...the discipline of publicly testing ideas by systematic observation, controlled experiment, and Bayesian inference.
Science is not a "method". Feyrabend was more nearly right than he realized when he said the cardinal rule of science is, "Anything goes": we can use any clever tricks that pass the tests to change the posterior plausibility of an idea, and they do not have to adhere to some philosopher's notions of method.
Science is a discipline, and like any other discipline has to be practiced to get good at it. Methods in science are like katas in fighting disciplines: valuable training devices, but not anything like sufficient to win a real fight.
Furthermore, as a discipline, science does not explain anything and has no content: the sciences (biology, physics, geology...) do, but not the overarching discipline of science itself.
The discipline of science can be practiced by anyone, although history has shown that education can help (try inventing any fighting discipline on your own and you'll see how much better off you'd be learning from someone else.) The scope of science is unlimited, and it is the only way of creating knowledge. It is not "scientism" to practice the discipline of science when testing ideas about human behaviour or society: it is just science.
Because science is Bayesian, it does not produce certainty. Bayes' rule cannot generate a plausibility of 0 or 1 for any proposition, and it identifies anyone who assigns a plausibility of 0 or 1 as being in a state of sin... err... error.
A proposition that has 0 or 1 plausibility cannot have its plausibility changed by further applications of Bayes rule, so it is beyond correction, opaque to any further evidence, cut off from the world it claims to apply to.
The technical term for a belief held in such an erroneous fashion is "faith".