That is not basic science. Randomized, double blind, placebo controlled trials are the gold standard of trials. Doesn't mean they're the only option. And, frank

That is not basic science. Randomized, double blind, placebo controlled trials are the gold standard of trials. Doesn't mean they're the only option. And, frankly, trials aren't that great as far as science goes. Physics seems to get by without them. And "prove"? What does that mean? (Big epistemology rabbit hole). I'll make the same point I did in my other comment more literally. I have a hypothesis that giving a 5k jog, three times a week to sedentary but otherwise healthy individuals will lower resting heart rate. I get my study population and randomize between treatment and control. Treatment does the running program for six weeks. Control does nothing. Treatment has a mean reduction in resting heart rate of 4 bpm. p = 0.01. n = 200. Have I proven anything? Do you think this was placebo? If it was debated if jogging reduced resting heart rate, was this study useful?