First lines of the Introduction (as abstract not provided): In The Many Faces of Realism, Hilary Putnam suggests that although the phenomenon of conceptual relativity has become pervasive in contemporary scientific practice, “contemporary logicians and meaning theorists generally philosophize as if it did not exist.”2 Putnam suggests that since the end of the nineteenth century, modern scientists have begun to take note of a variety of ‘non-classical’ phenomena, in particular the idea that “there are ways of describing what are (in some way) the ‘same facts’ which are (in some way) ‘equivalent’ but also (in some way) ‘incompatible’.”3 Rather than concluding that we are presented in such situations with a factual contradiction between two competing descriptions that must be decided one way or the other, Putnam urges us instead to recognise the way in which the employment of different concepts at a fundamental level can generate incompatible descriptions of the same phenomena that are, in some sense, equivalent.