must be explained elsewhere.
We call 'substance' (1) the simple bodies, i.e. earth and fire and
water and everything of the sort, and in general bodies and the things
composed of them, both animals and divine beings, and the parts of
these. All these are called substance because they are not
predicated of a subject but everything else is predicated of them.-(2)
That which, being present in such things as are not predicated of a
subject, is the cause of their being, as the soul is of the being of
an animal.-(3) The parts which are present in such things, limiting
them and marking them as individuals, and by whose destruction the
whole is destroyed, as the body is by the destruction of the plane, as
some say, and the plane by the destruction of the line; and in general
number is thought by some to be of this nature; for if it is
destroyed, they say, nothing exists, and it limits all things.-(4) The
essence, the formula of which is a definition, is also called the
substance of each thing.
It follows, then, that 'substance' has two senses, (A) ultimate
substratum, which is no longer predicated of anything else, and (B)
that which, being a 'this', is also separable and of this nature is
the shape or form of each thing.
'The same' means (1) that which is the same in an accidental
sense, e.g. 'the pale' and 'the musical' are the same because they are
accidents of the same thing, and 'a man' and 'musical' because the one
is an accident of the other; and 'the musical' is 'a man' because it
is an accident of the man. (The complex entity is the same as either
of the simple ones and each of these is the same as it; for both
'the man' and 'the musical' are said to be the same as 'the musical
man', and this the same as they.) This is why all of these
statements are made not universally; for it is not true to say that
every man is the same as 'the musical' (for universal attributes
belong to things in virtue of their own nature, but accidents do not
belong to them in virtue of their own nature); but of the
individuals the statements are made without qualification. For
'Socrates' and 'musical Socrates' are thought to be the same; but
'Socrates' is not predicable of more than one subject, and therefore
we do not say 'every Socrates' as we say 'every man'.
Some things are said to be the same in this sense, others (2)
are the same by their own nature, in as many senses as that which is
one by its own nature is so; for both the things whose matter is one
either in kind or in number, and those whose essence is one, are
said to be the same. Clearly, therefore, sameness is a unity of the
being either of more than one thing or of one thing when it is treated
as more than one, ie. when we say a thing is the same as itself; for
we treat it as two.
Things are called 'other' if either their kinds or their matters
or the definitions of their essence are more than one; and in
general 'other' has meanings opposite to those of 'the same'.
'Different' is applied (1) to those things which though other
are the same in some respect, only not in number but either in species
or in genus or by analogy; (2) to those whose genus is other, and to
contraries, and to an things that have their otherness in their
Those things are called 'like' which have the same attributes in
every respect, and those which have more attributes the same than
different, and those whose quality is one; and that which shares
with another thing the greater number or the more important of the
attributes (each of them one of two contraries) in respect of which
things are capable of altering, is like that other thing. The senses
of 'unlike' are opposite to those of 'like'.