“Religious doctrines … are all illusions, they do not admit of proof, and no one can be compelled to consider them as true or to believe in them.”

Austrian physician and psychoanalyst of the late 19th and early 20th centuries, Freud is best known for founding psychoanalysis and exploring the unconscious mind through techniques like free association. His theories on the structure of personality—id, ego, and superego—and the role of early childhood experiences in shaping behavior remain foundational in psychology.