Hi I spent my last couple hours reading books and browsing this forum and web to get answer on my question, obviously in vain: I know that wave function for fermions should be antisymmetric, I know fermions spin should be half integer otherwise causality will broken (but I don't why yet), I know spinors can be represented by SU(2) and we can get from there the half integer and exclusion principle... But, as I understood from some books and ArXiv papers that basically, and despite the enormous implications of this principle starting from the "space occupied" by atoms to neutron stars formation, there is no clear intuitive explanation why two fermions with the same spin can't be at the same energetic level, and why there will be "repulsive" relations between them despite of that there is no actual "force" between them (contrary to what postulates some time in crystal studies), I agree that even so arguments such as particles has "consciousness" are interesting, they still meta-physical, why fermions are so different of Bosons? are there such a particles which with wave functions not symmetric nor antisymmetric? So is there any explanation in modern main-stream physics ? if not it will be really strange for me why such a very important principle didn't get enough attention? Thanks in advance.