As the natural light outdoors fades, a mundane miracle occurs. Tho I have no supernatural powers, I create light and see that it is good. There is much to celebrate in the simple act of flipping a switch, and the resulting light provides many other mundane miracles to ponder.
Before I close the curtains, a pine tree across the lawn is still visible thru the window. Conversely, a bird roosting in the pine could see the light fixture I have just turned on. Most of the light that my fixture throws toward the window goes right thru the glass, harmless and unharmed. My fist could not do that.
It gets better.
Some of the light that hits the window is reflected back. I see my fixture as a ghostly sphere, apparently hovering between me and the pine. Hmmm. Consider a single photon among the zillions that whiz from my fixture toward the window. How does it decide whether to continue on toward the pine or bounce back toward me?
I know. Photons are mindless particles that do not decide anything. They just do whatever a divinely perfect knowledge of physics would say they do, and a humanly possible imperfect knowledge of physics is rather good at saying what big groups of them do.
By far the best current human knowledge says that what a single photon does is unpredictable. Not just unpredictable because we do not know all the details about the laws of nature or how the photon is moving or what is in the glass where the photon hits it. Not just unpredictable because exact calculations are not feasible. Intrinsically unpredictable! On a photon-by-photon basis, even divinely perfect knowledge of the rules and the current situation does not determine what will happen in the next picosecond. Even God must wait and see.
Dunno whether I will succeed in posting more about intrinsic unpredictability and its consequences. (Don’t hold your breath.) Without wrangling equations, a great deal can be still be said about the quantum physics behind partially reflected light and its wider implications. See pages 173-176 of the excellent book Dice World by Brian Clegg (or web pages like the one U can visit by clicking here, if U do not have the book handy).