I may be mistaken, but I imagine that a major problem with early civilization is that night occurred.
Think about the problem of night-time.
From here on in, I am making stuff up, and have done no research. But think about it -- Darkness is a downer.
At some point in our earthly history, some Leno-jaw-boned guy surely started a fire with sticks and said "Holy shit" before either of those two words had meaning.
Now the problem was how to keep it going while you were not tending it. Hmmm… The idea of perpetual light must have been a…. near-orgasmic problem to be solved. Trust the Chinese….. the race that has had more orgasms than any other type of people! They took whale fat and constructed a device that would give light while you were severely worrying about darkness. One of them inserted a wick at some point. And candles were invented, thanks to this Chinese entrepeneur.
Milllennia later, an American guy [go figure] figured this "candle stuff" was not quite doing all it could do. Thomas Edison devised a light bulb. [Again, I am pretty much guessing here…. who cares what the guy's name was!]
Thing is, nowadays we do not at all worry about darkness. Unless it is voluntary. Or there is an electrical blackout. I can go down to my car right now, in an underground garage, and pretty much have a valid complaint if I cannot find my Mazda in the darkness.
We have come a long way from mistaking a stalactite in a cave for a stalagmite.
What are we even doing in a cave, without a flashlight, in the first place?
This is what I am saying.