2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/94145It is shown that propositional calculuses of both quantum and classical logics are non-categorical. We find that quantum logic is in addition to an orthomodular lattice also modeled by a weakly orthomodular lattice and that classical logic is in addition to a Boolean algebra also modeled by a weakly distributive lattice. Both new models turn out to be non-orthomodular. We prove the soundness and completeness of the calculuses for the models. We also prove that all the operations in an orthomodular lattice are five-fold defined. In the end we discuss possible repercussions of our results to quantum computations and quantum computers.21 pages, AMSLaTeX, to be published in Helvetica Physica Acta, a few typos corrected, Author's URL http://m3k.grad.hr/pavicicQuantum PhysicsLogicQuantum Algebratext