[3] Epicurus in the ancient world, and later Jeremy Bentham, laid stress upon the role of pleasure in directing human life, the latter stating: "Nature has placed mankind under the governance of two sovereign masters, pain and pleasure".
[5] Freud used the idea that the mind seeks pleasure and avoids pain in his Project for a Scientific Psychology of 1895,[6] as well as in the theoretical portion of The Interpretation of Dreams of 1900, where he termed it the 'unpleasure principle'.
[11] Freud contrasted the pleasure principle with the counterpart concept of the reality principle, which describes the capacity to defer gratification of a desire when circumstantial reality disallows its immediate gratification.
In infant and early childhood, the id rules behavior by obeying only the pleasure principle.
[13] By examining the role of repetition compulsion in potentially over-riding the pleasure principle,[14] Freud ultimately developed his opposition between Libido, the life instinct, and the death drive.