by fire, and they are both of them nothing but the relation which
that substance has to two other bodies, which have a power to operate
differently upon it. For by what right is it that fusibility comes to be
a part of the essence signified by the word gold, and solubility but
a property of it? Or why is its colour part of the essence, and its
malleableness but a property? That which I mean is this, That these
being all but properties, depending on its real constitution, and
nothing but powers, either active or passive, in reference to other
bodies, no one has authority to determine the signification of the
word gold (as referred to such a body existing in nature) more to one
collection of ideas to be found in that body than to another: whereby
the signification of that name must unavoidably be very uncertain.
Since, as has been said, several people observe several properties in
the same substance; and I think I may say nobody all. And therefore we
have but very imperfect descriptions of things, and words have very
uncertain significations.


18. The Names of simple Ideas the least doubtful.

From what has been said, it is easy to observe what has been before
remarked, viz. that the NAMES OF SIMPLE IDEAS are, of all others, the
least liable to mistakes, and that for these reasons. First, Because the
ideas they stand for, being each but one single perception, are much
easier got, and more clearly retained, than the more complex ones, and
therefore are not liable to the uncertainty which usually attends those
compounded ones of substances and mixed modes, in which the precise
number of simple ideas that make them up are not easily agreed, so
readily kept in mind. And, Secondly, Because they are never referred to
any other essence, but barely that perception they immediately signify: