In a VeryWell article, it states: "His work supported the belief that not all mental illnesses have physiological causes" (Cherry 1). It also demonstrated psychological and behavioral changes based on cultural differences. Through his research we can understand human development, personality and clinical psychology. Sigmund Freud's research is important to more fundamental understandings of psychology such as counseling and psychotherapy. The clinical practices and psychiatry he discovered are used today in many psychiatric practices and other clinical practices. It has also changed the way we look at the conscious and unconscious mind. Freud created the three levels of the mind, the first of which is the preconscious. This contains everything that could be in the conscious mind. The next level is the conscious mind which contains all thoughts and feelings at any given moment. In addition to this level it also includes our memory. The last level represented is the unconscious mind. It contains what may be our thoughts and feelings, but it influences our behaviors. This allows us to know which feelings, thoughts, memories and impulses are associated with consciousness and unconsciousness. One of his greatest achievements was the creation of the term psychoanalysis. It is a set of psychological theories and therapeutic techniques created by Freud's work. The world of psychology would not be the same without Sigmund's work and theories