the things themselves be certainly
discovered; in which consists perfect knowledge. Nor let any one object,
that the names of substances are often to be made use of in morality,
as well as those of modes, from which will arise obscurity. For, as to
substances, when concerned in moral discourses, their divers natures
are not so much inquired into as supposed: v.g. when we say that man
is subject to law, we mean nothing by man but a corporeal rational
creature: what the real essence or other qualities of that creature are
in this case is no way considered. And, therefore, whether a child or
changeling be a man, in a physical sense, may amongst the naturalists be
as disputable as it will, it concerns not at all the moral man, as I
may call him, which is this immovable, unchangeable idea, a corporeal
rational being. For, were there a monkey, or any other creature, to be
found that had the use of reason to such a degree, as to be able to
understand general signs, and to deduce consequences about general
ideas, he would no doubt be subject to law, and in that sense be a MAN,
how much soever he differed in shape from others of that name. The names
of substances, if they be used in them as they should, can no more
disturb moral than they do mathematical discourses; where, if the
mathematician speaks of a cube or globe of gold, or of any other body,
he has his clear, settled idea, which varies not, though it may by
mistake be applied to a particular body to which it belongs not.

17. Definitions can make moral Discourse clear.

This I have here mentioned, by the by, to show of what consequence it is
for men, in their names of mixed modes, and consequently in all their
moral discourses, to define their words when there is occasion: since
thereby moral knowledge may be brought to so great clearness and
certainty. And it must be great want of ingenuousness (to say no worse
of it) to refuse to do it: since a definition is the only way whereby
the precise meaning of moral words can be known; and yet a way whereby
their meaning may be known certainly, and without leaving any room for
any contest about it. And therefore the negligence or perverseness of
mankind cannot be excused, if their discourses in morality be not much
more clear than those in natural philosophy: since they are about ideas
in the mind, which are none of them false or disproportionate; they
having no external beings for the archetypes which they are referred to
a