Some of the most interesting discussions in science concern the limits of scientific knowledge. There is the issue of whether or not science can answer questions about God, or definitively rule out supernatural causes. In addition to these big questions, I am also quite interested in the limitations of specific theories or studies. I believe it is more important, and more useful, to be able to evaluate the second type of limitation than to be able to participate in high minded philosophical discussions about science.
It is often easy to over interpret a particular theory or experimental finding, and to extend its implications beyond what the evidence really supports. You see this a lot with quantum mechanics. QM describes the behavior and properties of matter at the atomic scale, but many of its core truths do not hold up at larger scales, for example in the "real" world that we experience every day. We are made up of atoms, and it is not as though there is no connection between quantum and classical physics, but my (admittedly limited) understanding is that physicists have not yet worked out how it all fits together.
I'm engaged in an ongoing discussion with an acquaintance via Facebook messages, and he asked me whether I thought it was possible that a recent experience of his could be explained by alternate realities, and he made an appeal to quantum mechanics. I suggested we reframe the question to ask whether QM has anything relevant to say about his experience. I believe it does not. QM says a lot of strange things, for example that an electron can be in two places at once, but I think the majority of physicists would say that this does not mean that a human being or a stack of books can simultaneously occupy two distinct positions. As for souls or consciousness, physics does not currently define these entities. Assigning physical properties to them-quantum or otherwise-requires making some major assumptions. I told my friend I did not think it was "wrong" to have QM-inspired metaphysical beliefs, but stating that QM supports such beliefs would be incorrect. I'm not sure that QM refutes his beliefs either; rather, I think that the ideas he expressed lie outside the quantum realm altogether, at least in terms of current theory.
(I'm using the
bad science tag not to be critical, but because I think this is a common flaw in scientific, or science-inspired, thinking.)