Wikipedia is not a valid source...period. However, it is good for generalized information to a degree. This piece on randomized trials, single-, double-, and triple-blind tests, is actually pretty accurate. I suggest anyone interested read this to get an idea of what we have to go through to prove something. Oh wait, no, proofs are for math, in science we CAN NEVER PROVE ANYTHING! We only show that with a certain level of confidence, what we have found is very likely to be the truth as we understand it (usually 95% certain and do not ask me to explain).