@Verus:
But to know that, we would need to know the rules.
In case of lack knowledge, intuition comes into play.
And even then, I would argue that those internal inconistencies exist.
I just wrote some huge goddamned post then accidentally backed out. I am now going to furiously attempt to recreate it to some accuracy. Ugh.
Point 1: Physics of One Piece and of our world, as enterprises, share a structure, but can diverge widely in contents. Physics is an empirical enterprise that aims to make sense of the world by starting with our experiences of the world and then consistently proceeding through logic to (usually, but not always, testable) hypotheses that explain that world. Insofar as some physical theory fails to explain the world, so much the worse for the theory; the world is whatever way it is, and our failure to explain it does not fundamentally change whatever way the world may happen to be.
The One Piece world is a different world than ours, and so a science of physics of the One Piece world would need to explain different phenomena than our own physics. It has to explain how that world works, and thus must explain a very different world than our own. In our own world, as in the One Piece world, physics does not "start" with rules - rules are not first given, as if we ought test our observations by the rules, and dismiss the world wherever it does not align with our dogma. It starts with the world, and our rules are derived by trying to understand that world. Since physics in One Piece and in the real world have very different worlds as their targets, there is absolutely no good reason why One Piece physics - laws, mechanisms, ontological furniture… - must coincide with our own. What they do have in common is a system for explaining their respective and distinct worlds.
In other words: Physics is not universal across all possible worlds but is localized to worlds in which we find ourselves. Physics must answer to the world it is a physics of, and not to any other world. (Relating to an earlier post I made and an objection to that post, this is why metaphysics is important and is - arguably - what we are doing whenever we try to do "physics" of a universe that is not our own. We'll see shortly that, since we cannot experiment in worlds not our own, we must there rely on logical possibility and necessity, and on speculation from the world in question; in an important sense, this is closer to metaphysics than to physics, except insofar as metaphysics often attempts to make no reference to any particular world. In large part Point 1 can be seen as a partial response to that original objection that one piece world physics diverges in content from real world physics: of course it diverges, as it is physics of a different world. I do not remember the details of the original objection, and I am do not believe I have here expressed fully an adequate response to it.)
Point 2: Physics (and philosophy and science generally) can diverge greatly from common sense or intuition.
Stipulation: For my purposes, I am going to define intuition as common sense or common perception. There are other possible definitions, and I think what I say will work for many, but probably not all, definitions of intuition.
This point is straightforward. We do not consciously experience anything like quarks, yet we theorize about quarks in order to explain the world that we do consciously experience. Such theorizing often has explanatory power far surpassing common sense or "intuitive" explanations of the world, and also often diverges from them. One goal in physical theory is to explain the world in a logically and empirically consistent way. But, to common perception and common sense, the world does not always seem consistent - it can seem mysterious sometimes, and at other times we may even experience apparently contradictory phenomena. Physics promises that, once we see the world at the right level, these inconsistencies drop out. Insofar as physics provides a more consistent and explanatory theory than does common sense or intuition, so much the worse for common sense and intuition.
Disclaimer: This is actually a very nuanced position. I do not think these nuances matter here, but I also cannot in good faith pretend that science is an end all/be all take on the world. Again, this doesn't here matter, since I am just looking at the methodology of the common conception of physics - it is up to you to decide whether or not this plausible conception of physics is a valuable or authoritative one.
By these two points, we can draw two conclusions:
(1) One Piece Physics need not converge in contents with our own Physics. They are both "physics" only insofar as they are enterprises of explaining their respective worlds.
(2) Physics, in the real world or in One Piece, is not a matter of common sense, but rather one of consistently and in a logically coherent way explaining some world. (Once we move away from our own actual world, we begin to do a king of metaphysics rather than a strict physics.)
So, I disagree that we need to know the rules ahead of time or that we must rely on intuition when we don't; in real physics, we do not know the rules ahead of time, and we do not rely on intuition when we don't. Physics is answerable to logic and to the world as we observe it. (If by intuition you mean the world as observed then you are right, but it seems a less interesting point - no offense).
So, the issue is not comparison to our world, but is this: Is the one piece world internally consistent or not? In other words, can we consistently explain the happenings of the One Piece world?
There are some nuances and guidelines here.
First: In the real world, everything actual is possible - only things that can happen do happen. In a fictional world, this is precisely what is at stake - we want to show that, given the totality of the one piece world, some happenings are incompatible with one another or inconsistent with the rest of the world generally, or that neither of these is the case and it's "all good." Examples can be useful here. On the flip side, we ought try to explain seemingly contradictory phenomena in one piece in exactly the same way as we do in real world physics, and common sense or intuition is not a boundary to real world physics and so should not be considered a boundary to one piece physics; we need only be bound by what we observe of the world itself and by logical relations (since logic is, according to most but not all, "universal"; if it is not, then we first have to develop a one piece logic, and that is a far more daunting task…).
Second: In the real world we can test many of our hypotheses; since we are not part of the OP world, we cannot perform OP world experiments. What we can do, however, is observe the happenings of the world as they occur, and dismiss any theory which does not adequately explain those happenings. We must, in performing physics, always strive ultimately to explaining the world as it seems to be.
So, you're absolutely right about your last point: Internal Inconsistencies are key. We must try to resolve internal inconsistencies, but in doing so we must appeal to logic and to the one piece world itself, not to our own world, not to pre-conceived rules, and not necessarily to common sense (though ultimately we might want to explain common sense).
Personally, I'm currently wrestling with the Moria at marineford inconsistency - stealing shadows in broad daylight w/o the victims immediately disintegrating. I want to see if it was in fact "daylight" or was instead cloudy or something, but I suspect it was in fact daylight. I currently only have an unsatisfactory answer in regard to this one, which I am hesitant to even share - since his defeat by Luffy, he has learned new ways to utilize his powers, or is just utilizing them in a different way. This might be because, if the victim's body dies, the shadow dies with it; it would be very useful, if possible, to allow the victim to survive in order to maintain the power of their shadow. This is really unsatisfying because, while there may be some motivation, it is super vague. On the other hand, I am not yet convinced that something like that is straightforwardly impossible. I mention this example because I think this is precisely the goal - show that explaining this is impossible, or come up with some sort of plausible explanation. I also use this example to show that, despite the rigid concerns I've outlined above, it isn't entirely "all or nothing." While one person could legitimately believe something like "Moria is just using his powers differently than that other time, thus one piece physics makes sense," without a good explanation of exactly what that consists of another person might reasonably believe - though in no way have proven - that one piece physics really doesn't make sense. I can only add that similar debates also occur in real world physics and philosophy of physics and philosophy of science more generally.
I hope this makes sense and seems relevant. I spent almost an hour on my original post and I am super pissed I hit backspace outside of the textbox and deleted the whole thing -_-