The problem of ontology is inextricably linked with the problem of absoluteness-relativity of scientific knowledge. The article shows the erroneousness of the solution of these problems both in the classical rationalism of Descartes, Pascal, Bacon, Newton, which absolutized scientific knowledge, and in the post-positivism of Quine, Kuhn, Feyerabend, Popper, Lakatos that replaced it, which excessively relativized it. The article proposes a solution to these problems based on the unified method of substantiation of scientific theories developed by the author. When replacing one theory substantiated by a unified method of substantiation with another (Newton - Einstein), although contrary to classical rationalism, the definitions of concepts (that means ontology) and formulas change, but contrary to post-positivists, both theories guarantee the truth of their predictions with a given accuracy and probability in the area of action of each of these theories. Only these areas do not coincide. (The area of action of the theory of relativity is larger than the area of Newton's mechanics and includes it).
Alexander Voin (Mon,) studied this question.