But it did not, at that time, seem to me doubtful that, if there are two patches of red in two different places, there are two particular reds. The necessity of thinking them two was bound up with the relativity of position: the two patches, I thought, differ only in position, and since position is not a quality (or so I thought), it presupposes diversity and cannot constitute it. With the recognition that position in space is absolute, the situation changed. A red patch on my right can be a complex of the two qualities redness and rightness; and a patch on my left can be a complex of the two qualities redness and leftness. Right and left, as well as up and down, have, in all their various degrees, the logical characteristics which are required for geometry, and it is their union with some one quality, such as redness, which gives plurality to two patches of redness seen simultaneously.
(Bertrand Russell, My Philosophical Development, ch. 14)