Gravity is proved. Evolution is rock solid. We still don't know if coffee is good or bad for us. Gravity is not proven. Falling is easily observed, and general

Gravity is proved. Evolution is rock solid. We still don't know if coffee is good or bad for us. Gravity is not proven. Falling is easily observed, and general relativity is a pretty good theory for it, but the jury is still out on how exactly gravity works. Evolution is also easily observed (e.g., drug resistant pathogens); its basis in natural selection and genetics is the part that is rock solid. As for coffee, it's some combination of good and bad. Which part dominates in which situations is up for debate. (Apologies for being pedantic -- caffeine high just set in.)