Sigmund Freud’s theory of life and death drives evolved throughout his life and career. Initially, he described a class of drives known as life instincts that he believed were responsible for much of our behavior.

Eventually, however, Freud came to believe that life instincts alone could not explain all human behavior. With the publication of his book "Beyond the Pleasure Principle" in 1920, Freud concluded that all instincts fall into one of two major classes: life drives and death drives—later dubbed Eros and Thanatos by other psychologists.

Eros was the god of love, fertility, and passion in ancient Greece. Thanatos was the human manifestation of death.

Verywell / JR Bee

Sometimes referred to as sexual instincts, the life drive deals with basic survival, pleasure, and reproduction. While we tend to think of life instincts in terms of sexual procreation, these drives also include instincts such as thirst, hunger, and pain avoidance. The energy created by the life drive is known as libido.

In early psychoanalytic theory, Freud proposed that the life drive was opposed by the forces of the ego, the organized, logic-driven part of a person's psyche that mediates desires. Later, he maintained that the life drive or Eros was opposed by a self-destructive death instinct, later known as Thanatos.

The life drive is focused on the preservation of life, both of the individual and of the species. This drive compels people to engage in actions that sustain their own lives, such as looking after their health and safety. It also exerts itself through sexual drives, motivating people to create and nurture new life. 

Behaviors commonly associated with life instincts include love, cooperation, and other ​prosocial actions.​ These behaviors support both individual well-being and the harmonious existence of a cooperative and healthy society.

Freud first introduced the concept of the death drive in his essay "Beyond the Pleasure Principle." He theorized that humans are driven toward death and destruction, famously declaring that "the aim of all life is death."

Freud believed that people typically channel this death drive outward, which manifests as aggression toward others. People also can direct this drive inward, however, which can result in self-harm or suicide.

Freud based this theory on clinical observations, noting that people who experience a traumatic event often recreate or revisit it. For example, he noted that soldiers returning from World War I tended to revisit their traumatic experiences in dreams that repeatedly took them back to combat.

From these observations, he concluded that people hold an unconscious desire to die but that life instincts largely temper this wish. In Freud's view, the compulsion to repeat was "something that would seem more primitive, more elementary, more instinctual than the pleasure principle which it overrides." Thus, Thanatos stands in stark contrast to the drive to survive, procreate, and satisfy desires.

As with much of Freud's work, controversy surrounds the concepts of life and death drives. One could argue that there are as many arguments for and against them as there are psychologists.

The death drive, in particular, is one of Freud's most disputed and complicated theories. Some see the death drive as incompatible with the sanctity of life and an explanation for (or even encouragement of) suicide. Some, like Todd Dufresne, professor of Philosophy at Lakehead University, even outright reject its existence. Psychoanalyst and psychotherapist Ben Kafka, associate professor at New York University, believes the concept to be flawed and not particularly relevant to contemporary life.

Likewise, the life drive is often oversimplified to mean libido, or the energy that drives sex and creativity.

Many in the field argue that Freud's thinking is a product of his times and doesn't make sense in the modern world. Most agree on one fact, however: "Drives" are abstract, and science can't verify or disprove their existence by any reliable, quantifiable measure.

Although Freud's theories are not as prominent as they once were, understanding your own self-preservation and self-destructive tendencies can be helpful for your well-being.

Life instincts might compel you to seek the healthy relationships and social support that are essential for emotional health. Destructive inclinations, on the other hand, might lead you to actions that are less healthy, such as aggressive or risky behavior.

Once you are able to recognize some of these tendencies, you might be better able to temper them and replace negative behaviors with more positive ones.

As in so many other areas, knowledge is power. Being aware can help people understand, minimize, and ultimately distance themselves from self-destructive thoughts and behaviors, freeing the mind for more positive ones.

The term "death drive" is used interchangeably with "death wish." In both cases, it refers to what psychologists call Thanatos: a subconscious desire to return to an inorganic state.

French psychoanalyst Jacques Lacan postulated that all other drives are "partial" to the death drive, which adherents called simply "the drive." He wrote that the drive pulls us back toward the time when we were one with our mothers, prior to birth and weaning.