Short answers, pulled from the story.
Belief is a subjective attitude that something is true or that a state of affairs is the case. In epistemology, philosophers use the term to refer to attitudes about the world that can be either true or false. To believe something is to take it to be true, such as accepting the proposition that snow is white.
An occurrent belief is one a person is actively entertaining, such as actively thinking that the Grand Canyon is in Arizona. A dispositional belief is inactive and becomes occurrent only when needed or relevant, then falls back into its dormant state. The great majority of beliefs are dispositional most of the time.
Full beliefs are all-or-nothing attitudes, meaning either one holds a belief in a proposition or one does not. Partial beliefs, called credences, come in degrees formalized by numbers between 0 and 1, where 1 is absolute certainty and 0 is absolute disbelief. In the Bayesian approach these degrees are interpreted as subjective probabilities.
Justified true belief is a definition of knowledge stating that to know a proposition is true, one must believe the true proposition and also have justification for that belief. It gained approval during the Enlightenment, with "justified" set in contrast to "revealed." The theory suffered a setback with the popularisation of Gettier problems.
De dicto and de re beliefs differ in how singular terms like names contribute to the meaning of a belief or its ascription. A belief is de dicto when substituting co-referring terms does not preserve truth-value, and de re when it does. Lois Lane believes Superman is strong but not that Clark Kent is strong, despite both names referring to the same person.
Eliminativism holds that strictly speaking there are no beliefs, arguing that nothing in the natural world corresponds to our common-sense concept of belief. Paul and Patricia Churchland are its most notable proponents, comparing belief to discarded ideas like the four humours theory of medicine or the phlogiston theory of combustion. They expect neuroscience to reject the belief hypothesis entirely.
Belief revision refers to the modification of beliefs, often modeled by Bayesian updating for its mathematical basis and conceptual simplicity. Influences on belief formation include childhood internalization, charismatic leaders, advertising through repetition, and physical trauma to the head. Whether a belief changes depends not only on evidence but on factors like the message source's credibility, social pressures, and anticipated consequences.