Illusion and Truth

Illusion and truth are opposites, right?

But isn’t it the case that illusion is an integral part of true perception. The sofa across the room is no bigger than my thumbnail, and I can blot out the tree with my forefinger. If these objects appeared to me in their actual size, I could have no perception of their distance from me, their real distance. Given that we exist in space, illusion is a necessary aspect of every accurate perception. (Of course, it won’t do to solve this by saying that the sofa really is no bigger than my thumbnail, which would introduce a radical kind of relativism.)

Or, from another angle: I see only two sides of the pillar holding up the library ceiling. Given my angle of vision, I don’t even see those two sides fully. I never will be able to see all four sides at once without technical assistance (a system of mirrors would do it). Yet, if asked, I would describe the pillar as four-sided, and that each side is a rectangle equal in size to the others. This is an “illusion” within perception from the other side - that is, imagination supplies what, strictly speaking, visual perception cannot.