Going further, all of those are currently under the umbrella of metaphysics, which is again a kind of prejudiced-against (often taken as irrelevant, when it contains some of, and in fact many of, the most important things in life) field of science/knowledge. I think metaphysics should just be seen for what it is as a more indirect kind of science. In a way all of science is varying degrees of indirect, we use all sorts of instruments and need to make all kinds of assumptions (that conceivably, but unlikely, could indeed be false) to be able to do any kind of science or assume any kind of validity to results. We need to assume (although indeed many of those assumptions we don't even need to consider, i.e. they're implicit) there aren't any "gremlins" of whatever kind interfering with our measurements. We do our best to cross-verify whatever experiments we have to increase our confidence. Likewise, metaphysics to me is simply about inferring facts and properties with more indirect methods. One of them is what I referred to above, i.e. observations from within your own mind, and proposing properties of cognition from first hand experience. A second (very close to actual physics) is conjecturing what other universes are out there of if there is some larger mechanism our own universe (or all universes) are part of. Another is judging other properties of existence, for example, are our minds completely separate or are we all ultimately part of the "same thing", somehow? How did I come about living as the person I am currently living, am I perhaps a random sample, with some particular distribution, of all living beings? How do those facts influences how we should live together? (I think they all strongly support the notion of valuing everyone, and discredit any absolute notion of primacy of yourself in ethics, i.e. egotism).