Customs, common interpretations, institutions, shared routines, habitualizations, the who-is-who and who-does-what in social processes and the division of labor, constitute a much larger part of knowledge in society.

Language links up commonsense knowledge with finite provinces of meaning, thus enabling people, for example, to interpret dreams through understandings relevant in the daytime.

It can refer to experiences pertaining to finite provinces of meaning, it can span discrete spheres of reality...Language soars into regions that are not only de facto but also a priori unavailable to everyday experience."p. 40.

Regarding the function of language and signs, Berger and Luckmann are indebted to George Herbert Mead and other figures in the field known as symbolic interactionism, as acknowledged in their Introduction, especially regarding the possibility of constructing objectivity.

This reduces uncertainty and danger and allows our limited attention span to focus on more things at the same time, while institutionalized routines can be expected to continue “as previously agreed”: “Habitualization carries with it the important psychological gain that choices are narrowed… the background of habitualized activity opens up a foreground for deliberation and innovation [which demand a higher level of attention]… The most important gain is that each [member of society] will be able to predict the other's actions.

Symbolic universes are a set of beliefs “everybody knows” that aim at making the institutionalized structure plausible and acceptable for the individual—who might otherwise not understand or agree with the underlying logic of the institution.

Proverbs, moral maxims, wise sayings, mythology, religions and other theological thought, metaphysical traditions and other value systems are part of the symbolic universe.

“The function of legitimation is to make objectively available and subjectively plausible the ‘first-order’ objectivations that have been institutionalized… Proverbs, moral maxims and wise sayings are common on this level… [as well as] explicit theories… symbolic processes… a general theory of the cosmos and a general theory of man… The symbolic universe also orders history.

It locates all collective events in a cohesive unity that includes past, present and future.” (p. 110-120) Universe-maintenance refers to specific procedures undertaken, often by an elite group, when the symbolic universe does not fulfill its purpose anymore, which is to legitimize the institutional structure in place.

An intrinsic problem presents itself with the process of transmission of the symbolic universe from one generation to another… [additionally] two societies confronting each other with conflicting universes will both develop conceptual machinery designed to maintain their respective universes… mythology represents the most archaic form of universe-maintenance… theological thought may be distinguished from its mythological predecessor simply in terms of its greater degree of theoretical systematization… Modern science is an extreme step in this development.

E.g. shame for nudity comes from primary socialization, adequate dress code depends on secondary: A relatively minor shift in the subjective definition of reality would suffice for an individual to take for granted that one may go to the office without a tie.

What seems to be a useless and unnecessary communication of redundant banalities is actually a constant mutual reconfirmation of each other's internal thoughts, in that it maintains subjective reality.

Our final social location in the institutional structure of society will ultimately also influence our body and organism.

While both sexuality and nutrition are grounded in biological drives… biological constitution does not tell him where he should seek sexual release and what he should eat.” (p. 163-183) In 1998 the International Sociological Association listed it as the fifth-most important sociological book of the 20th century, behind Max Weber's The Protestant Ethic and the Spirit of Capitalism (1905) but ahead of Pierre Bourdieu's Distinction (1979).