William James 
Pragmatism 

A profoundly influential figure in American psychology, William James (1842–1910) was also a philosopher of note, who used Charles S. Peirce’s theories of pragmatism as a basis for his own conception of that influential philosophy. For James, this meant an emphasis on ‘radical empiricism’ and the concept that the meaning of any idea — philosophical, political, social, or otherwise — has validity only in terms of its experiential and practical consequences.