The aim of the project is to investigate three modern ways of answering the sceptical challenge within epistemology. These three strategies are externalism, contextualism and transcendental arguments, all of which have aroused a great deal of interest within analytic philosophy. The first two strategies reject two different assumptions of traditional epistemology, while the third turns the sceptical challenge against itself. Externalism rejects the assumption that an epistemological subject must be able to give reasons for its knowledge-claims in order to qualify as knowing it. Contextualism denies that knowledge is a context- independent entity. The aim of transcendental arguments is to show that the sceptic assumes something he or she purports to doubt. The project intends to answer the question whether these three strategies succeed. In order to do so an adequate analysis of the structure of sceptical arguments is needed. On the basis of such an analysis and an investigation of these three strategies, the project will also investigate the role of aprioristic knowledge claims in arguments against scepticism (that is, knowledge claims not based on experience). Sceptical arguments are highly relevant for philosophy. Even if sceptical conclusions are not drawn, many philosophical positions employ sceptical arguments in their criticism of traditional views of knowledge. Relativism is an example. It is thus of general interest to investigate sceptical arguments and the three strategies which philosophers have tied their hopes to.