137. Visible figure and extension having been demonstrated to be of a
nature entirely different and heterogeneous from tangible figure and
extension, it remains that we inquire concerning. Now that visible motion
is not of the same sort with tangible motion seems to need no farther
proof, it being an evident corollary from what we have shown concerning
the difference there is between visible and tangible extension: but for a
more full and express proof hereof we need only observe that one who had
not yet experienced vision would not at first sight know motion. Whence
it clearly follows that motion perceivable by sight is of a sort distinct
from motion perceivable by touch. The antecedent I prove thus: by touch
he could not perceive any motion but what was up or down, to the right or
left, nearer or farther from him; besides these and their several
varieties or complications, it is impossible he should have any idea of
motion. He would not therefore think anything to be motion, or give the
name motion to any idea which he could not range under some or other of
those particular kinds thereof. But from sect. 95 it is plain that by the
mere act of vision he could not know motion upwards or downwards, to the
right or left, or in any other possible direction. From which I conclude
he would not know motion at all at first sight. As for the idea of motion
in abstract, I shall not waste paper about it, but leave it to my reader
to make the best he can of it. To me it is perfectly unintelligible.

138. The consideration of motion may furnish a new field for inquiry: but
since the manner wherein the mind apprehends by sight the motion of
tangible objects, with the various degrees thereof, may be easily
collected from what hath been said concerning the manner wherein that
sense doth suggest their various distances, magnitudes, and situations, I
shall not enlarge any farther on this subject, but proceed to consider
what may be alleged, with greatest appearance of reason, against the
proposition we have shown to be true. For where there is so much