Discusses a number of developments and consequences of my position. Firstly, there is the very important issue of the relation between the basic, essentially experiential, perceptual demonstrative contents that I have been considering up to this point, and the more detached, linguistically articulated and categorized judgements that a person more standardly makes on the basis of perception, and that constitute the normal expression of his perceptual knowledge about the world around him. Secondly, I argue that my account entails a version of Russell's Principle of Acquaintance (1917: 159), which I elucidate, on which singular reference is possible only to objects about which the subject is in a position to acquire, or to express, non-inferential knowledge Thirdly, I exploit this version of the Principle of Acquaintance to provide what seems to me to be a fully satisfying response to an important objection to the possibility of combining a so-called externalist theory of empirical content, of the kind that I myself favour and draw on in my account of perceptual knowledge, with a plausible account of a person's knowledge of the contents of his own beliefs.
Keywords: externalism, linguistic categorization, Principle of Acquaintance, Russell, self-knowledge