Many of Freud's concepts such as the Id and the Oedipus complex are said to occur at an unconscious level, making them difficult, if not impossible, to test. Furthermore, his ideas were based on the subjective case studies of individuals such as Little Hans. this makes it difficult to generalise and make universal claims about human behaviours. Therfore, this suaggest Freud's theory was pseudoscientific rather than established fact.