The dissertation critically examines Husserl's transcendental idealism as a response to epistemological skepticism. Contrary to prevailing interpretations, I argue that Husserl intended to formulate a non-reductive, idealist justification of empirical knowledge. I take the standard phenomenalistic interpretation of Husserl's idealism to be right in discerning his basic concern with the refutation of skepticism, but wrong in construing the transcendental reduction as an ontological reduction of the natural world to "ideal" sets of transcendental experiences. On the other hand, recent "neutrality views" (...) which hold that phenomenological epoche requires the permanent suspension of ontological commitments seem to confuse Husserl's quasi-verificationist critique of traditional metaphysics with the positivistic critique of all metaphysics. I suggest instead that Husserl's epistemological program be understood as an attempt to ground transcendentally, i.e. on the basis of apodictic and presuppositionless evidences, our ordinary beliefs about the world. In this light, Husserl's Weltvernichtung argument for the presuppositionlessness of consciousness can be seen as a necessary precondition of the transcendental justification of empirical knowledge. ;To clarify Husserl's genetic phenomenology, I adopt Dagfinn Follesdal's interpretation of the noema as a Fregean Sinn. I distinguish two levels of 'constitution' to show how Husserl traces back the sense and being of the objective world to the synthetic activity of the transcendental subject. The resolution of transcendental analogues of skeptical doubts by means of Husserl's analysis of 'retroactive cancellation' completes, in general outline, the grounding of the "verificationism" of the natural attitude. However, I argue that the anti-skeptical force of 'retroactive cancellation' depends on conceiving the relationship between the conscious subject and the world in a way that renders Weltvernichtung unintelligible. Husserl's transcendental idealist response to the skeptic accordingly leads to a dilemma: either one maintains the presuppositionlessness of consciousness but abandons the critique of skepticism for a descriptive study of the transcendental structures of experience; or one attempts to reformulate Husserl's phenomenological verificationism while abandoning the goal of absolute grounding. (shrink)