Although its originators looked for certainties to replace preestablished dogmas, modernity effectively involves the institutionalisation of doubt. All knowledge claims, in conditions of modernity, are inherently circular, although "circularity" has a different connotation in the natural as compared to the social sciences. In the former, it concerns the fact that science is pure method, such that all substantive forms of "accepted knowledge" are in principle open to being discarded. The social sciences presume a circularity in a twofold sense, which is constitutively fundamental to modern institutions. The knowledge claims they produce are all in principle revisable, but also become "revised" in a practical sense as they circulate in and out of the environment they describe.

Anthony Giddens, The Consequences of Moderni…, loc. 408