We have a recurring disconnect here. The question is ways of knowledge -- and the topic of knowledge being discussed is whether "aiki is a clash of forces" -- That problem begs physical descriptions to discuss meaningfully -- It certainly may admit methodological descriptions as well.
But appeals to authority are not a basis for rational discussion -- they are appeals to trust, maybe decent rhetorical devices -- but not rational arguments. Reason does not depend on trust. That is one reason why reason is particularly useful. A certificate or degree does not prove or disprove anything. Just because I have a law degree does not mean a layman is wrong on the law when he disagrees with me -- the law is a VERY BIG THING. The physical world is even bigger.
Is it true that there is only one way of knowing something? -- Only one way of describing something? Only one useful way?
Not in physics. Not in engineering. Many different conventions exist for different purposes and each is judged on their usefulness of description or application. Methodological approaches ARE more useful for some purposes -- but so what? A magnetic field has two mutually irreconcilable conceptual conventions for its physical description -- and yet both are indispensably useful and one cannot
be substituted for the other for certain purposes. Only one of them is for complex currents where there are objects in the field (and, FWIW the concept of torque
is useful there too in relating things involving complex magnetic field currents).
Anyone is free to reserve their own judgment on the purpose of the knowledge and its utility -- but objective description is objective description. Unless a concept that fits the facts better is available, you work with and test the best concepts you can find with the facts that you observe. I work from my personal observations and experience to found my concepts. I presume everyone else does also.
This is an observation of the human body -- I have one -- and others at my disposal...