You are right, nobody has ever proven direct perception to be untrue. Neither have they ever proven the non-existence of God, or the non-existence of the animist's ''elan vital", the vital life force that is supposedly beyond mere biochemistry. However none of those are scientific hypotheses exactly because they are unfalsifiable. However it IS possible to show that visual experience is dependent on the causal chain, blocking any link of the chain disrupts the experience. That causal relation has never been disproven either, and it proves itself anew every time you blink your eyes. ALL the evidence favors a representationalist view, NONE supports the naive view, besides the naive realist illusion that it appears so.


My physicalism is reductive, in the sense that mind and brain are different aspects of the same basic underlying neurophysiological process, thus, the dimensions of conscious experience cannot possibly be greater than the dimensions of the corresponding neurophysiological state. If we see the world in the form of a 3-D "picture" of reality, then there are 3-D moving colored pictures in our brain, and what you see around you IS that picture in your brain.

This is the paradigmatic hypothesis, the initial assumption which is not itself ever proven, which lies at the core of the debate. My point is that the alternative, that there are 3-D moving colored pictures in our experience, but there are NO moving colored pictures in the brain, is positively anti-scientific, because that-which-is-to-be-explained, the explanandum, the 3-D colored pictures that define the puzzle of visual consciousness, are "explained away" as if they did not have real existence in the physical universe known to science. Whether like Max Velmans, you insist the images are projected out of the brain superimposed onto reality, or like the Behaviorists and J. J. Gibson, you simply refuse to discuss them at all, is immaterial. Like a magical disappearing act, you simply declare the explanandum to be undetectable in principle by physical means, and we can all go home, the problem is solved, the images don't exist in our brains, so don't even go looking for them in there. But they continue to exist in our experience! And they exist as 3-D pictures! And as I scientist, I insist that those pictures have real physical existence in the universe known to sciene, and the causal chain clearly indicates that they are generated in your brain! To claim otherwise is an extraordinary extra-scientific hypothesis that would require extraordinary evidence, to accept the notion that 3-D pictures can exist in our experience, but be undetectable in principle by physical means.

Your apparent bafflement at the relevance to this issue of the stupid automatic door-opener is indicative of your conceptual problem here. The photocell is a physical device. It cannot detect anything that does not impinge on it physically. There is no mystery to how light changes the voltage in the photocell, it is an ordinary causal reaction that can be easily followed back up the chain. A human viewing the entryway would be subject to the same causal limitations: breaking any link of the chain eliminates the experience of the scene that comes at the end of the chain. The causal dependence of experience on that chain of events is demonstrable and indisputable. To claim that this process is in any way 'direct' is a claim which is extraordinary, equivalent to claiming that the photocell detects a person in the entryway 'directly', not mediated by the beam of light that obviously triggers the photodetector, something that cam be demonstrated to be untrue.

To claim that perception is 'cognitively direct' despite every aspect of it being demonstrably indirect, is equivalent to claiming it is 'paradoxically direct', i.e. we know for a fact that it can't be direct, but we also "know" that it is direct anyway. The theory of "direct perception" is no different than the theory of "paradoxical perception", our visual system is obviously and demonstrably an indirect, representational system, our experience of the world is nevertheless paradoxically direct despite its demonstrable indirectness. That is what makes direct perception not a scientific hypothesis. Nor is it any kind of explanation to simply claim that the explanans, that which is to be explained, exists but is undetectable in principle so its existence cannot be demonstrated.

When the "obvious" explanation is blocked by chronic paradox, I say again: When the "obvious" explanation is blocked by chronic paradox, it is time to give serious consideration to the "incredible" alternative that the world you see around you IS the picture in your brain. Instead of trying to convince me how something indirect is actually direct, can you explain to me why you cannot possibly accept the fact that the world around you is a picture in your brain? Why is THAT notion so paradoxical to YOUR view that you'd rather accept a stark contradiction in its place? 

There is a peculiar asymmetry to this debate where I am required to prove that perception cannot be direct, when it has already been demonstrated again and again to be indirect, and yet nobody has ever, nor can ever possibly demonstrate how ANY ASPECT of perception can be direct.

This is evidence for the kind of paradigmatic debate where the naive view, which is plainly "obvious" to the common man, is challenged by a profoundly counterintuitive hypothesis which, however, addresses the profound paradoxes which are totally invisible to the naive observer. That is why this debate is always on "your terms", like debates with believers in God, where the burden of proof is always on the atheist to demonstrate that God does NOT exist, when there has never been the tiniest scrap of evidence for His existence. The one-sidedness of this debate reflects the paradigmatic schism in our world views. I can fully understand your position because I was there before, thats where I came from, we all begin as naive realists. But you cannot seem to bring yourself to consider that perception could be indirect, even as a theoretical possibility to be considered and rejected. Why is the burden not on YOU to demonstrate that representationalism is impossible in principle? Because until you do, it does remain the most plausible explanation for an eye that works like a camera, a retina like a photosensor array, an optic nerve like a data pipeline, and a cortex as an internal representation of external reality that is subject to transmission delays. Can you explain to me why that possibility is so improbable in your mind? 

How did you ever come to reject that hypothesis? What exactly was your reasoning?

Or have you ever really given it serious consideration as an actual possibility?