. For example, the mind
having observed that Peter, James, and John resemble each other
in certain common agreements of shape and other qualities, leaves
out of the complex or compounded idea it has of Peter, James, and
any other particular man, that which is peculiar to each, retaining
only what is common to all, and so makes an abstract idea wherein
all the particulars equally partake--abstracting entirely from
and cutting off all those circumstances and differences which might
determine it to any particular existence. And after this manner it is
said we come by the abstract idea of MAN, or, if you please, humanity, or
human nature; wherein it is true there is included colour, because there
is no man but has some colour, but then it can be neither white, nor
black, nor any particular colour, because there is no one particular
colour wherein all men partake. So likewise there is included stature,
but then it is neither tall stature, nor low stature, nor yet middle
stature, but something abstracted from all these. And so of the rest.
Moreover, their being a great variety of other creatures that partake in
some parts, but not all, of the complex idea of MAN, the mind, leaving
out those parts which are peculiar to men, and retaining those only which
are common to all the living creatures, frames the idea of ANIMAL, which
abstracts not only from all particular men, but also all birds, beasts,
fishes, and insects. The constituent parts of the abstract idea of animal
are body, life, sense, and spontaneous motion. By BODY is meant body
without any particular shape or figure, there being no one shape or
figure common to all animals, without covering, either of hair, or
feathers, or scales, &c., nor yet naked: hair, feathers, scales, and
nakedness being the distinguishing properties of particular animals, and
for that reason left out of the ABSTRACT IDEA. Upon the same account the
spontaneous motion must be neither walking, nor flying, nor creeping; it
is nevertheless a motion, but what that motion is it is not easy to
conceive[Note.].

[Note: Vide Hobbes' Tripos, ch. v. sect. 6.]

10. TWO OBJECTIONS TO THE EXISTENCE OF ABSTRACT IDEAS.--Whether
others have this wonderful faculty of ABSTRACTING THEIR IDEAS,
they best can tell: for myself, I find indeed I have a faculty of
imagining, or representing to myself, the ideas of those particular
things I have perceived, and of variously compounding and dividing them.
I can imagine a