Doxa

Doxa (; from verb ) is a common belief or popular opinion. In classical rhetoric, "doxa" is contrasted with "episteme" ('knowledge').
Etymology.
The term "doxa" is an ancient Greek term () that comes from the verb "dokein" (), meaning 'to appear, to seem, to think, to accept'.
Between the 3rd and 1st centuries BCE, the term picked up an additional meaning when the Biblical Hebrew word for 'glory' () was translated by the Septuagint as "doxa". This translation of the Hebrew scriptures was used by the early Church, causing the term to be frequently used in the New Testament. The term is also used in the worship services of the Greek Orthodox Church, where the glorification of God in true worship is also seen as true belief. In that context, "doxa" reflects behavior or practice in worship, and the belief of the whole church rather than personal opinion. It is the unification of these multiple meanings of "doxa" that is reflected in the modern terms "orthodoxy" and "heterodoxy". This semantic merging in the word "doxa" is also seen in Russian word "slava" (слава), which means 'glory', but is used with the meaning of "praise" or "worship" in words like "pravoslavie" (православие), meaning 'orthodoxy' (or, literally, 'true belief', 'true way of worship') deriving more from the verb 'славить' - "to praise".
In philosophy.
Plato.
In his dialogue "Gorgias," Plato presents the sophists as wordsmiths who ensnared and used the malleable doxa of the multitude to their advantage without shame. In this and other writings, Plato relegated "doxa" as being a belief, unrelated to reason, that resided in the unreasoning, lower-parts of the soul. 
This viewpoint extended into the concept of "doxasta" in Plato's "theory of forms", which states that physical objects are manifestations of doxa and are thus not in their true form. Plato's framing of "doxa" as the opponent of knowledge led to the classical opposition of error to truth, which has since become a major concern in Western philosophy. (However, in the "Theaetetus" and in the "Meno", Plato has Socrates suggest that knowledge is "orthos doxa" for which one can provide a "logos", thus initiating the traditional definition of knowledge as "justified true belief.") Thus, error is considered in as pure negative, which can take various forms, among them the form of illusion.
Aristotle.
Aristotle, Plato's student, objected to Plato's theory of doxa. Aristotle perceived that doxa's value was in practicality and common usage, in contrast with Plato's philosophical purity relegating doxa to deception. Further, Aristotle held doxa as the first step in finding knowledge ("episteme"), as doxa had found applications in the physical world, whereby those who held it had a great number of tests done to prove it and thus reason to believe it. Aristotle clarifies this by categorizing the accepted truths of the physical world that are passed down from generation to generation as "endoxa". Endoxa is a more stable belief than "doxa", because it has been "tested" in argumentative struggles in the "Polis" by prior interlocutors. The term "endoxa" is used in Aristotle's "Organon", "Topics" and "Rhetoric".
Pyrrho.
In Pyrrhonism, "doxa" and "dogma" that pertain to non-evident matters form the target of Pyrrhonist practice. In regard to such matters, practitioners 'suspend judgment' ("epoché") to induce 'unperturbed-ness' ("ataraxia").
In sociology and anthropology (Bourdieu).
Pierre Bourdieu, in his "Outline of a Theory of Practice" (1972), used the term "doxa" to denote a society's taken-for-granted, unquestioned truths. In comparison, "opinion" is the sphere of that which may be openly contested and discussed. The "doxa", in Bourdieu's view, is the experience by which "the natural and social world appears as self-evident." It encompasses what falls within the limits of the thinkable and the sayable ("the universe of possible discourse"); that which "goes without saying because it comes without saying."
Bourdieu's "Distinction" (1979) provides the humanist instances of his application of the term, where "doxa" sets out limits on social mobility within the social space that are on the characteristic consumption of each social individual: certain cultural artifacts are recognized by "doxa" as being inappropriate to actual social position; hence, "doxa" helps to petrify social limits—the "sense of one's place"—and one's sense of belonging, which is closely connected with the idea that "this is not for us" ("ce n'est pas pour nous"). Accordingly, individuals become voluntary subjects of those incorporated mental structures that deprive them of more deliberate consumption.
Bourdieu also explains the term "doxa" in his interview with theorist Terry Eagleton, where he uses an example about common beliefs in school. He asked students what qualifies as achievement in school. In response, the students on the lower end of the academic spectrum viewed themselves as being inferior or not as smart as the students who excelled. Doxa is evident in this response, because this was the common belief and attitude that the students had based on what society pushed them to believe.
Bourdieu believes that doxa derives from socialization, as socialization also deals with beliefs that derive from society; as we grow up in the environment, we tend to believe what society tells us is correct. Adding on to his previous example, Bourdieu contends that it is a socially-accepted misconception that if you do not score as high as someone else, then you are obviously not as smart as they are. Scores do not prove that one is smarter, because there are many different factors that play into what you score on a test. People may excel within a certain topic and fail at another. However, even though it is a misconception, people tend to partake in common practices to make themselves feel better. In the case of common beliefs in school, the students who feel inferior due to popular belief that they are not as smart as the students who score higher than they, may experiment with drugs to ease the insecurities they face. Bourdieu believes that doxa is more than common belief: it also has the potential to give rise to common action.
In political theory.
While doxa is used as a tool for the formation of arguments, it is also formed "by" argument. The former can be understood as told by James A. Herrick in "The History and Theory of Rhetoric: An Introduction":The Sophists in Gorgias hold that rhetoric creates truth that is useful for the moment out of doxa, or the opinions of the people, through the process of argument and counterargument. Socrates will have no part of this sort of 'truth' which, nevertheless, is essential to a democracy. Importantly noted, democracy, which by definition is the manifestation of public opinion, is dependent upon (and therefore also constrained by) the same limits imposed upon the individuals responsible for its establishment. Due to compromised opinions within a society, as well as opinions not counted for due to inaccessibility and apathy, doxa is not homogeneous, nor is it created agreeably. Rather, it is pliable and imperfect—the outcome of an ongoing power struggle between clashing "truths."
To expand upon his argument in "Outline of a Theory of Practice", Pierre Bourdieu writes: "When there is a quasi-perfect correspondence between the objective order and the subjective principles of organization (as in ancient societies) the natural and social world appears as self-evident. This experience we shall call doxa." Adam T. Smith of the University of Chicago observes: "Bourdieu consigns the practices of the denizens of ancient societies to the realm of doxa, their lives cast as routines predicated upon the mis-recognition of social orders as natural ways of life, rather than political products." This calls to attention that the notion of social order as naturally occurring is misperceived, disregarding its creation by political argumentation. "Doxa", then, can be understood as created by argument as well as used in the formation of argument, essential for the establishment of democratic policies.