Sigmund Freud (May 6 1856 - September 23 1939) was an Austrian neurologist, who was interested in hypnotism and how it could be used to help the mentally ill. Freud soon realized that hypnotism could not directly help people overcome their fears and concerns as well as simply talking about them. From this he soon invented "the talking cure" which we now speak of as psychoanalysis. Though his radical work inspired generations of scientists in all fields, Freud's theories are hotly debated by academics to this day, and some consider his theories to be pseudoscience.
Freud believed that humans were driven by two instinctive drives, libidinal energy/eros and the death instinct/thanatos. Freud's description of Eros/Libido included all creative, life-producing instincts. The Death Instinct represented an instinctive drive to return to a state of calm, or non-existence and was based on his studies of protozoa. (See: Beyond the Pleasure Principle).
Freud dealt mankind the most severe narcissistic injury of all -- that we are not entirely aware of what we even think! The concept of the unconscious was groundbreaking in that he proposed that awareness existed in layers and there were thoughts occurring "below the surface." Dreams, called the "royal road to the unconscious" provided the best examples of our unconscious life. The Preconscious was described as a layer between conscious and unconscious thought -- that which we could access with a little effort. The term "subconscious" while popularly used, is not actually part of psychoanalytical terminology.
Freud also pioneered the concepts of Id, Ego and Superego. The Id (Latin, = "it" = "es" in the original german) represented primary process thinking -- our most primitive need gratification type thoughts. The Superego represented our conscience and counteracted the Id with moral and ethical thoughts. The Ego -- stands in between both to balance our primitive needs and our moral/ethical beliefs. A healthy ego provides the ability to adapt to reality and interact with the outside world in a way that accommodates both Id and Superego.
Freud was interested in tribal cultures and studied rituals and belief systems such as the incest taboo. Freud used the Greek tragedy by Sophocles Oedipus Rex to point out how strongly we are against incest -- in all cultures. The Oedipus conflict was described as a state of psychosexual development and awareness. Alongside this Freud described many stages of psychosexual growth: Oral, Anal, Phallic, Latency, Genital. Each stage is a progression into adult sexual maturity and the ability to delay need gratification.
Today Freudian theory has been modified by countless empirical findings and theoretical debates. Freuds primary contribution was to introduce new ways of thought that those following him would elaborate upon. Freud's work is the foundation for modern psychology and most psychotherapy, and he remains known as the Father of Psychoanalysis. -- Perry Staltaro, PsyD