 Identifying the content of attitudes is a matter of identifying the objects of those attitudes, and, in the most basic cases, the objects of attitudes are identical with the causes of those same attitudes (as the cause of my belief that there is a bird outside my window is the bird outside my window). Identifying beliefs involves a process analogous to that of ‘triangulation’ (as employed in topographical surveying and in the fixing of location) whereby the position of an object (or some location or topographical feature) is determined by taking a line from each of two already known locations to the object in question – the intersection of the lines fixes the position of the object (this idea first appears in ‘Rational Animals [1982]). Similarly, the objects of propositional attitudes are fixed by looking to find objects that are the common causes, and so the common objects, of the attitudes of two or more speakers who are capable of observing and responding to one another’s behaviour. In ‘Three Varieties of Knowledge’, Davidson develops the idea of triangulation as a means to elaborate the three-way conceptual interdependence that he argues obtains between knowledge of oneself, knowledge of others and knowledge of the world. Just as knowledge of language cannot be separated from our more general knowledge of the world, so Davidson argues that knowledge of oneself, knowledge of other persons and knowledge of a common, ‘objective’ world form an interdependent set of concepts no one of which is possible in the absence of the others. 