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 man with two heads, or the upper parts of a man joined to
the body of a horse. I can consider the hand, the eye, the nose, each by
itself abstracted or separated from the rest of the body. But then
whatever hand or eye I imagine, it must have some particular shape and
colour. Likewise the idea of man that I frame to myself must be either of
a white, or a black, or a tawny, a straight, or a crooked, a tall, or a
low, or a middle-sized man. I cannot by any effort of thought conceive
the abstract idea above described. And it is equally impossible for me to
form the abstract idea of motion distinct from the body moving, and which
is neither swift nor slow, curvilinear nor rectilinear; and the like may
be said of all other abstract general ideas whatsoever. To be plain, I
own myself able to abstract IN ONE SENSE, as when I consider some
particular parts or qualities separated from others, with which, though
they are united in some object, yet it is possible they may really exist
without them. But I deny that I can abstract from one another, or
conceive separately, those qualities which it is impossible should exist
so separated; or that I can frame a general notion, by abstracting from
particulars in the manner aforesaid--which last are the two proper
acceptations of ABSTRACTION. And there are grounds to think most men will
acknowledge themselves to be in my case. The generality of men which are