Consider the case of an intelligence, or unbodied spirit, which is supposed to see perfectly well, i.e. to have a clear perception of the proper and immediate objects of sight, but to have no sense of touch.~ Let us now examine what proficiency such a one may be able to make in geometry...
First, then, it is certain the aforesaid intelligence could have no idea of a solid, or quantity of three dimensions, which followeth from its not having any idea of distance. We indeed are prone to think that we have by sight the ideas of space and solids, which ariseth from our imagining that we do, strictly speaking, see distance and some parts of an object at a greater distance than others; which have been demonstrated to be the effect of the experience we have had, what ideas of touch are connected with such and such ideas attending vision: but the intelligence here spoken of is supposed to have no experience of touch.~ Whence it is plain he can have no notion of those parts of geometry which relate to the mensuration of solids.~ Nor it is an easier matter for him to conceive the placing of one plain or angle on another, in order to prove their equality: Since that supposeth some idea of distance or external space. All which makes it evident our pure intelligence could never attain to know so much as the first elements of plain geometry.
Source: Berkeley: The Great Philosophers (The Great Philosophers Series) (Great Philosophers (Routledge (Firm))), Pages: 30..31
Contributed by: Chris