Belief is the psychological state in which an individual holds a proposition or premise to be true. Dispositional and occurrent belief concerns the contextual activation of the belief into thoughts (reactive of propositions) or ideas (based on the belief's premise).
Belief, knowledge and epistemology 
The terms belief and knowledge are used differently in philosophy.
Epistemology is the philosophical study of knowledge and belief. The primary problem in epistemology is to understand exactly what is needed in order for us to have true knowledge. In a notion derived from Plato's dialogue Theaetetus, philosophy has traditionally defined knowledge as "justified true belief". The relationship between belief and knowledge is that a belief is knowledge if the belief is true, and if the believer has a justification (reasonable and necessarily plausible assertions/evidence/guidance) for believing it is true.
A false belief is not considered to be knowledge, even if it is sincere. A sincere believer in the flat earth theory does not know that the Earth is flat. Later epistemologists, for instance Gettier (1963) and Goldman (1967), have questioned the "justified true belief" definition.
Belief as a psychological theory 
Mainstream psychology and related disciplines have traditionally treated belief as if it were the simplest form of mental representation and therefore one of the building blocks of conscious thought. Philosophers have tended to be more abstract in their analysis, and much of the work examining the viability of the belief concept stems from philosophical analysis.
The concept of belief presumes a subject (the believer) and an object of belief (the proposition). So, like other propositional attitudes, belief implies the existence of mental states and intentionality, both of which are hotly debated topics in the philosophy of mind, whose foundations and relation to brain states are still controversial.
Beliefs are sometimes divided into core beliefs (that are actively thought about) and dispositional beliefs (that may be ascribed to someone who has not thought about the issue). For example, if asked "do you believe tigers wear pink pajamas?" a person might answer that they do not, despite the fact they may never have thought about this situation before.
That a belief is a mental state has been seen by some as contentious. While some have argued that beliefs are represented in the mind as sentence-like constructs, others have gone as far as arguing that there is no consistent or coherent mental representation that underlies our common use of the belief concept and that it is therefore obsolete and should be rejected.
This has important implications for understanding the neuropsychology and neuroscience of belief. If the concept of belief is incoherent, then any attempt to find the underlying neural processes that support it will fail.
- Our common-sense understanding of belief is correct - Sometimes called the "mental sentence theory," in this conception, beliefs exist as coherent entities, and the way we talk about them in everyday life is a valid basis for scientific endeavour. Jerry Fodor is one of the principal defenders of this point of view.
- Our common-sense understanding of belief may not be entirely correct, but it is close enough to make some useful predictions - This view argues that we will eventually reject the idea of belief as we use it now, but that there may be a correlation between what we take to be a belief when someone says "I believe that snow is white" and how a future theory of psychology will explain this behaviour. Most notably, philosopher Stephen Stich has argued for this particular understanding of belief.
- Our common-sense understanding of belief is entirely wrong and will be completely superseded by a radically different theory that will have no use for the concept of belief as we know it - Known as eliminativism, this view, (most notably proposed by Paul and Patricia Churchland), argues that the concept of belief is like obsolete theories of times past such as the four humours theory of medicine, or the phlogiston theory of combustion. In these cases science hasn't provided us with a more detailed account of these theories, but completely rejected them as valid scientific concepts to be replaced by entirely different accounts. The Churchlands argue that our common-sense concept of belief is similar in that as we discover more about neuroscience and the brain, the inevitable conclusion will be to reject the belief hypothesis in its entirety.
- Our common-sense understanding of belief is entirely wrong; however, treating people, animals, and even computers as if they had beliefs is often a successful strategy - The major proponents of this view, Daniel Dennett and Lynne Rudder Baker, are both eliminativists in that they hold that beliefs are not a scientifically valid concept, but they don't go as far as rejecting the concept of belief as a predictive device. Dennett gives the example of playing a computer at chess. While few people would agree that the computer held beliefs, treating the computer as if it did (e.g. that the computer believes that taking the opposition's queen will give it a considerable advantage) is likely to be a successful and predictive strategy. In this understanding of belief, named by Dennett the intentional stance, belief-based explanations of mind and behaviour are at a different level of explanation and are not reducible to those based on fundamental neuroscience, although both may be explanatory at their own level.
How beliefs are formed 
Psychologists study belief formation and the relationship between beliefs and actions. Beliefs form in a variety of ways:
- We tend to internalise the beliefs of the people around us during childhood. Albert Einstein is often quoted as having said that "Common sense is the collection of prejudices acquired by age eighteen." Political beliefs depend most strongly on the political beliefs most common in the community where we live. Most individuals believe the religion they were taught in childhood.
- People may adopt the beliefs of a charismatic leader, even if those beliefs fly in the face of all previous beliefs, and produce actions that are clearly not in their own self-interest. Is belief voluntary? Rational individuals need to reconcile their direct reality with any said belief; therefore, if belief is not present or possible, it reflects the fact that contradictions were necessarily overcome using cognitive dissonance.
- Advertising can form or change beliefs through repetition, shock, and association with images of sex, love, beauty, and other strong positive emotions.
- Physical trauma, especially to the head, can radically alter a person's beliefs.
However, even educated people, well aware of the process by which beliefs form, still strongly cling to their beliefs, and act on those beliefs even against their own self-interest. In Anna Rowley's Leadership Theory, she states "You want your beliefs to change. It's proof that you are keeping your eyes open, living fully, and welcoming everything that the world and people around you can teach you." This means that peoples' beliefs should evolve as they gain new experiences.
To "believe in" someone or something is a distinct concept from "believe-that." There are two types of belief-in:
- Commendatory - an expression of confidence in a person or entity, as in, "I believe in his ability to do the job."
- Existential claim - to claim belief in the existence of an entity or phenomenon with the implied need to justify its claim to existence. It is often used when the entity is not real, or its existence is in doubt. "He believes in witches and ghosts" or "many children believe in Santa Claus" are typical examples.
Delusional beliefs 
Delusions are defined as beliefs in psychiatric diagnostic criteria (for example in the Diagnostic and Statistical Manual of Mental Disorders). Psychiatrist and historian G.E. Berrios has challenged the view that delusions are genuine beliefs and instead labels them as "empty speech acts," where affected persons are motivated to express false or bizarre belief statements due to an underlying psychological disturbance. However, the majority of mental health professionals and researchers treat delusions as if they were genuine beliefs.
In Lewis Carroll's Through the Looking-Glass the White Queen says, "Why, sometimes I've believed as many as six impossible things before breakfast." This is often quoted in mockery of the common ability of people to entertain beliefs contrary to fact.
See also 
- Cognitive dissonance
- Collective belief
- Culture-specific syndrome
- Doxastic logic
- Evil eye
- Expectation (epistemic)
- Folk psychology
- Gettier problem
- Life stance
- Moore's paradox
- Observer-expectancy effect
- Propositional attitude
- Propositional knowledge
- Psychosomatic illness
- Spell (paranormal)
- Subject-expectancy effect
- Subjective validation
- Sugar pill
- superficial charm
- Thomas theorem
- Ultimate importance
- Unintended consequence
- Value (personal and cultural)
- Schwitzgebel, Eric (2006), "Belief", in Zalta, Edward, The Stanford Encyclopedia of Philosophy, Stanford, CA: The Metaphysics Research Lab, retrieved 2008-09-19
- Gettier, E. L. (1963). "Is justified true belief knowledge?". Analysis 23 (6): 121–123. JSTOR 3326922.
- Goldman, A. I. (1967). "A causal theory of knowing". The Journal of Philosophy 64 (12): 357–372. JSTOR 2024268.
- Bell, V.; Halligan, P. W.; Ellis, H. D. (2006). "A Cognitive Neuroscience of Belief". In Halligan, Peter W.; Aylward, Mansel. The Power of Belief: Psychological Influence on Illness, Disability, and Medicine. Oxford: Oxford University Press. ISBN 0-19-853010-2.
- Baker, Lynne Rudder (1989). Saving Belief: A Critique of Physicalism. Princeton University Press. ISBN 0-691-07320-1.
- Gelman, Andrew; Park, David; Shor, Boris; Bafumi, Joseph; Cortina, Jeronimo (2008). Red State, Blue State, Rich State, Poor State: Why Americans Vote the Way They Do. Princeton University Press. ISBN 978-0-691-13927-2.
- Argyle, Michael (1997). The Psychology of Religious Behaviour, Belief and Experience. London: Routledge. p. 25. ISBN 0-415-12330-5. "Religion, in most cultures, is ascribed, not chosen."
- Hoffer, Eric (2002). The True Believer. New York: Harper Perennial Modern Classics. ISBN 0-06-050591-5.
- Kilbourne, Jane; Pipher, Mary (2000). Can't Buy My Love: How Advertising Changes the Way We Think and Feel. Free Press. ISBN 0-684-86600-5.
- Rothschild, Babette (2000). The Body Remembers: The Psychophysiology of Trauma and Trauma Treatment. New York: W. W. Norton & Company. ISBN 0-393-70327-4.
- Rowley, Anna (2007). Leadership Therapy: Inside the Mind of Microsoft. Basingstoke: Palgrave Macmillan. p. 69. ISBN 1-4039-8403-4.
- MacIntosh, J. J. (1994). "Belief-in Revisited: A Reply to Williams". Religious Studies 30 (4): 487–503. doi:10.1017/S0034412500023131.
- Macintosh, Jack. "Belief-in". The Oxford Companion to Philosophy. p. 86. ISBN 978-0-19-926479-7.
|Look up belief in Wiktionary, the free dictionary.|
- Belief entry by Eric Schwitzgebel in the Stanford Encyclopedia of Philosophy
- How Belief Works Article from Derrick Farnell on the formation of beliefs.
- William Kingdon Clifford. Ethics of Belief Classic essay arguing that beliefs (and the processes that form them) have ethical implications, with counterpoint essay from William James entitled "The Will to Believe".