upon shutting them again, and
considering the distance betwixt these bodies, I acquire the idea of
extension. As every idea is derived from some impression, which
is exactly similar to it, the impressions similar to this idea of
extension, must either be some sensations derived from the sight, or
some internal impressions arising from these sensations.

Our internal impressions are our passions, emotions, desires and
aversions; none of which, I believe, will ever be asserted to be the
model, from which the idea of space is derived. There remains therefore
nothing but the senses, which can convey to us this original impression.
Now what impression do oar senses here convey to us? This is the
principal question, and decides without appeal concerning the nature of
the idea.

The table before me is alone sufficient by its view to give me the idea
of extension. This idea, then, is borrowed from, and represents some
impression, which this moment appears to the senses. But my senses
convey to me only the impressions of coloured points, disposed in a
certain manner. If the eye is sensible of any thing farther, I desire
it may be pointed out to me. But if it be impossible to shew any thing
farther, we may conclude with certainty, that the idea of extension is
nothing but a copy of these coloured points, and of the manner of their
appearance.

Suppose that in the extended object, or composition of coloured points,
from which we first received the idea of extension, the points were of
a purple colour; it follows, that in every repetition of that idea we
would not only place the points in the same order with respect to each
other, but also bestow on them that precise colour, with which alone we
are acquainted. But afterwards having experience of the other colours of
violet, green, red, white, black, and of all the different compositions
of these, and finding a resemblance in the disposition of coloured
points, of which they are composed, we omit the peculiarities of
colour, as far as possible, and found an abstract idea merely on that
disposition of points, or manner of appearance, in which they agree. Nay
even when the resemblance is carryed beyond the objects of one sense,
and the impressions of touch are found to be Similar to those of sight
in the disposition of their parts; this does not hinder the abstract
idea from representing both, upon account of their resemblance. All
abstract ideas are really nothing but particular o