William James is one of the most prominent philosophers of America of 19-20th cc. He made a great contribution into the development of a philosophical thought of his time. He also widely uses his experience of psychologist in his works on philosophy. In his works he mainly speaks about thinking and knowledge which he treats as instruments in the struggle to live that may be the result of his psychological practice. Also one of the most important themes of his works is pragmatism. He generalized the pragmatism of Charles Sanders Peirce by asserting that the meaning of any idea must be analyzed in terms of the succession of experiential consequences it leads to the idea that truth and error depend solely on these consequences. He applied pragmatism to the analysis of change and chance, freedom, variety, pluralism, and novelty. Pragmatism was also the basis for his polemic against monism, the