Abstract Relativism about knowledge attributions is the view that a single occurrence of ‘S knows [does not know] that p’ may be true as assessed in one context and false as assessed in another context. It has been argued that relativism is equipped to accommodate all the data from speakers’ use of ‘know’ without recourse to an error theory. This is supposed to be relativism’s main advantage over contextualist and invariantist views. This paper argues that relativism does require the attribution (...) of semantic blindness to speakers, viz. to account for sceptical paradoxes and epistemic closure puzzles. To that end, the notion of semantic blindness is clarified by distinguishing between content-blindness and index-blindness, and it is argued that the attribution of index-blindness required by the relativist account is implausible. Along the way, it is shown that error-theoretic objections from speakers’ inter-contextual judgments fail against relativism. Content Type Journal Article Pages 1-19 DOI 10.1007/s11098-011-9783-5 Authors Dirk Kindermann, Arché, University of St Andrews, 17–19 College Street, St Andrews, KY16 9AL UK Journal Philosophical Studies Online ISSN 1573-0883 Print ISSN 0031-8116. (shrink)