The idea that the rational function in humans exists alongside the motor and emotional functions has been a neglected part of Western knowledge for at least two thousand years. It was stated by Aristotle, who was heavily influenced by the Gnostics, and the idea has been further developed since then by the Sufis. The rational does not supersede the other parts but is there in addition to the functions that came from the line of species humans evolved from. Each of these functions is physiologically and psychologically independent and equally important for a person to be able to realise their full human potential. The Gurdjieff system contains a comprehensive psychological system based on this idea of man being a three force being who has a definite place in the order of life on the earth and in the solar system. The purpose of the psychology of the Gurdjieff system is to teach people to develop in a balanced way psychologically and show the way to spiritual growth and understanding.