The unconscious mind is the aspect (or alleged aspect) of the mind of which we are not directly conscious or aware. The unconscious is also often referred to as the subconscious. The unconscious mind should not be confused with unconsciousness.
The idea originated in antiquity, and its more modern history is detailed in Henri F Ellenberger's Discovery of the Unconscious (Basic Books, 1970). The term was popularized by Sigmund Freud. He developed the idea that there were layers to human consciousness: the conscious, preconscious, and unconscious. He thought that certain psychic events take place "below the surface", or in the unconscious mind. A good example is dreams, which Freud called the "royal road to the unconscious".
In another of Freud's systematizations, the mind is divided into the Conscious mind or Ego and two parts of the Unconscious: the Id or instincts and the Superego. Freud used the idea of the unconscious in order to explain certain kinds of neurotic behavior. (See psychoanalysis.)
Many modern philosophers and social scientists either dispute the concept of an unconscious, or argue that it is not an entity that can be scientifically investigated or discussed rationally. In the social sciences, this view was first brought forward by John Watson, considered to be the first American behaviourist. Among philosophers, Karl Popper was one of Freud’s most notable contemporary opponents. Popper claimed that Freud’s theory of the unconscious was not falsifiable.
However, there is agreement among many, perhaps most, psychologists and cognitive scientists that much mental functioning takes place in a part of the mind inaccessible to consciousness.
Carl Jung developed the concept further. He divided the unconscious into two parts: the personal unconscious and the collective unconscious. The first of these corresponds to Freud's idea of the subconscious, though unlike his mentor, Jung believed that the personal unconscious contained a valuable counter-balance to the conscious mind, as well as childish urges. As for the collective unconscious, also called "the archetypes", this is the common store of mental building blocks that makes up the psyche of all humans. Evidence for its existence is the universality of certain symbols that appear in the mythologies of nearly all peoples.
There are other views. Jane Roberts (in the Seth books) presents a rich portrait of consciousness in which the unconscious mind is described as being clairvoyant and in communication with all other minds. The self that each of us experiences day-to-day is described as being but one facet of a richer and very complex multi-dimensional entity.
Somewhat related to the unconscious are nonconscious psychic events. The term nonconscious seems to be used in various ways – some appear to use the term to avoid the somewhat value-laden term “unconscious” or “subconscious” (but basically for the same purpose); some use it to refer to events that can only be observed indirectly (e.g. certain acts of short-term memory); some use it to point to events such as brain activity controlled mostly by the autonomic nervous system (e.g. emotional reactions to certain smells). Not surprisingly, there are no sharply delineated conventions for distinguishing exactly between the nonconscious and the unconscious – partly because they interact with each other, and partly because, as is so often the case, psychologists are unable to agree on the definitions.
A distinction needs to be made between The Unconscious (or the unconscious mind, or the subconscious), which are concepts in psychoanalysis and related fields, and unconscious or nonconscious events in the mind, which are of great interest in cognition and perception. There are connections and similarities between the two but it would be quite wrong to use these two concepts interchangeably.
(Note: The next section does confuse the two but has not been removed because of the interesting examples that it gives)
The unconscious is arguably not the most intuitive idea, so why bother with it? What's the evidence? What might the unconscious explain?
As some of the above examples indicate, material is constantly moving from the conscious mind to the unconscious and vice versa. The conscious mind only holds a small amount of information at any given time. In many cases information - especially easily accessible memories - can be called into awareness at will.
The Rediscovery of the Unconscious