It keeps happening everytime I go on a bikeride, I find myself thinking "The bicycle is the greatest invention in the history of the world." Then I think that it must be the wheel. Then I think that the wheel isn't really an invention as it can be readily obtained by rolling a log down a hill. Kind of like the bridge can't really count as an invention because it readily apparent in a log fallen across a river. SO language isnt an invention but the alphabet is? Now the question is bit more complicated than my initial euphoric nomination.
Greatest invention needs some categories. Transportation (bicycle, boat, sail, internal combustion engine, jet ski) Communication (alphabet, pencil, paper, movable type, radio, TV, computer) Food production (shovel, plow, tractor, insecticide) Weaponry (knife, bow and arrow, musket, repeating rifle, A-bomb). Maybe categories like this will help us sift out the rightest answer.
Then it becomes clear pretty quickly that we have a serious issue of constituent parts. The bicycle is actually a specific combination of a bunch of inventions-- gears, brakes, rubber tires, water bottle holder. Perhaps this distinction will help us figure out the greatest invention in world history. With all the carnage and corruption that is daily documented here maybe we can take a break and cast our eyes on the amazing things us humans have made and done on this earth. I'd like to motion that we consider inventions that are still in wide use today.
I'm going with my gut here. The greatest in world history is the bicycle. It's practical and fun. The fuel is your own energy. Okay it didnt result in a cultural revolution like some inventions, but I want to nominate it. Go ahead, tell me why I'm wrong. I want to know, if not the bike, then what-- and why? I know it'll be something so ubiquitous that I've taken it for granted.