The implications of these considerations justify the statement that all empirically verifiable knowledge even the commonsense knowledge of everyday life – involves implicitly, if not explicitly, systematic theory in this sense. – Talcott Parsons

It is that of increasing knowledge of empirical fact, intimately combined with changing interpretations of this body of fact – hence changing general statements about it – and, not least, a changing a structure of the theoretical system. – Talcott Parsons

From all this it follows what the general character of the problem of the development of a body of scientific knowledge is, in so far as it depends on elements internal to science itself. – Talcott Parsons