If you disagree with your instructor's explanations...you should be able to back up physically your opinion. It means you simply counter his/her technique.If your counter works - you are right and if you can counter all his techniques, well, you become instructor and he must learn from you
However, if he is able to do his technique successfully anyway, well, bow deeply, shut up and train harder.
As you see, it is so easy to solve your problem. Hope it helps.
Hi Szczepan, don't know how serious you are about this, but this is not going to work. The instructor might be doing something wrong while I don't have the skill back up my opinion physically. Should I then do my best to learn the teacher's decent way or should I try to improve my own good way?
And I have often seen teachers use this type of argument against students: "what you are doing is wrong because I can counter it like this". Well, if someone with more aikido experience than me, who already knows what I will be doing and who can adjust his attack to facilitate his counter to my technique, is not able to consistently counter my technique, I'd run out of their dojo screaming.
So while taking the discussion to a physical level may determine who is the better fighter, it will not determine whose ideas about aikido are the best.