how i experience "visualization" versus "seeing"
this struck me as a useful way of explaining the difference between mental imagery and sight for people who don't form mental images.
when i "imagine an apple", a few things come to mind. i get a general visual gestalt of an apple with certain visual qualities (e.g. it's green); i get a detailed "zoom-in" of a small part of the apple's surface including things like texture, beads of moisture, shine; and if it occurs to me to think about about these things i can imagine the sound of someone biting the apple or the texture of one of those really unpleasant mealy apples. these things have sensory "quality" but not "presence", i.e. there's no floating apple blocking out my visual field. my visual field only contains things that i'm seeing.
the main thing is—because none of this is happening in the visual field and isn't related to "sight" from the eyes—i experience all of the above at the same time or in rapid succession. it doesn't really compose or play out like a scene or a static "image" so much as a fluctuating network of sensory impressions, of which any one can be hard for me to isolate or focus on. to me, this is one of the most fundamental ways "visualization" is not like sight.