This thesis investigates thc philosophical significance of linguistic meaning and rulcs. It questions thc assumption that rulcs of usage can function in substantial philosophical explanations of how meaning arises or of how communication is possible. Rather, such mlcs arc imponant bccausc thcy arc oftcn instrumental in thc treatment 0f conceptual confusions. Chapter 1 argues that mlcs of usage are philosophically significant not as prescriptive norms, but as descriptions of language usc. Thcy cannot dctcrminc thc meaning of words, nor draw thc linc bctwccn meaningful and nonsensical speech. Rather, they function as posterior registrations of cxprcsscd meanings. Illustrations arc given of how such mics can bc uscd t0 lay bare thc structure philosophical problems. Chapter 2 connects thc investigation to discussions of nonscnsicality in thc work of Cora Diamond, James Conant and Lars Hcrtzbcrg. The rolc of nonsense in philosophy is considcrcd, and thc character and philosophical significance of rulcs of usage arc cxplorcd in further detail. Chapter 3 deals with Saul Kripkc’s meaning-sceptical reading of Wittgenstein. The relation bctwccn rules and intentional phenomena such as wishes and expectations is investigated in detail, together with thc importance of practical agreement as a background to talk of meaning and mlcs. Chapter 4 discusses problems surrounding thc epistemology of understanding and communication. The exchange bctwccn John McDowell and Michael Dummctt on thcsc issues is considered in detail, and those aspects of McD0wcll’s position that axe congenial t0 what has been argued in previous chapters arc idcntiticd.