e made the
essence of that species to which that name belongs; and there it is
not safe to apply or use them otherwise: but in other cases it is bare
impropriety of speech to apply them contrary to the common usage of
the country. But yet even this too disturbs not the certainty of that
knowledge, which is still to be had by a due contemplation and comparing
of those even nick-named ideas.

11. Thirdly, Our complex Ideas of Substances have their Archetypes
without us; and here knowledge comes short.

THIRDLY, There is another sort of complex ideas, which, being referred
to archetypes without us, may differ from them, and so our knowledge
about them may come short of being real. Such are our ideas of
substances, which, consisting of a collection of simple ideas, supposed
taken from the works of nature, may yet vary from them; by having more
or different ideas united in them than are to be found united in the
things themselves. From whence it comes to pass, that they may, and
often do, fail of being exactly conformable to things themselves.

12. So far as our complex ideas agree with those Archetypes without us,
so far our Knowledge concerning Substances is real.

I say, then, that to have ideas of SUBSTANCES which, by being
conformable to things, may afford us real knowledge, it is not enough,
as in MODES, to put together such ideas as have no inconsistence, though
they did never before so exist: v.g. the ideas of sacrilege or perjury,
&c., were as real and true ideas before, as after the existence of any
such fact. But our ideas of substances, being supposed copies, and
referred to archetypes without us, must still be taken from something
that does or has existed: they must not consist of ideas put together at
the pleasure of our thoughts, without any real pattern they were taken
from, though we can perceive no inconsistence in such a combination. The
reason whereof is because we, knowing not what real constitution it is
of substances whereon our simple ideas depend, and which really is the
cause of the strict union of some of them one with another, and the
exclusion of others; there are very few of them that we can be sure
are or are not inconsistent in nature: any further than experience and
sensible observation reach Herein, therefore, is founded the reality of
our knowledge concerning substances--That all our complex ideas of them
must be such, and such only, as are made up of such simple ones as have
been d