Underlying orthodox evidence theory are a number of epistemological assumptions about the ability of reason to deliver true descriptions which accurately describe and correspond to the ‘real’ world. Drawing extensively on both traditional philosophical and contemporary, particularly postmodernist, scepticism this article provides a detailed critique of realist epistemological assumptions about reason, truth and knowledge. It argues that claims to reason, truth and knowledge can never escape the impact of individual perspective, community standards and power relations. At the same time, however, it rejects the realist assertion that subjectivism and relativism are oxymoronic or self-defeating positions. Instead, it is argued that epistemological scepticism is a healthy political position to adopt in that it guards against the complacent acceptance of seemingly authoritative assertions of reason, truth and knowledge.