Every time someone puts "scientific method" I get this image of a framed poster detailing the scientific method in a hallway in a house that gets walked by frequently where the owner always winks or salutes or just bursts into a big smile.
In the grandiose philosophical choice (where scientific method resides), I'd go with either writing or higher education. No society had settled into the modern low fertility/low mortality pattern until enough individuals could write or use their higher education to invent things that made death less likely (mortality rate drop). With death less likely and with more inventions to purchase/consume, you didn't need as many humans gobbling up increasingly expensive resources and women as a result had fewer children. In other words, the demographic transition that allows such high proportions of our lives to be spent on leisure was brought about by writing/higher education (by many things in reality but I think this is the big one, watch an underprivileged country/area enable women easier access to higher education and watch what happens over the next 10-20 years).
For the more tangible inventions, I think of 2 main categories:
-inventions that heighten/enhance or make basic human functions a reality/tolerable/more fair e.g. enchroma glasses for those with total color blindness, Viagra, vibrator, RU-486, morphine, alcohol, toilet paper, light bulb, etc.
-inventions that increase our ability to recreate e.g. violin, football, tennis shoes, paintbrush, hydration pack, roller coaster, deck of cards
