The sceptic stalks prominently through recent philosophical literature. Indeed some philosophers have managed to suggest that scepticism is the central issue in philosophy, although others have regarded such issues as futile or empty. Sceptical arguments certainly take many different forms, but it is helpful at least to begin by presenting what may be called a standard scepticism, so that variations in the sceptic’s position can be measured against this standard. Just as the sceptic’s positions offer a complex variety of view, so it is to be expected that attempts at a refutation of the sceptic will be equally complex. In a similar way it might be thought that a distinction could be drawn in SCL between its strictly linguistic and its theoretical principles. Nevertheless, as in the earlier cases, the sceptic’s argument points usefully to certain features of such languages and their institution.