The relationship between belief and knowledge is subtle. Believers in a claim typically say that they know that claim. For instance, those who believe that the Sun is a god will often report that they know that the Sun is a god. However, the terms belief and knowledge are used differently by philosophers. It is a telling point concerning the nature of belief that most people distinguish between what they know and what they believe, even though they consider both kinds of statements to be true.
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.
Beliefs are sometimes divided into core beliefs (those which you may be actively thinking about) and dispositional beliefs (those which you may ascribe to but have never previously thought about). 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 philosophers 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.
Beliefs form in a variety of ways. We tend to internalize the beliefs of the people around us. 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 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. 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.
The primary thrust of the advertising industry is that repetition forms beliefs, as do associations of beliefs with images of sex, love, and other strong positive emotions. Physical trauma, especially to the head, can also radically alter a person’s 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.