I'm of the opinion that in 500 years, we will look back upon the 1900s as holding four major innovations: - antibiotics - the fixation of atmospheric nitrogen

I'm of the opinion that in 500 years, we will look back upon the 1900s as holding four major innovations: - antibiotics - the fixation of atmospheric nitrogen into fertilizer / its precursors - the science of nuclear fission and the engineering of the nuclear chain reaction - the birth of computerized information processing and transfer Antibiotics solved so many otherwise-deadly or chronic diseases and opened the door to us doing pretty much any kind of intensive surgery. The Haber process is literally the source of 50% of the nitrogen in human tissue on Earth right now. Hunger is now "solved" in terms of the production side, and is a distribution problem. (It's somewhat amusing to me that people consider Malthus to have been an overconcerned worrywort - his concerns were prior to the invention of the Haber process and without it I think we would be having at least some problems, somewhere, with having enough fertilizer / sufficiently productive farmland. Long-term, there's no way nuclear fission and solar don't work together to be how humanity obtains its electricity. The economics are just too good. The sun is literally an enormous fusion reactor that costs nothing to operate, and between the amount of uranium we have and the ability of breeder reactors to convert non-fissile uranium into fissile uranium, coal can barely compete on the scale of hundreds of years. And of course the internet has put all of humanity on hyper-drive. Imagine if all of the the alchemists and natural philosophers of antiquity could just all text whenever they wanted to.