Stream of consciousness is the idea that everyone has their own individual, stream of thought, that has no beginning or end. This stream is comprised of every experience that an individual has ever had and shapes his or her internal consciousness. This idea was written about by psychologist, William James. The basis of James' idea was that “Every new experience is inevitably molded and framed by all the old experiences that have gone before, and because this background constantly changes and enlarges, no two experiences can ever be precisely alike.” James also saw consciousness as being continuous, as well. Just like a stream doesn't have gaps in it's water source,the same is true to a stream of consciousness. These are things just on the level of consciousness, though. James believed that the human consciousness would remember what happened immediately before and immediately after an unconscious period, and merge the gaps into one fluid stream.
James in the 1890s
A Brief History of William James
William James was born in New York City, January 11th 1842.  His father, Henry James Sr., was determined to give his children the best education possible. As a result the family moved around the country to attend the best schools and institutions. As a result, the James children were very educated and knew many languages. Initially entering Harvard University as a chemistry student in 1861, he changed majors to physiology, and after graduating he attended Harvard Medical School.  While pursuing his M.D. he went on an expedition to the Amazon rainforest to explore the world of field biology.  While on the expedition he suffered from bouts of sicknesses, which gave him time to read books by Wilhelm Wundt and he became increasingly interested in the field of psychology. Soon after, James suffered from severe depression, where he even thought about suicide.  James eventually recovered from this depression and continued his studies of physiology. Soon after obtaining his M.D., James taught physiology at Harvard University. While at Harvard, James wrote about the popular idea of the stream of consciousness in his book Principles of Psychology. 
Long before William James' theories, the phrase stream of consciousness (Pali; viññāna-sota) occurs in early Buddhist scriptures.Hammalawa Saddhatissa Mahathera writes: "There is no 'self' that stands at the mentality to which characteristics and events accrue and from which they fall away, leaving it intact at death. The stream of consciousness, flowing through many lives, is as changing as a stream of water. This is the anatta doctrine of Buddhism as concerns the individual being." The Yogachara school of Mahayana Buddhism developed the idea into a thorough theory of mind. This theory of mind is known as mindstream, where the basic concept is an ongoing mind that can never be the same at one point of time to the next. It consists of the notion that everything that has ever happened to someone will change a person's mindstream into something that is unique at every point of time it existed. Another aspect is that a person has had a stream of mind since before he or she was born; there is not a definite beginning or an ending to the mind because it continues after death. . This theme that the mind acts apart from the body is very influential in Buddhist teachings. There is a definite separation from the brain and the mind, because the mind is something that cannot be controlled or tested. Every individual mind has unique aspects that cannot be determined by a physical entity, such as the brain. There is a question of how the mind, in this context, could have ever begun. Without previous experience of mind, the mind itself could not exist. 
James and Introspection
James was enormously skeptical about using introspection as a technique to understand human thoughts. He was adamant that using this method to dissect thoughts was futile: "Introspective analysis is in fact like seizing a spinning top to catch its motion, or trying to turn up the gas quickly enough to see how the darkness looks."James did not believe it was efficient to analyze thoughts by breaking them down. Instead of using introspection as a technique, he developed stream of consciousness as a way to harness the energy of human thought and to "meet and merge over the gap, much as the feelings of space of the opposite margins of the 'blind spot' meet and merge over that objective interruption to the sensitiveness of the eye. Such consciousness as this whatever it be for the on looking psychologist, is for itself unbroken. It feels unbroken." Stream of consciousness was James' counterargument to introspection; it was his solution to connect to the human mind while avoiding the traditional methods which, in his opinion, was hindering the process rather than helping it.
Stream of Consciousness
James defined four characteristics to thought, that give us a stream of consciousness. They are:
1.) "Every thought tends to be a part of a personal consciousness."
- Thought is completely unique to each individual and does not require secondary opinions or consciousness. Each person has his or her own personal stream that is made up of what he or she has seen and experienced. When an experience occurs, each and every person will create a recollection completely different, “so long as the existence of something” matches with a personal mind that can mold it into its own personal stream. 
2.) "Within each personal consciousness thought is always changing."
- When an individual has an experience, this changes his or her entire state of mind. If an individual takes in an experience one day at the same location, it will never be the same as the last. No state once gone can reoccur and be identical with what it was before. Take for example a person who wakes up every day and goes to a coffee shop. Each and every time he or she has that experience it changes the state of mind, which is ever changing and can never be revisited twice. 
3.) "Within each personal consciousness thought is sensibly continuous."
- When James defines continuity of a person's consciousness, he describes it as a river that has no breaks or separators of any kind. The only kind of delays a person would have with his or her consciousness would be time gaps between consciousness and unconsciousness, such as being asleep. James states that due to the effects of our consciousness being continuous, it means two fundamental things: that (a) "even with time gaps, as soon as the consciousness realizes that it was a part of a person’s experience, it registers it as a consciousness and molds it into itself,"  (b) "changes between consciousness type, such as awake and sleep, are never abrupt."
4.) "It is interested in some parts of these objects to the exclusion of others, and welcomes or rejects or chooses from."
- James boldly addresses the fact human, selective attention and deliberate will are examples of this phenomenon. Not many humans realize that this activity occurs very consistently on a daily basis, an example being the sound of a clock. The ticking sound is noticeable, but at times it is not. We can assume consciously that the clock is still going when we do not hear it it was only attention being directed away from it. We decide to ignore the stimulus because our consciousness chose where our attention is given based on interests.
Currently a view, like James', was proposed by Bernard Baars who developed Global Workspace Theory. Baars theory is built around the idea of a theater. In this metaphor, the stage is where the consciousness is the center of attention. The audience and back stage staff are the subconscious that are analyzing the situation, and changing the act as the show goes on. This is similar to James' work because the stream of consciousness is affected by every experience which reshapes the view of the consciousness. In Baars theory it is the audience and the backstage staff that change his or her consciousness. Susan Blackmore, one of James' critics, is a psychologist who challenges what James thought about how the human conscious processes life experiences. She suggests that the entire idea of a stream of consciousness is an illusion. Blackmore argues that people can't know for sure if they were conscious or not at a time that immediately passed when they questioned their own conscious against subconscious experiences.Cite error: A
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- William James Principles of Psychology (1890)
- William James Psychology: A Briefer Course; Stream of Consciousness (1892)
- James, W. (1890). The Principles of Psychology
- Fancher, R. E., & Rutherford, A. (2012). Pioneers of Psychology. New York: W. W Norton and Company, INC., p. 317
- Fancher, R. E., & Rutherford, A. (2012). Pioneers of Psychology. New York: W. W Norton and Company, INC.
- Baskerville, C. (1910). William James. American Association for the Advancement of Science.
- Specifically, in the Digha Nikaya. See Steven Collins, Selfless Persons; Imagery and Thought in Theravāda Buddhism.Cambridge University Press, 1982, page 257.
- Hammalawa Saddhatissa, Buddhist Ethics. Wisdom Publications, 1997, page 23.
- Dan Lusthaus, Buddhist Phenomenology: A Philosophical Investigation of Yogācāra Buddhism and the Ch'eng Wei-shih Lun.Routledge 2002, page 193.
- Chodron, T. (2012). Buddhism for Beginners: Shambhala Publications.
- James, W. (1890). The Principles of Psychology, p. 244
- James, W. (1890). The Principles of Psychology, p. 238
- James, W. (1892). Psychology, H. Holt and Company, p. 19
- James, W. (1890). The Principles of Psychology, p. 226
- James, W. (1890). The Principles of Psychology, p. 237
- . Baars, Bernard (1997), In the Theater of Consciousness New York: Oxford University Press