A prevalent 19th-century belief was the notion of “psychic energy” (also known as “subliminal self”), which lay behind our motivation to behave a certain way. Freud believed not only in the existence of this psychic power but also that it continued to exert a strong influence on our conscious thoughts, especially those relating to sex. He believed that it continued to exert an influence on us even when we were unaware of it.
The fundamental energy comes from our lust for life, which manifests itself in instincts for food and drink, sex, and intimacy. As it is connected to the pleasure principle, it drives the id, the single entirely unconscious component of the psyche (the only one without opposites). Hedonistic impulses prompted by this psychical energy may clash with the moderating influence exerted by the ego and superegos. Freud later identified an opposite form of psychical energy, what he called death drives – impulses toward self-destruction and a desire to return to an inorganic state.