This paper sets out to draw together a number of themes shared by four papers, three of which appear in this publication [Kopnina and Cherniak; Pashby and Andreotti (see EJ1108094); Sund (see EJ1108100) ; and Van Poeck, Goeminne and Vandenabeele (see EJ1108089)]. The frame of reference employed as a means of relating the papers is Rorty's (1979/2009) concept of "abnormal discourse". For Rorty, the maintenance of challenge to established artefacts of thought that most people consider to be certain, self-evident and beyond question (i.e. challenge to "normal discourse": the terminology is, of course, borrowed from Thomas Kuhn) is crucial, whatever those artefacts of thought happen to be at any particular time and place.