Many years ago we often witnessed a testy insistence, on the part of some purist, that some very familiar philosophical ‘ism’ be defined before being discussed; when most people either thought that had been done already or were happy to wait for the discussion itself to identify the ‘ism’. The old new style, that featured those unexpected demands for definition, ended by trying people's patience in its turn. Today there is a widespread assumption that we know, well enough, what is meant in philosophy by Scepticism. Perhaps the majority view is something like this:

The philosophical term Scepticism admittedly covers a number of different stances. The one that a given philosopher wants to discuss may or may not be the most like that of the original ancient Skeptics. Still the context normally makes it clear enough what is meant, and there is more point in discussing whatever thing is meant than in quarrelling about the name. As for the way, or ways, in which the word scepticism with a small s is used when people are not referring to any traditional philosophical position—we can safely disregard colloquial usage in this context. As a rule the main point is to see how, if at all, the Scepticism in question is best combated or refuted.