Today's preoccupation with the problem of freedom via disorders, psychic traumas and hysterical symptoms in the subject, due to civilization based on the repression and renunciation of one's own nature, calls for a mutation based on the reading of Sigmund Freud. So, in order to remedy this crisis in modern society, which inevitably affects the individual's psychic personality given that it is a modern society based on ontological separation that makes the subject's nature ambiguous, we are invited, individually and collectively, to better discover Sigmund Freud's foundation of freedom. This rediscovery of man and the basis of his freedom in the light of psychoanalysis will help us to better appreciate modern currents of thought. For this reason, freedom in Sigmund Freud's psychoanalysis is a major issue. The thesis presents a rational methodology for the conception of freedom applied to Sigmund Freud's theory of psychoanalysis.