Freud's theories profoundly impacted psychology, psychiatry, literature, and philosophy, but were controversial and criticized for a lack of empirical evidence. A few theories have been debunked ...

He was having, he wrote, "grave doubts" about his theory, leaving him in a state of what he described as "fathomless, and bottomless laziness, intellectual stagnation", Freud confessed.

And this is something that Freud thought Breuer had failed to see. "The plunging into sexuality in theory and practice," Breuer wrote, "is not to my taste." Breuer objected that Freud had ...