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How Secondary.       §13. After the same manner, that the Ideas of these original
Qualities are produced in us, we may conceive, that the Ideas of
secondary Qualities are also produced, viz. by the operation of insensible
particles on our Senses. For it being manifest, that there are Bodies,
and good store of Bodies, each whereof is so small, that we cannot,
by any of our Senses, discover either their bulk, figure, or motion, as
is evident in the Particles of the Air and Water, and other extremely
smaller than those, perhaps, as much smaller than the Particles of
Air, or Water, as the Particles of Air or Water, are smaller than
Pease or Hail-stones. Let us suppose at present, that the different
Motions and Figures, Bulk, and Number of such Particles, affecting
the several Organs of our Senses, produce in us those different
Sensations, which we have from the Colours and Smells of Bodies,
v.g. that a Violet, by the impulse of such insensible particles of
matter of peculiar figures, and bulks, and in different degrees and
modifications of their Motions, causes the Ideas of the blue Colour,
and sweet Scent of that Flower to be produced in our Minds. It
being no more impossible, to conceive, that God should annex such
Ideas to such Motions, with which they have no similitude; than
that he should annex the Idea of Pain to the motion of a piece of
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Steel dividing our Flesh, with which that Idea hath no resem-
blance.
Locke Hum II, 8, §13, pp. 136-137