Socrates is not generally associated with constructivist philosophy. Nonetheless, this anecdote highlights the fact that discussions which link epistemology and learning have been taking place for thousands of years. From the perspective of psychology, epistemology considers the genesis and the nature of knowledge and includes learning. Knowledge, its nature and how we come to know, are essential considerations for constructivists. Von Glasersfeld describes constructivism as a "theory of knowledge with roots in philosophy, psychology and cybernetics". In the constructivist perspective, knowledge is constructed by the individual through his interactions with his environment.