The routine knowledge people have of their everyday world and activities. Different sociological approaches adopt different attitudes to commonsense knowledge. The concept is central to Alfred Schutz's phenomenological sociology, where it refers to organized and ‘typified’ stocks of taken-for-granted knowledge upon which activities are based and which, in the ‘natural attitude’, is not questioned. This idea forms the basis of Peter Berger and Thomas Luckmann's theory (The Social Construction of Reality, 1967). For ethnomethodologists, commonsense (or, as it is frequently termed, ‘tacit’) knowledge is a constant achievement, in which people draw on implicit rules of ‘how to carry on’, which produce a sense of organization and coherence. Anthony Giddens builds this idea into his theory of structuration (The Constitution of Society, 1984). For symbolic interactionists and other interpretive sociologists, there is a less rigorous analysis of commonsense knowledge, but the central aim of sociology is seen as explicating and elaborating on people's conceptions of the social world, and sociological analysis must always be rooted in these conceptions.
However, some sociologists see commonsense knowledge as different from, if not opposed to, sociological understanding. For Émile Durkheim, sociology must break free of commonsense perceptions (prejudices), before we can produce scientific knowledge of the social world. For Marxists, much commonsense knowledge is ideological, or at least very limited in its understanding of the world. These approaches tend to emphasize the scientific nature of sociology and, in the case of Marxists, the importance of the revolutionary party to organize and guide the working class.