The Intromissive Theory of Vision

In the ancient world, they had a variety of theories about how vision works. Isaac Newton thought that light is made out of tiny particles and so he invented what's called the corpuscular theory of light. But Christian Huygens pointed to evidence that suggested light is a way. The wave theorists then said, Oh, well, have we got news for you? Going back to the ancient Greeks, there's this concept that space is made from ether.