The paper gives an analysis of the theoretical-methodological principles of the philosophy of J. Patočka not only as a historian of philosophy, but also as a historian of science, especially of its revolutionary periods. The aim of the paper is to show that following the general context of his works here also Patočka consistently deals with the central issue of his philosophy, namely the life-world (the original Husserlian concept of Lebenswelt). In Patočkaś view it was already the rise of ancient philosophy, and especially of the mathematical natural science that destroyed the original uniform picture of the universe, splitting manś world into the natural world on one hand and the world construed by the mathematical natural science on the other hand. Further, the paper shows Patočkaś view of phenomenology, which he has seen as a means, with the help of which this dichotomy could be resolved, as well as Patočkaś criticism of the original Husserlian concept of phenomenology, which failed to avoid its subjectivist and solipsist tendencies. The problem of lifeworld led Patočka not only to the principles of non-subjective phenomenolog, but it also became the basis of his philosophy of the history of philosophy.