How can anybody, including myself, be sure that what is seen is real? My right eye was scratched, and I can see this scratch-mark before "reality", as one would see their right hand before their left if they arranged the two that way. I wonder if this proves the external to be an actual place within something (the universe?), like it has an absolute position within my (a sentient being) perception. This brings me to my final question: How can I prove the distance between my two hands? When I look at my right hand in front of my left hand, I see them as two objects apart from each other, but I sometimes see a flat picture, like a movie screen: it is manifestly flat but produces 3-dimensional pictures. Does this mean that my eyes create reality to be other than what it is, like how they create depth to be where it really is not? Or does this mean that my eyes are perceiving reality as it should be perceived? Ugh! And the thought that those who cannot "see things" in ink-blots on white paper have learning disabilities peeves me. They should be proud that their minds do not create fallacies! That is what I think.

Yeah, these are the kinds of questions that lead many of us to "Argggh!" They're also the kind of questions that I approach with a great deal of trepidation because they are knottier than knotty. So, please understand that what I say here by the nature of this kind of exposition will be very rough and overly simplistic. You'll also probably find more than a few of my colleauges to disagree. But anyway, let's barrel right on with it.

I don't think you can be absolutely sure that what you see is what's "real"--though you really ought to take some time to parse out what you mean by that word because it's LOADED. I take it that you mean by "real" something like what's out there independently of us. In a sense, actually, my best shot is that what you or we see isn't exactly real in that sense. Do remember that old Aristotelian question, "When a tree falls in the forest and there's no one around to listen, does it make a sound?" Well . . . get ready . . . almost yes, but no. No in the way that it's not precisely right even to talk about "trees" and "forests" existing independently of us. Before you call for an ambulance to pick me up, what I mean by that crazy sentence is that what we experience is a kind of product of a number of factors, roughly our perceptual faculties and what seems to exist independently of us and interacts with them. The sound of a tree falling, for example, is the product of (1) our sense of hearing and (2) something like sound waves. Without either of these factors there's no sound. (If you think about it, this is actually obvious. Just ask any deaf person, or go into a silent room.) We contribute some of what goes into experience, and the external stuff contributes some of it. That goes for all the other dimensions of our experience of a tree falling or just a tree. Since in this sense there is no "sound" without the hearing of sound, then it really isn't meaningful to ask whether the sound we hear is the same as the sound that's out there. You see, there is no sound out there. Sound, like every other perceptual experience, exists in the relationship the relationship between us and what's not us. (Actually, I shouldn't even say "us"; but let's just let that slide.) No objects of experience strictly speaking exist out there. Now, it doesn't follow from this that nothing exists beyond us. I think there are pretty convincing, if not absolutely convincing, reasons to think so--at least I'm convinced. The shorthand way I'd put it is that the world we experience is external reality as it appears to us through its interactions with us. (And we are what we experience of us in the course of that interaction--there, I've said it.)

About your eye, I'd say you interpret what you see as a scratch, and your interpretation works better than others. So, go with it.

About whether we experience reality the way it "should" be experienced. I don't think there's any way reality "should be perceived". It just is perceived, and we make the best of it we can.

About "proving" the distance between your hands, I'm not sure what you mean. Once you've accepted hands and distance as meaningful, once you're in that relationship, you pick up (or have someone else pick up) a measuring tape and measure.

About seeing three dimensinal pictures at the movies, I'd say you see two-dimensional pictures that you full well know are two-dimensional and interpret them or imagine them as representations of three-dimensional things. You don't really think of them as three-dimensional; otherwise you'd duck when someone shot towards the screen or a robot exploded, or something.

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