Or sit in a dark room, unable to see anything. There is more to it. See, e.g., https://en.m.wikipedia.org/wiki/Emission_theory_(vision)
I guess they could have argued that the rays of light returning from each object were perfect specular reflections that traveled directly back to the eyes that emitted them... but wow, that's still pretty hard to fathom, even for people who never heard of Occam's Razor.