Dugald Stewart was an influential teacher and philosopher during the final years of the Scottish Enlightenment. Until recently he has been seen as merely a significant expositor of Thomas Reid's common sense philosophy. This thesis does not attempt to assess the novelty of Stewart's writings in relation to his Scottish predecessors such as Reid: rather, it offers a detailed historical study of aspects of his work, placing them in the political and cultural context of the period following the French Revolution. Two questions stimulated this thesis. First, what prompted Stewart, a moral philosopher who was not an experimental philosopher, to write a major work on methodology? Second, why was there a gap of twenty-two years between the first volume of his Elements of the Philosophy of the Human Mind (1792) and the second (1814), which contained his methodological treatise? I aim to answer these questions by offering a contextual intellectual history of some important aspects of Stewart's work. The thesis argues that Stewart faced a new problem: he had to deal with attacks on moral philosophy - the core subject of the Edinburgh University curriculum - some of which were produced by institutional and political factors affecting the Scottish universities, others by the rising authority of the experimental physical sciences. I consider a selection of Stewart's writings in the light of this problem. In 1804 Stewart's own student, Francis Jeffrey, gave public voice to the charge that the science of mind (which constituted the central part of Scottish common sense philosophy) was outdated, unscientific and useless. Thereafter, Stewart was engaged in what he saw as an urgent task - the defence of the very status of philosophy and the role of the philosopher. The thesis considers some of his major works (and other writings) from this perspective: Philosophical Essays (1810) contained his first direct retort to Jeffrey; Stewart's treatment of methodology in Elements of the Philosophy of the Human Mind, Volume 2 (1814) and his section on intellectual character in Volume 3 (1827) are viewed as two significant components of his attempt to reassert the primacy of moral philosophy and the role of the moral philosopher.