A social system consists in a plurality of individual actors interacting with each other in a situation which has at least a physical or environmenta… - Talcott Parsons

The structure of a theoretical system tells us what alternatives are open in the possible answers to a given question. If observed facts of undoubted accuracy will not fit any of the alternatives it leaves open, the system itself is in need of reconstruction.

Theory in the social sciences should have three major functions. First, it should aid in the codification of our existing concrete knowledge. It can do so by providing generalized hypotheses for the systematic reformulation of existing facts and insights, by extending the range of implication of particular hypotheses, and by unifying discrete observations under general concepts. Through codification, general theory in the social sciences will help to promote the process of cumulative growth of our knowledge. In making us more aware of the interconnections among items of existing knowledge which are now available in a scattered, fragmentary form, it will help us fix our attention on the points where further work must be done. Second, general theory in the social sciences should be a guide to research. By codification it enables us to locate and define more precisely the boundaries of our knowledge and of our ignorance. Codification facilitates the selection of problems, although it is not, of course, the only useful technique for the selection of problems for fruitful research. Further than this, general theory should provide hypotheses to be applied and tested by the investigation of these problems... Third, general theory as a point of departure for specialized work in the social sciences will facilitate the control of the biases of observation and interpretation which are at present fostered by the departmentalization of education and research in the social sciences.

Without deliberate planning on anyone's part, there have developed in our type of social system, and correspondingly in others, mechanisms which, within limits, are capable of forestalling and reversing the deep-lying tendencies for deviance to get into the vicious circle phase which puts it beyond the control of ordinary approval-disapproval and reward-punishment sanctions.