I was watching a show called 101 Gadgets that changed the world. They had Edison's light bulb as one of them. My thought is when somebody comes up with an idea they get a light bulb over their head. What popped up over Edison's head when he got the idea of the light bulb?
If Edison got a candle/lamp over his head, did the inventor of those get a caveman fire over their head? What did the cavemen get over their head when they were discovering fire? Oh boy, am I thinking about this too much?