onsists of
parts is distinguishable into them, and what is distinguishable is
separable. But whatever we may imagine of the thing, the idea of a grain
of sand is not distinguishable, nor separable into twenty, much less
into a thousand, ten thousand, or an infinite number of different ideas.

It is the same case with the impressions of the senses as with the ideas
of the imagination. Put a spot of ink upon paper, fix your eye upon that
spot, and retire to such a distance, that, at last you lose sight of it;
it is plain, that the moment before it vanished the image or impression
was perfectly indivisible. It is not for want of rays of light striking
on our eyes, that the minute parts of distant bodies convey not any
sensible impression; but because they are removed beyond that distance,
at which their impressions were reduced to a minimum, and were incapable
of any farther diminution. A microscope or telescope, which renders them
visible, produces not any new rays of light, but only spreads those,
which always flowed from them; and by that means both gives parts to
impressions, which to the naked eye appear simple and uncompounded, and
advances to a minimum, what was formerly imperceptible.

We may hence discover the error of the common opinion, that the capacity
of the mind is limited on both sides, and that it is impossible for
the imagination to form an adequate idea, of what goes beyond a certain
degree of minuteness as well as of greatness. Nothing can be more
minute, than some ideas, which we form in the fancy; and images, which
appear to the senses; since there are ideas and images perfectly simple
and indivisible. The only defect of our senses is, that they give
us disproportioned images of things, and represent as minute and
uncompounded what is really great and composed of a vast number of
parts. This mistake we are not sensible of: but taking the impressions
of those minute objects, which appear to the senses, to be equal or
nearly equal to the objects, and finding by reason, that there are other
objects vastly more minute, we too hastily conclude, that these are
inferior to any idea of our imagination or impression of our senses.
This however is certain, that we can form ideas, which shall be no
greater than the smallest atom of the animal spirits of an insect a
thousand times less than a mite: And we ought rather to conclude, that
the difficulty lies in enlarging our conceptions so much as to form a
just no