In this paper, death and immortality ideas of Russian cosmists are in syncretic way put together with key ideas in postmodern philosophy. The problem considered in world philosophy on creating co-evolutionary conditions for the emergence of «immortal» man is illustrated by a wide variety of ideas and concepts. This paper contains innovative ideas of the Russian cosmists as the starting point of the research. Special attention is paid to the extraordinary teachings of N. F. Fedorov, who is the founder of (...) Russian Cosmic philosophy. Using the system-diachronic method and technologies of ascending from the abstract to the concrete, the author compares the ideas of Russian cosmism with manifest concepts of modern philosophy (synergetics, phenomenology, transhumanism). The author also gives the most striking facts of discoveries of modern natural science and draws conclusions about ideas of Russian cosmists that have been put forward ahead of their time and retained their relevance and ontological potential until now. The paper presents the prospects for further studying the heritage of Russian cosmism to search for philosophical tools that could, without going beyond the limits of ethical universals, successfully combine the controversial theoretical directions of modern philosophy for the future positive practical development of society. (shrink)