13. To co-existing qualities, which are known but imperfectly.
Secondly, The simple ideas that are found to
co-exist in substances being that which their names immediately signify, these, as united in the several sorts of
things, are the proper standards to which their names are referred, and by which their significations may be best
rectified. But neither will these archetypes so well serve to this purpose as to leave these names without very
various and uncertain significations. Because these simple ideas that co-exist, and are united in the same subject,
being very numerous, and having all an equal right to go into the complex specific idea which the specific name is
to stand for, men, though they propose to themselves the very same subject to consider, yet frame very different
ideas about it; and so the name they use for it unavoidably comes to have, in several men, very different
significations. The simple qualities which make up the complex ideas, being most of them powers, in relation to
changes which they are apt to make in, or receive from other bodies, are almost infinite. He that shall but observe
what a great variety of alterations any one of the baser metals is apt to receive, from the different application only
of fire; and how much a greater number of changes any of them will receive in the hands of a chymist, by the
application of other bodies, will not think it strange that I count the properties of any sort of bodies not easy to be
collected, and completely known, by the ways of inquiry which our faculties are capable of. They being therefore
at least so many, that no man can know the precise and definite number, they are differently discovered by
different men, according to their various skill, attention, and ways of handling; who therefore cannot choose but
have different ideas of the same substance, and therefore make the signification of its common name very various
and uncertain. For the complex ideas of substances, being made up of such simple ones as are supposed to
co-exist in nature, every one has a right to put into his complex idea those qualities he has found to be united
together. For, though in the substance of gold one satisfies himself with colour and weight, yet another thinks
solubility in aqua regia as necessary to be joined with that colour in his idea of gold, as any one does its fusibility;
solubility in aqua regia being a quality as constantly joined with its colour and weight as fusibility or any other;
others put into it ductility or fixedness, etc., as they have been taught by tradition or experience. Who of all these
has established the right signification of the word, gold? Or who shall be the judge to determine? Each has his
standard in nature, which he appeals to, and with reason thinks he has the same right to put into his complex idea
signified by the word gold, those qualities, which, upon trial, he has found united; as another who has not so well
examined has to leave them out; or a third, who has made other trials, has to put in others. For the union in nature
of these qualities being the true ground of their union in one complex idea, who can say one of them has more
reason to be put in or left out than another? From hence it will unavoidably follow, that the complex ideas of
substances in men using the same names for them, will be very various, and so the significations of those names
very uncertain.
