

And of such as these, some are called not parts merely, but limbs
or members. Such are those parts that, while entire in themselves,
have within themselves other diverse parts: as for instance, the head,
foot, hand, the arm as a whole, the chest; for these are all in
themselves entire parts, and there are other diverse parts belonging
to them.

All those parts that do not subdivide into parts uniform with
themselves are composed of parts that do so subdivide, for instance,
hand is composed of flesh, sinews, and bones. Of animals, some
resemble one another in all their parts, while others have parts
wherein they differ. Sometimes the parts are identical in form or
species, as, for instance, one man's nose or eye resembles another
man's nose or eye, flesh flesh, and bone bone; and in like manner with
a horse, and with all other animals which we reckon to be of one and
the same species: for as the whole is to the whole, so each to each
are the parts severally. In other cases the parts are identical,
save only for a difference in the way of excess or defect, as is the
case in such animals as are of one and the same genus. By 'genus' I
mean, for instance, Bird or Fish, for each of these is subject to
difference in respect of its genus, and there are many species of
fishes and of birds.

Within the limits of genera, most of the parts as a rule
exhibit differences through contrast of the property or accident, such
as colour and shape, to which they are subject: in that some are
more and some in a less degree the subject of the same property or
accident; and also in the way of multitude or fewness, magnitude or
parvitude, in short in the way of excess or defect. Thus in some the
texture of the flesh is soft, in others firm; some have a long bill,
others a short one; some have abundance of feathers, others have
only a small quantity. It happens further that some have parts that
others have not: for instance, some have spurs and others not, some
have crests and others not; but as a general rule, most parts and
those that go to make up the bulk of the body are either identical
with one another, or differ from one another in the way of contrast
and of excess and defect. For 'the more' and 'the less' may be
represented as 'excess' or 'defect'.

Once again, we may have to do with animals whose parts are
neither identical in form nor yet identical save for differences in
the way of excess or defect: but they are the same only in the way
of analogy, as, for instance, bone is only analogous to fish-bone,
nail to hoof, hand to claw, and scale to feather; for what the feather
is in a bird, the scale is in a fish.

The parts, then, which animals severally possess are diverse
from, or identical with, one another in the fashion above described.
And they are so furthermore in the way of local disposition: for
many animals have identical organs that differ in position; for
instance, some have teats in the breast, others close to the thighs.

Of the substances that are composed of parts uniform (or
homogeneous) with themselves, some are soft and moist, others are
dry and solid. The soft and moist are such either absolutely or so
long as they are in their natural conditions, as, for instance, blood,
serum, lard, suet, marrow, sperm, gall, milk in such as have it
flesh and the like; and also, in a different way, the superfluities,
as phlegm and the excretions of the belly and the bladder. The dry and
solid are such as sinew, skin, vein, hair, bone, gristle, nail, horn
(a term which as applied to the part involves an ambiguity, since
the whole also by virtue of its form is designated horn), and such
parts as present an analogy to these.

Animals differ from one another in their modes of subsistence,
in their actions, in their habits, and in their parts. Concerning
these differences we shall first speak in broad and general terms, and
subsequently we shall treat of the same with close reference to each
particular genus.

Differences are manifested in modes of subsistence, in habits, in
actions performed. For instance, some animals live in water and others
on land. And of those that live in water some do so in one way, and
some in another: that is to say, some live and feed in the water, take
in and emit water, and cannot live if deprived of water, as is the
case with the great majority of fishes; others get their food and
spend their days in the water, but do not take in water but air, nor
do they bring forth in the water. Many of these creatures are
furnished with feet, as the otter, the beaver, and the crocodile; some
are furnished with wings, as the diver and the grebe; some are
destitute of feet, as the water-snake. Some creatures get their living
in the water and cannot exist outside it: but for all that do not take
in either air or water, as, for instance, the sea-nettle and the
oyster.
And of creatures that live in the water some live in the
sea, some in rivers, some in lakes, and some in marshes, as the frog
and the newt.

Of animals that live on dry land some take in air and emit it,
which phenomena are termed 'inhalation' and 'exhalation'; as, for
instance, man and all such land animals as are furnished with lungs.
Others, again, do not inhale air, yet live and find their sustenance
on dry land; as, for instance, the wasp, the bee, and all other
insects. And by 'insects' I mean such creatures as have nicks or
notches on their bodies, either on their bellies or on both backs
and bellies.

And of land animals many, as has been said, derive their
subsistence from the water; but of creatures that live in and inhale
water not a single one derives its subsistence from dry land.

Some animals at first live in water, and by and by change their
shape and live out of water, as is the case with river worms, for
out of these the gadfly develops.

Furthermore, some animals are stationary, and some are erratic.
Stationary animals are found in water, but no such creature is found
on dry land. In the water are many creatures that live in close
adhesion to an external object, as is the case with several kinds of
oyster. And, by the way, the sponge appears to be endowed with a
certain sensibility: as a proof of which it is alleged that the
difficulty in detaching it from its moorings is increased if the
movement to detach it be not covertly applied.

Other creatures adhere at one time to an object and detach
themselves from it at other times, as is the case with a species of
the so-called sea-nettle; for some of these creatures seek their
food in the night-time loose and unattached.

Many creatures are unattached but motionless, as is the case with
oysters and the so-called holothuria. Some can swim, as, for instance,
fishes, molluscs, and crustaceans, such as the crawfish. But some of
these last move by walking, as the crab, for it is the nature of the
creature, though it lives in water, to move by walking.

Of land animals some are furnished with wings, such as birds
and bees, and these are so furnished in different ways one from
another; others are furnished with feet. Of the animals that are
furnished with feet some walk, some creep, and some wriggle. But no
creature is able only to move by flying, as the fish is able only to
swim, for the animals with leathern wings can walk; the bat has feet
and the seal has imperfect feet.

Some birds have feet of little power, and are therefore called
Apodes. This little bird is powerful on the wing; and, as a rule,
birds that resemble it are weak-footed and strong winged, such as
the swallow and the drepanis or (? ) Alpine swift; for all these
birds resemble one another in their habits and in their plumage, and
may easily be mistaken one for another. (The apus is to be seen at all
seasons, but the drepanis only after rainy weather in summer; for this
is the time when it is seen and captured, though, as a general rule,
it is a rare bird. )

Again, some animals move by walking on the ground as well as by
swimming in water.

Furthermore, the following differences are manifest in their
modes of living and in their actions. Some are gregarious, some are
solitary, whether they be furnished with feet or wings or be fitted
for a life in the water; and some partake of both characters, the
solitary and the gregarious. And of the gregarious, some are
disposed to combine for social purposes, others to live each for its
own self.

Gregarious creatures are, among birds, such as the pigeon, the
crane, and the swan; and, by the way, no bird furnished with crooked
talons is gregarious. Of creatures that live in water many kinds of
fishes are gregarious, such as the so-called migrants, the tunny,
the pelamys, and the bonito.

Man, by the way, presents a mixture of the two characters, the
gregarious and the solitary.

Social creatures are such as have some one common object in view;
and this property is not common to all creatures that are
gregarious. Such social creatures are man, the bee, the wasp, the ant,
and the crane.

Again, of these social creatures some submit to a ruler, others
are subject to no governance: as, for instance, the crane and the
several sorts of bee submit to a ruler, whereas ants and numerous
other creatures are every one his own master.

And again, both of gregarious and of solitary animals, some are
attached to a fixed home and others are erratic or nomad.

Also, some are carnivorous, some graminivorous, some omnivorous:
whilst some feed on a peculiar diet, as for instance the bees and
the spiders, for the bee lives on honey and certain other sweets,
and the spider lives by catching flies; and some creatures live on
fish. Again, some creatures catch their food, others treasure it up;
whereas others do not so.

Some creatures provide themselves with a dwelling, others go
without one: of the former kind are the mole, the mouse, the ant,
the bee; of the latter kind are many insects and quadrupeds.
Further, in respect to locality of dwelling place, some creatures
dwell under ground, as the lizard and the snake; others live on the
surface of the ground, as the horse and the dog. make to themselves
holes, others do not

Some are nocturnal, as the owl and the bat; others live in the
daylight.

Moreover, some creatures are tame and some are wild: some are
at all times tame, as man and the mule; others are at all times
savage, as the leopard and the wolf; and some creatures can be rapidly
tamed, as the elephant.

Again, we may regard animals in another light. For, whenever a
race of animals is found domesticated, the same is always to be
found in a wild condition; as we find to be the case with horses,
kine, swine, (men), sheep, goats, and dogs.

Further, some animals emit sound while others are mute, and
some are endowed with voice: of these latter some have articulate
speech, while others are inarticulate; some are given to continual
chirping and twittering some are prone to silence; some are musical,
and some unmusical; but all animals without exception exercise their
power of singing or chattering chiefly in connexion with the
intercourse of the sexes.

Again, some creatures live in the fields, as the cushat; some
on the mountains, as the hoopoe; some frequent the abodes of men, as
the pigeon.

Some, again, are peculiarly salacious, as the partridge, the
barn-door cock and their congeners; others are inclined to chastity,
as the whole tribe of crows, for birds of this kind indulge but rarely
in sexual intercourse.

Of marine animals, again, some live in the open seas, some near
the shore, some on rocks.

Furthermore, some are combative under offence; others are
provident for defence. Of the former kind are such as act as
aggressors upon others or retaliate when subjected to ill usage, and
of the latter kind are such as merely have some means of guarding
themselves against attack.

Animals also differ from one another in regard to character in
the following respects. Some are good-tempered, sluggish, and little
prone to ferocity, as the ox; others are quick tempered, ferocious and
unteachable, as the wild boar; some are intelligent and timid, as
the stag and the hare; others are mean and treacherous, as the
snake; others are noble and courageous and high-bred, as the lion;
others are thorough-bred and wild and treacherous, as the wolf: for,
by the way, an animal is highbred if it come from a noble stock, and
an animal is thorough-bred if it does not deflect from its racial
characteristics.

Further, some are crafty and mischievous, as the fox; some are
spirited and affectionate and fawning, as the dog; others are
easy-tempered and easily domesticated, as the elephant; others are
cautious and watchful, as the goose; others are jealous and
self-conceited, as the peacock. But of all animals man alone is
capable of deliberation.

Many animals have memory, and are capable of instruction; but no
other creature except man can recall the past at will.

With regard to the several genera of animals, particulars as to
their habits of life and modes of existence will be discussed more
fully by and by.

2

Common to all animals are the organs whereby they take food and
the organs where into they take it; and these are either identical
with one another, or are diverse in the ways above specified: to
wit, either identical in form, or varying in respect of excess or
defect, or resembling one another analogically, or differing in
position.

Furthermore, the great majority of animals have other organs
besides these in common, whereby they discharge the residuum of
their food: I say, the great majority, for this statement does not
apply to all. And, by the way, the organ whereby food is taken in is
called the mouth, and the organ whereinto it is taken, the belly;
the remainder of the alimentary system has a great variety of names.

Now the residuum of food is twofold in kind, wet and dry, and
such creatures as have organs receptive of wet residuum are invariably
found with organs receptive of dry residuum; but such as have organs
receptive of dry residuum need not possess organs receptive of wet
residuum. In other words, an animal has a bowel or intestine if it
have a bladder; but an animal may have a bowel and be without a
bladder. And, by the way, I may here remark that the organ receptive
of wet residuum is termed 'bladder', and the organ receptive of dry
residuum 'intestine or 'bowel'.

3

Of animals otherwise, a great many have, besides the organs
above-mentioned, an organ for excretion of the sperm: and of animals
capable of generation one secretes into another, and the other into
itself. The latter is termed 'female', and the former 'male'; but some
animals have neither male nor female. Consequently, the organs
connected with this function differ in form, for some animals have a
womb and others an organ analogous thereto.

The above-mentioned organs, then, are the most indispensable parts
of animals; and with some of them all animals without exception, and
with others animals for the most part, must needs be provided.

One sense, and one alone, is common to all animals-the sense of
touch. Consequently, there is no special name for the organ in which
it has its seat; for in some groups of animals the organ is identical,
in others it is only analogous.

4

Every animal is supplied with moisture, and, if the animal be
deprived of the same by natural causes or artificial means, death
ensues: further, every animal has another part in which the moisture
is contained. These parts are blood and vein, and in other animals
there is something to correspond; but in these latter the parts are
imperfect, being merely fibre and serum or lymph.

Touch has its seat in a part uniform and homogeneous, as in the
flesh or something of the kind, and generally, with animals supplied
with blood, in the parts charged with blood. In other animals it has
its seat in parts analogous to the parts charged with blood; but in
all cases it is seated in parts that in their texture are homogeneous.

The active faculties, on the contrary, are seated in the parts
that are heterogeneous: as, for instance, the business of preparing
the food is seated in the mouth, and the office of locomotion in the
feet, the wings, or in organs to correspond.

Again, some animals are supplied with blood, as man, the horse,
and all such animals as are, when full-grown, either destitute of
feet, or two-footed, or four-footed; other animals are bloodless, such
as the bee and the wasp, and, of marine animals, the cuttle-fish,
the crawfish, and all such animals as have more than four feet.

5

Again, some animals are viviparous, others oviparous, others
vermiparous or 'grub-bearing'. Some are viviparous, such as man, the
horse, the seal, and all other animals that are hair-coated, and, of
marine animals, the cetaceans, as the dolphin, and the so-called
Selachia. (Of these latter animals, some have a tubular air-passage
and no gills, as the dolphin and the whale: the dolphin with the
air-passage going through its back, the whale with the air-passage
in its forehead; others have uncovered gills, as the Selachia, the
sharks and rays. )

What we term an egg is a certain completed result of conception
out of which the animal that is to be develops, and in such a way that
in respect to its primitive germ it comes from part only of the egg,
while the rest serves for food as the germ develops. A 'grub' on the
other hand is a thing out of which in its entirety the animal in its
entirety develops, by differentiation and growth of the embryo.

Of viviparous animals, some hatch eggs in their own interior,
as creatures of the shark kind; others engender in their interior a
live foetus, as man and the horse. When the result of conception is
perfected, with some animals a living creature is brought forth,
with others an egg is brought to light, with others a grub. Of the
eggs, some have egg-shells and are of two different colours within,
such as birds' eggs; others are soft-skinned and of uniform colour, as
the eggs of animals of the shark kind. Of the grubs, some are from the
first capable of movement, others are motionless. However, with regard
to these phenomena we shall speak precisely hereafter when we come
to treat of Generation.

Furthermore, some animals have feet and some are destitute
thereof. Of such as have feet some animals have two, as is the case
with men and birds, and with men and birds only; some have four, as
the lizard and the dog; some have more, as the centipede and the
bee; but allsoever that have feet have an even number of them.

Of swimming creatures that are destitute of feet, some have
winglets or fins, as fishes: and of these some have four fins, two
above on the back, two below on the belly, as the gilthead and the
basse; some have two only,-to wit, such as are exceedingly long and
smooth, as the eel and the conger; some have none at all, as the
muraena, but use the sea just as snakes use dry ground-and by the way,
snakes swim in water in just the same way. Of the shark-kind some have
no fins, such as those that are flat and long-tailed, as the ray and
the sting-ray, but these fishes swim actually by the undulatory motion
of their flat bodies; the fishing frog, however, has fins, and so
likewise have all such fishes as have not their flat surfaces
thinned off to a sharp edge.

Of those swimming creatures that appear to have feet, as is the
case with the molluscs, these creatures swim by the aid of their
feet and their fins as well, and they swim most rapidly backwards in
the direction of the trunk, as is the case with the cuttle-fish or
sepia and the calamary; and, by the way, neither of these latter can
walk as the poulpe or octopus can.

The hard-skinned or crustaceous animals, like the crawfish,
swim by the instrumentality of their tail-parts; and they swim most
rapidly tail foremost, by the aid of the fins developed upon that
member. The newt swims by means of its feet and tail; and its tail
resembles that of the sheatfish, to compare little with great.

Of animals that can fly some are furnished with feathered wings,
as the eagle and the hawk; some are furnished with membranous wings,
as the bee and the cockchafer; others are furnished with leathern
wings, as the flying fox and the bat. All flying creatures possessed
of blood have feathered wings or leathern wings; the bloodless
creatures have membranous wings, as insects. The creatures that have
feathered wings or leathern wings have either two feet or no feet at
all: for there are said to be certain flying serpents in Ethiopia that
are destitute of feet.

Creatures that have feathered wings are classed as a genus
under the name of 'bird'; the other two genera, the leathern-winged
and membrane-winged, are as yet without a generic title.

Of creatures that can fly and are bloodless some are coleopterous
or sheath-winged, for they have their wings in a sheath or shard, like
the cockchafer and the dung-beetle; others are sheathless, and of
these latter some are dipterous and some tetrapterous: tetrapterous,
such as are comparatively large or have their stings in the tail,
dipterous, such as are comparatively small or have their stings in
front. The coleoptera are, without exception, devoid of stings; the
diptera have the sting in front, as the fly, the horsefly, the gadfly,
and the gnat.

Bloodless animals as a general rule are inferior in point of size
to blooded animals; though, by the way, there are found in the sea
some few bloodless creatures of abnormal size, as in the case of
certain molluscs. And of these bloodless genera, those are the largest
that dwell in milder climates, and those that inhabit the sea are
larger than those living on dry land or in fresh water.

All creatures that are capable of motion move with four or more
points of motion; the blooded animals with four only: as, for
instance, man with two hands and two feet, birds with two wings and
two feet, quadrupeds and fishes severally with four feet and four
fins. Creatures that have two winglets or fins, or that have none at
all like serpents, move all the same with not less than four points of
motion; for there are four bends in their bodies as they move, or
two bends together with their fins. Bloodless and many footed animals,
whether furnished with wings or feet, move with more than four
points of motion; as, for instance, the dayfly moves with four feet
and four wings: and, I may observe in passing, this creature is
exceptional not only in regard to the duration of its existence,
whence it receives its name, but also because though a quadruped it
has wings also.

All animals move alike, four-footed and many-footed; in other
words, they all move cross-corner-wise. And animals in general have
two feet in advance; the crab alone has four.

6

Very extensive genera of animals, into which other subdivisions
fall, are the following: one, of birds; one, of fishes; and another,
of cetaceans. Now all these creatures are blooded.

There is another genus of the hard-shell kind, which is called
oyster; another of the soft-shell kind, not as yet designated by a
single term, such as the spiny crawfish and the various kinds of crabs
and lobsters; and another of molluscs, as the two kinds of calamary
and the cuttle-fish; that of insects is different. All these latter
creatures are bloodless, and such of them as have feet have a goodly
number of them; and of the insects some have wings as well as feet.

Of the other animals the genera are not extensive. For in them
one species does not comprehend many species; but in one case, as man,
the species is simple, admitting of no differentiation, while other
cases admit of differentiation, but the forms lack particular
designations.

So, for instance, creatures that are qudapedal and unprovided
with wings are blooded without exception, but some of them are
viviparous, and some oviparous. Such as are viviparous are
hair-coated, and such as are oviparous are covered with a kind of
tessellated hard substance; and the tessellated bits of this substance
are, as it were, similar in regard to position to a scale.

An animal that is blooded and capable of movement on dry land,
but is naturally unprovided with feet, belongs to the serpent genus;
and animals of this genus are coated with the tessellated horny
substance. Serpents in general are oviparous; the adder, an
exceptional case, is viviparous: for not all viviparous animals are
hair-coated, and some fishes also are viviparous.

All animals, however, that are hair-coated are viviparous. For,
by the way, one must regard as a kind of hair such prickly hairs as
hedgehogs and porcupines carry; for these spines perform the office of
hair, and not of feet as is the case with similar parts of
sea-urchins.

In the genus that combines all viviparous quadrupeds are many
species, but under no common appellation. They are only named as it
were one by one, as we say man, lion, stag, horse, dog, and so on;
though, by the way, there is a sort of genus that embraces all
creatures that have bushy manes and bushy tails, such as the horse,
the ass, the mule, the jennet, and the animals that are called Hemioni
in Syria,-from their externally resembling mules, though they are
not strictly of the same species. And that they are not so is proved
by the fact that they mate with and breed from one another. For all
these reasons, we must take animals species by species, and discuss
their peculiarities severally'

These preceding statements, then, have been put forward thus in a
general way, as a kind of foretaste of the number of subjects and of
the properties that we have to consider in order that we may first get
a clear notion of distinctive character and common properties. By
and by we shall discuss these matters with greater minuteness.

After this we shall pass on to the discussion of causes. For to do
this when the investigation of the details is complete is the proper
and natural method, and that whereby the subjects and the premisses of
our argument will afterwards be rendered plain.

In the first place we must look to the constituent parts of
animals. For it is in a way relative to these parts, first and
foremost, that animals in their entirety differ from one another:
either in the fact that some have this or that, while they have not
that or this; or by peculiarities of position or of arrangement; or by
the differences that have been previously mentioned, depending upon
diversity of form, or excess or defect in this or that particular,
on analogy, or on contrasts of the accidental qualities.

To begin with, we must take into consideration the parts of
Man. For, just as each nation is wont to reckon by that monetary
standard with which it is most familiar, so must we do in other
matters. And, of course, man is the animal with which we are all of us
the most familiar.

Now the parts are obvious enough to physical perception. However,
with the view of observing due order and sequence and of combining
rational notions with physical perception, we shall proceed to
enumerate the parts: firstly, the organic, and afterwards the simple
or non-composite.

7

The chief parts into which the body as a whole is subdivided,
are the head, the neck, the trunk (extending from the neck to the
privy parts), which is called the thorax, two arms and two legs.

Of the parts of which the head is composed the hair-covered
portion is called the 'skull'. The front portion of it is termed
'bregma' or 'sinciput', developed after birth-for it is the last of
all the bones in the body to acquire solidity,-the hinder part is
termed the 'occiput', and the part intervening between the sinciput
and the occiput is the 'crown'. The brain lies underneath the
sinciput; the occiput is hollow. The skull consists entirely of thin
bone, rounded in shape, and contained within a wrapper of fleshless
skin.

The skull has sutures: one, of circular form, in the case of
women; in the case of men, as a general rule, three meeting at a
point. Instances have been known of a man's skull devoid of suture
altogether. In the skull the middle line, where the hair parts, is
called the crown or vertex. In some cases the parting is double;
that is to say, some men are double crowned, not in regard to the bony
skull, but in consequence of the double fall or set of the hair.

8

The part that lies under the skull is called the 'face': but in
the case of man only, for the term is not applied to a fish or to an
ox. In the face the part below the sinciput and between the eyes is
termed the forehead. When men have large foreheads, they are slow to
move; when they have small ones, they are fickle; when they have broad
ones, they are apt to be distraught; when they have foreheads
rounded or bulging out, they are quick-tempered.

9

Underneath the forehead are two eyebrows. Straight eyebrows are
a sign of softness of disposition; such as curve in towards the
nose, of harshness; such as curve out towards the temples, of humour
and dissimulation; such as are drawn in towards one another, of
jealousy.

Under the eyebrows come the eyes. These are naturally two in
number. Each of them has an upper and a lower eyelid, and the hairs on
the edges of these are termed 'eyelashes'. The central part of the eye
includes the moist part whereby vision is effected, termed the
'pupil', and the part surrounding it called the 'black'; the part
outside this is the 'white'. A part common to the upper and lower
eyelid is a pair of nicks or corners, one in the direction of the
nose, and the other in the direction of the temples. When these are
long they are a sign of bad disposition; if the side toward the
nostril be fleshy and comb-like, they are a sign of dishonesty.

All animals, as a general rule, are provided with eyes, excepting
the ostracoderms and other imperfect creatures; at all events, all
viviparous animals have eyes, with the exception of the mole. And
yet one might assert that, though the mole has not eyes in the full
sense, yet it has eyes in a kind of a way. For in point of absolute
fact it cannot see, and has no eyes visible externally; but when the
outer skin is removed, it is found to have the place where eyes are
usually situated, and the black parts of the eyes rightly situated,
and all the place that is usually devoted on the outside to eyes:
showing that the parts are stunted in development, and the skin
allowed to grow over.

10

Of the eye the white is pretty much the same in all creatures; but
what is called the black differs in various animals. Some have the rim
black, some distinctly blue, some greyish-blue, some greenish; and
this last colour is the sign of an excellent disposition, and is
particularly well adapted for sharpness of vision. Man is the only, or
nearly the only, creature, that has eyes of diverse colours.
Animals, as a rule, have eyes of one colour only. Some horses have
blue eyes.

Of eyes, some are large, some small, some medium-sized; of these,
the medium-sized are the best. Moreover, eyes sometimes protrude,
sometimes recede, sometimes are neither protruding nor receding. Of
these, the receding eye is in all animals the most acute; but the last
kind are the sign of the best disposition. Again, eyes are sometimes
inclined to wink under observation, sometimes to remain open and
staring, and sometimes are disposed neither to wink nor stare. The
last kind are the sign of the best nature, and of the others, the
latter kind indicates impudence, and the former indecision.

11

Furthermore, there is a portion of the head, whereby an animal
hears, a part incapable of breathing, the 'ear'. I say 'incapable of
breathing', for Alcmaeon is mistaken when he says that goats inspire
through their ears. Of the ear one part is unnamed, the other part
is called the 'lobe'; and it is entirely composed of gristle and
flesh. The ear is constructed internally like the trumpet-shell, and
the innermost bone is like the ear itself, and into it at the end
the sound makes its way, as into the bottom of a jar. This
receptacle does not communicate by any passage with the brain, but
does so with the palate, and a vein extends from the brain towards it.
The eyes also are connected with the brain, and each of them lies at
the end of a little vein. Of animals possessed of ears man is the only
one that cannot move this organ. Of creatures possessed of hearing,
some have ears, whilst others have none, but merely have the
passages for ears visible, as, for example, feathered animals or
animals coated with horny tessellates.

Viviparous animals, with the exception of the seal, the dolphin,
and those others which after a similar fashion to these are cetaceans,
are all provided with ears; for, by the way, the shark-kind are also
viviparous. Now, the seal has the passages visible whereby it hears;
but the dolphin can hear, but has no ears, nor yet any passages
visible. But man alone is unable to move his ears, and all other
animals can move them. And the ears lie, with man, in the same
horizontal plane with the eyes, and not in a plane above them as is
the case with some quadrupeds. Of ears, some are fine, some are
coarse, and some are of medium texture; the last kind are best for
hearing, but they serve in no way to indicate character. Some ears are
large, some small, some medium-sized; again, some stand out far,
some lie in close and tight, and some take up a medium position; of
these such as are of medium size and of medium position are
indications of the best disposition, while the large and outstanding
ones indicate a tendency to irrelevant talk or chattering. The part
intercepted between the eye, the ear, and the crown is termed the
'temple'. Again, there is a part of the countenance that serves as a
passage for the breath, the 'nose'. For a man inhales and exhales by
this organ, and sneezing is effected by its means: which last is an
outward rush of collected breath, and is the only mode of breath
used as an omen and regarded as supernatural. Both inhalation and
exhalation go right on from the nose towards the chest; and with the
nostrils alone and separately it is impossible to inhale or exhale,
owing to the fact that the inspiration and respiration take place from
the chest along the windpipe, and not by any portion connected with
the head; and indeed it is possible for a creature to live without
using this process of nasal respiration.

Again, smelling takes place by means of the nose,-smelling, or the
sensible discrimination of odour. And the nostril admits of easy
motion, and is not, like the ear, intrinsically immovable. A part of
it, composed of gristle, constitutes, a septum or partition, and
part is an open passage; for the nostril consists of two separate
channels. The nostril (or nose) of the elephant is long and strong,
and the animal uses it like a hand; for by means of this organ it
draws objects towards it, and takes hold of them, and introduces its
food into its mouth, whether liquid or dry food, and it is the only
living creature that does so.

Furthermore, there are two jaws; the front part of them
constitutes the chin, and the hinder part the cheek. All animals
move the lower jaw, with the exception of the river crocodile; this
creature moves the upper jaw only.

Next after the nose come two lips, composed of flesh, and
facile of motion. The mouth lies inside the jaws and lips. Parts of
the mouth are the roof or palate and the pharynx.

The part that is sensible of taste is the tongue. The sensation
has its seat at the tip of the tongue; if the object to be tasted be
placed on the flat surface of the organ, the taste is less sensibly
experienced. The tongue is sensitive in all other ways wherein flesh
in general is so: that is, it can appreciate hardness, or warmth and
cold, in any part of it, just as it can appreciate taste. The tongue
is sometimes broad, sometimes narrow, and sometimes of medium width;
the last kind is the best and the clearest in its discrimination of
taste. Moreover, the tongue is sometimes loosely hung, and sometimes
fastened: as in the case of those who mumble and who lisp.

The tongue consists of flesh, soft and spongy, and the so-called
'epiglottis' is a part of this organ.

That part of the mouth that splits into two bits is called the
'tonsils'; that part that splits into many bits, the 'gums'. Both
the tonsils and the gums are composed of flesh. In the gums are teeth,
composed of bone.

Inside the mouth is another part, shaped like a bunch of
grapes, a pillar streaked with veins. If this pillar gets relaxed
and inflamed it is called 'uvula' or 'bunch of grapes', and it then
has a tendency to bring about suffocation.

12

The neck is the part between the face and the trunk. Of this the
front part is the larynx land the back part the ur The front part,
composed of gristle, through which respiration and speech is effected,
is termed the 'windpipe'; the part that is fleshy is the oesophagus,
inside just in front of the chine. The part to the back of the neck is
the epomis, or 'shoulder-point'.

These then are the parts to be met with before you come to the
thorax.