The book presents results from research conducted by Zygmunt Zawirski on the theory of knowledge, quantum mechanics, logic, ontology and metaphysics. The works undertaken in the field of logic, methodology and philosophy of science, and in particular the philosophy of nature and natural science testify to a solid preparation for the fundamental task of developing contemporary scientific philosophy. The emerging mathematical natural science did not have those possibilities which emerged in the 20th Century and which Zygmunt Zawirski (1882-1948) used. In the development of scientific metaphysics, he took into account both the achievements of modern logic, mathematics and physics. Zawirski builds scientific metaphysics by referring to