'See-through' things (glass, water, plastics, etc) are not actually see-through. @dukkha I think you asked the same thoughtless question back on the old PF, and I seem to remember responding to it. I say thoughtless, because I can't imagine how you can be so stuck on this for years unless you have simply stopped thinking.
Surely you don't think that when you look in a mirror, you are *literally* seeing your own face, as if the mirror magically turns the direction of your gaze back towards you? — dukkha
Although I agree with Andrew that "literally" doesn't really belong here, nonetheless I
would affirm, if specifically asked, that I am literally seeing my own face in the mirror. I'm seeing it indirectly, perhaps--but this is the only way I can see it anyway.
Or even just look through your windscreen, and then stick your head out your window and look at the road directly. They don't look exactly the same, in fact there's quite a few difference go check for yourself. How do you explain this if in both cases you're seeing the same road, if the windscreen is 'see-through'? — dukkha
To see through something is often to see it distorted. What do you think "see-through" means? If you think to be see-through is to be non-distorting, then you just don't know what it means.
Treating the light reflected off the object geometrically, one can make a cross-section anywhere along the path from object to eye. One can then stipulate that this cross-section is a projection or image. All you're doing is making your cross-section at the pane of glass, imagining it as an image, and then treating this image as the thing that is seen. You could equally take a cross-section in mid-air as the image that is seen, if that's the way you want to use the word "see". But it's arbitrary and says nothing profound. But it's actually much worse than that, because when you say that this imaginary image is what is
seen, you are misusing the word "see" and causing yourself untold confusion.