Eureka (word) "Eureka! Eureka!" after he had stepped into a bath and noticed that the water level rose, whereupon he suddenly understood that the volume of water displaced must be equal to the volume of the part of his body he had submerged. (This relation is "not" what is known as Archimedes' principle—that deals with the "upthrust" experienced by a body immersed in a fluid.) He then realized that the volume of irregular objects could be measured with precision, a previously intractable problem. He is said to have been so eager to share his discovery that he leapt out of his bathtub
The Discovery of the Unconscious nature", he concluded that it has "little critical value or real historical analysis." Frank Sulloway's "Freud, Biologist of the Mind" (1979) was partly inspired by "The Discovery of the Unconscious". The psychologist Hans Eysenck, writing in "Decline and Fall of the Freudian Empire" (1985), called "The Discovery of the Unconscious" a "classic" and an "excellent book which unveils many of the myths which have accumulated around Freud". The critic Frederick Crews considered "The Discovery of the Unconscious" part of a body of research demonstrating that Freud "was misled by his drive toward heroic fame." Crews wrote that the Ellenberger reveals