Well, he wasn't a relativist. There's a long and complicated story of the rise of a desire for scientific relativism. Part of it may well be simply s… - Ian Hacking

Opinion is the companion of probability within the medieval epistemology.

From any vocabulary of ideas we can build other ideas by formal combinations of signs. But not any set of ideas will be instructive. One must have the right ideas.

Notice that there is no sociology in the book. Scientific communities and their practices are, however, at its core, entering with paradigms, as we saw, at page 10 and continuing to the final page of the book. There had been sociology of scientific knowledge before Kuhn, but after Structure it burgeoned, leading to what is now called science studies. This is a self-generating field (with, of course, its own journals and societies) that includes some work in the history and the philosophy of sciences and technology, but whose emphasis is on sociological approaches of various kinds, some observational, some theoretical. Much, and perhaps most, of the really original thinking about the sciences after Kuhn has had a sociological bent.
Kuhn was hostile to these developments. In the opinion of many younger workers, that is regrettable. Let us put it down to dissatisfaction with growing pains of the field, rather than venturing into tedious metaphors about fathers and sons. One of Kuhn’s marvelous legacies is science studies as we know it today.