Consensus reality (rarely or mistakenly called "consensual reality") is an approach to answering the question "What is real?", a profound philosophical question, with answers dating back to prehistory; it is almost invariably used to refer to human consensus reality, though there have been mentions of feline and canine consensus reality. It gives a practical answer - reality is either what exists, or what we can agree by consensus seems to exist; the process has been (perhaps loosely and a bit imprecisely) characterised as "when enough people think something is true, it... takes on a life of its own." The term is usually used disparagingly as by implication it may mean little more than "what a group or culture chooses to believe," and may bear little or no relationship to any "true reality", and, indeed, challenges the notion of "true reality". For example, Steven Yates has characterised the idea that the United States Federal Reserve Notes (not "backed" by anything) are "really worth a dollar" as "part of what we might call our consensus-reality... not... real reality."

The difficulty with the question stems from the concern that human beings do not in fact fully understand or agree upon the nature of knowledge or knowing, and therefore (it is often argued) it is not possible to be certain beyond doubt what is real.Accordingly, this line of logic concludes, we cannot in fact be sure beyond doubt about the nature of reality. We can, however, seek to obtain some form of consensus, with others, of what is real. We can use this to practically guide us, either on the assumption it seems to approximate some kind of valid reality, or simply because it is more "practical" than perceived alternatives. Consensus reality therefore refers to the agreed-upon concepts of reality which people in the world, or a culture or group, believe are real (or treat as real), usually based upon their common experiences as they believe them to be; anyone who does not agree with these is sometimes stated to be "in effect... living in a different world."

Throughout history this has also raised a social question: What shall we make of those who do not agree with consensus realities of others, or of the society they live in? Children have sometimes been described or viewed as "inexperienced with consensus reality" , although with the expectation that they will come into line with it as they mature. However, the answer is more problematic as regards such people as have been characterised as eccentrics, mentally ill, divinely inspired or enlightened, or evil or demonic in nature. Alternatively, differing viewpoints may simply be put to some kind of "objective" (though the nature of "objectivity" goes to the heart of the relevant questions) test. Reality enforcement is a term used[citation needed] for the coercive enforcement of the culturally accepted reality, upon non-conforming individuals. It has varied from indifference, to incarceration, to death.

Source : www.wikipedia.org