We extend an empirically grounded theory of the existence of quantum computer. The main question that we are considering is a question about the quantum computer’s possibility of existence and creation. As empirical evidence, we use logic, which we show in cognitive perspective. For a definition of the computer, we use a formal definition of Turing machine. By formulating many definitions abstractly and phenomenologically we go around the areas of quantum physics, quantum computing and other quantum-related fields of science which could give an unambiguous answer to our question about the essence of quantum computer and which is developed so they can’t. In many ways, it makes this theory about the existence of quantum computer universal for these areas, although less applied for them. We consider some corollary of the essences of quantum computer, including the possibility of quantum computer for the human. References to research of cognitive nature of logic suggest empirical basis which we follow in our theory.