Concepts explained
Why the Apple Is Red — We Have Never Seen an Object
The apple is red because it threw red away. And what reaches your eye is not even the light that struck it — it is light the apple has just made and flung back.
from the lamp travels to the apple. That light has red, orange, yellow, green and blue all mixed into it. White light is mixed to begin with.
The apple swallows most of them. Green, blue, all swallowed and turned into a very faint warmth inside the fruit. Red alone it cannot swallow, so it spits it back out.
That rejected red is what enters your eye.
The light that leaves is not the light that arrived
It gets stranger. The light the apple spits out is not the light that struck it.
The incoming light ends there. A tiny particle at the surface takes it, shivers, and in shivering makes a new one and sends that out. What arrives and what departs are different individuals.
So we believe we are looking at an apple, when we are looking at light the apple has just manufactured and thrown. Slightly late, at that.
The same holds for this screen, the back of your hand, the tree outside. We have never seen an object. We have only ever seen what objects spat back.
A thousand years ago it was understood the other way round: light left the eye and groped for things, as if the eye were a torch. Until a man in Cairo bored a small hole into a dark room and showed that the world outside lands upside down on the wall while the eye does nothing at all.
The question that remainsIf what we see is never the object but only what it spat back, is the apple in an empty room still red?