The paper aims at outlining of two different streams of the evolutionary theory of knowledge. The latter results from the interdisciplinary approach to the evolution of knowledge. Within it two main streams crystalized scientific and philosophical ones. The former (which also has its own philosophical „superestructure“, deriving from scientific research achievements) is seen by its representatives as the only evolutionary theory of knowledge in the full sense of the word. The two streams differ in their approaches to the evolution of knowledge due to their origin, their research methods and first of all to their substantially different concept of knowledge. The author is concerned to show the prospects and the limits of both of them as well.