— 615 —
General Propositions concerning Substances are often trifling.
      §9. We having little or no knowledge of what Combinations
there be of simple Ideas existing together in Substances, but by our
Senses, we cannot make any universal certain Propositions concern-
ing them, any farther than our nominal Essences lead us: which
being to a very few and inconsiderable Truths, in respect of those
which depend on their real Constitutions, the general Propositions
that are made about Substances, if they are certain, are for the most part
but trifling; and if they are instructive, are uncertain, and such as we
can have no knowledge of their real Truth, how much soever con-
stant Observation and Analogy may assist our Judgments in guess-
ing. Hence it comes to pass, that one may often meet with very
clear and coherent Discourses, that amount yet to nothing. For ’tis
plain, that Names of substantial Beings, as well as others, as far as
they have relative Significations affixed to them, may, with great
Truth, be joined negatively and affirmatively in Propositions, as
their relative Definitions make them fit to be so joined; and Proposi-
tions consisting of such Terms, may, with the same clearness, be
deduced one from another, as those that convey the most real
Truths; and all this, without any knowledge of the Nature or
Reality of Things existing without us. By this method, one may
make Demonstrations and undoubted Propositions in Words, and
yet thereby advance not one jot in the Knowledge of the Truth of
Things; v.g. he that having learnt these following Words, with
their ordinary mutually relative Acceptations annexed to them;
v.g. Substance, Man, Animal, Farm, Soul, Vegetative, Sensitive, Rational,
may make several undoubted Propositions about the Soul, without
knowing at all what the Soul really is; and of this sort, a Man may
find an infinite number of Propositions, Reasonings, and Conclu-
sions, in Books of Metaphysicks, School-Divinity, and some sort
of natural Philosophy; and after all, know as little of GOD, Spirits,
or Bodies, as he did before he set out.
Locke Hum IV, 8, §9, p. 615