Ralph Waldo Emerson, answered from the texts and cited to the page.
The transparent eyeball — that is the name I gave to an experience, not to a doctrine, and the difference matters. It appears in Nature, in the chapter on "Idealism," and it names the moment when the self that ordinarily stands between a man and the world is annihilated, and he becomes nothing but a vessel for seeing. I wrote of crossing a bare common in snow puddles at twilight, and of how, in that moment, I became a transparent eyeball — I am nothing, I see all, the currents of the Universal Being circulate through me.
The grammar of that sentence is the experience: the I dissolves, and what remains is pure receptive vision, which turns out to be the same as the whole. What the passage before us in Nature illuminates is the preparation for that moment. The Reason, stimulated to more earnest vision, sees through outlines and surfaces to causes and spirits; the material world goes transparent, and what had seemed solid becomes the symbol of something behind it.1
The best moments of life are these awakenings of the higher powers, these instants when nature withdraws reverentially before its God.2 The mechanical hints nature gives us point the same way. A slight shift in position — seeing a familiar shore from a moving ship, or looking at a landscape through your legs — detaches the scene from all its ordinary relations and gives the whole world a pictorial air.3
The earnest mechanic and the lounger and the boys in the street become unrealized, apparent rather than substantial.4 What such tricks of position teach is that something in the observer is stable while the spectacle shifts — that man and nature are not one continuous substance but stand in a relation of beholder to beheld.5 The transparent eyeball is the limit of that discovery: push it to its extreme, and the stable something in the observer is no longer a private self at all.
It is the impersonal soul, the Over-Soul, seeing through the aperture of this particular body. I am nothing — the personal Emerson, with his opinions and his history — and I see all, because the seeing is not mine but the universe's own self-regard. That is why the experience carries awe alongside pleasure: a man is apprised, in that moment, that while the world is spectacle, what in him beholds it is not bounded by him.5
If the Reason be stimulated to more earnest vision, outlines and surfaces become transparent, and are no longer seen; causes and spirits are seen through them.Nature, Addresses, and Lectures
The best moments of life are these delicious awakenings of the higher powers, and the reverential withdrawing of nature before its God.Nature, Addresses, and Lectures
The last change in our point of view, gives the whole world a pictorial air.Nature, Addresses, and Lectures
The men, the women,--talking, running, bartering, fighting,--the earnest mechanic, the lounger, the beggar, the boys, the dogs, are unrealized at once, or, at least, wholly detached from all relation to the observer, and seen as apparent, not substantial beings.Nature, Addresses, and Lectures
Hence arises a pleasure mixed with awe; I may say, a low degree of the sublime is felt from the fact, probably, that man is hereby apprized, that, whilst the world is a spectacle, something in himself is stable.Nature, Addresses, and Lectures