In psychoanalysis, a self-preservation instinct that supplies energy to the ego in a defensive conflict, distinguished by Sigmund Freud (1856–1939) in his early (1910–15) classification from an object instinct, which is concerned with sexual or destructive relations to an external object. Freud introduced the concept in 1910 in an article on ‘The Psycho-Analytic View of Psychogenic Disturbance of Vision’ (Standard Edition, XI, pp. 211–18), the key passage being: ‘A quite specially important part is played by the undeniable opposition between the instincts which subserve sexuality, the attainment of sexual pleasure, and those other instincts which have as their aim the self-preservation of the individual—the ego-instincts’ (pp. 214–15). In his later classification from 1920 onwards, he recognized as ego instincts not merely sexual instincts subserved by Eros (the life instincts), but also destructive instincts subserved by Thanatos (the death instinct). See also ego interest.