 A feature of both the triangulation argument, and the Davidsonian account of radical interpretation, is that the attribution of attitudes must always proceed in tandem with the interpretation of utterances – identifying content, whether of utterances or of attitudes, is indeed a single project. An inability to interpret utterances (that is, an inability to assign meanings to instances of putative linguistic behaviour) will thereby imply an inability to attribute attitudes (and vice versa). A creature that we cannot interpret as capable of meaningful speech will thus also be a creature that we cannot interpret as capable of possessing contentful attitudes. Such considerations lead Davidson to deny that non-linguistic animals are capable of thought – where thought involves the possession of propositional attitudes such as beliefs or desires (see especially ‘Thought and Talk’). This does not mean that such animals have no mental life at all, nor does it mean that we cannot usefully use mental concepts in explaining and predicting the behaviour of such creatures. What it does mean, however, is that the extent to which we can think of such creatures as having attitudes and a mental life like our own is measured by the extent to which we can assign determinate propositional content to the attitudes we would ascribe to those creatures. A further consequence of this view is that the idea of an untranslatable language – an idea often found in association with the thesis of conceptual relativism – cannot be given any coherent formulation. Inability to translate counts as evidence, not of the existence of an untranslatable language, but of the absence of a language of any sort (see ‘On the Very Idea of a Conceptual Scheme’ [1974])