— 329 —
Identity of Substances.       §2. We have the Ideas but of three sorts of Substances; 1. God.
2. Finite Intelligences. 3. Bodies. First, God is without beginning,
eternal, unalterable, and every where; and therefore concerning his
Identity, there can be no doubt. Secondly, Finite Spirits having
had each its determinate time and place of beginning to exist, the
relation to that time and place will always determine to each of
them its Identity as long as it exists.
      Thirdly, The same will hold of every Particle of Matter, to which
no Addition or Substraction of Matter being made, it is the same.
For though these three sorts of Substances, as we term them, do not
exclude one another out of the same place; yet we cannot conceive
but that they must necessarily each of them exclude any of the same
kind out of the same place: Or else the Notions and Names of
Identity and Diversity would be in vain, and there could be no such
distinction of Substances, or any thing else one from another. For
Example, could two Bodies be in the same place at the same time;
then those two parcels of Matter must be one and the same, take
them great or little; nay, all Bodies must be one and the same. For
by the same reason that two particles of Matter may be in one
Identity of Modes. place, all Bodies may be in one place: Which, when it can be sup-
posed, takes away the distinction of Identity and Diversity, of one
and more, and renders it ridiculous. But it being a contradiction,
that two or more should be one, Identity and Diversity are relations
and ways of comparing well founded, and of use to the Under-
standing. All other things being but Modes or Relations ultimately
terminated in Substances, the Identity and Diversity of each
particular Existence of them too will be by the same way deter-
mined: Only as to things whose Existence is in succession, such as
are the Actions of finite Beings, v.g. Motion and Thought, both which
consist in a continued train of Succession, concerning their Diver-
sity there can be no question: Because each perishing the moment it
begins, they cannot exist in different times, or in different places, as
permanent Beings can at different times exist in distant places; and
therefore no motion or thought considered as at different times can
be the same, each part thereof having a different beginning of
Existence.
Locke Hum II, 27, §2, p. 329