This study examines the relationship between thought and language by considering the views of Kant and the later Wittgenstein alongside many strands of contemporary debate in the area of mental content. Building on an analysis of the nature of concepts and conceptions of objects, Dr Gillett develops an account of psychological explanation and the subject of experience. He offers a novel perspective on mental representation and linguistic meaning which accommodates the vexed topics of cognitive roles and singular thought. He concludes by outlining certain considerations relevant to sceptical arguments and the nature of perception. Gillett's analysis produces interesting correlations with current work in cognitive and developmental psychology, and is directly relevant to continuing work in epistemology, philosophy of mind, and philosophical psychology.