20. Ideas of the leading qualities of substances are best got by showing.
These leading sensible qualities are those
which make the chief ingredients of our specific ideas, and consequently the most observable and invariable part
in the definitions of our specific names, as attributed to sorts of substances coming under our knowledge. For
though the sound man, in its own nature, be as apt to signify a complex idea made up of animality and rationality,
united in the same subject, as to signify any other combination; yet, used as a mark to stand for a sort of creatures
we count of our own kind, perhaps the outward shape is as necessary to be taken into our complex idea, signified
by the word man, as any other we find in it: and therefore, why Plato's animal implume bipes latis unguibus
should not be a good definition of the name man, standing for that sort of creatures, will not be easy to show: for
it is the shape, as the leading quality, that seems more to determine that species, than a faculty of reasoning, which
appears not at first, and in some never. And if this be not allowed to be so, I do not know how they can be excused
from murder who kill monstrous births, (as we call them), because of an unordinary shape, without knowing
whether they have a rational soul or no; which can be no more discerned in a well-formed than ill-shaped infant,
as soon as born. And who is it has informed us that a rational soul can inhabit no tenement, unless it has just such
a sort of frontispiece; or can join itself to, and inform no sort of body, but one that is just of such an outward
structure?
