Abstract

The principal claim of this work is that humans have no perceptual knowledge of the external world. My defense of this claim differs from traditional skeptical arguments by not imposing excessive conditions on knowledge. I avoid premises asserting that knowledge requires things like knowing that one knows, ruling out all logically possible alternatives, the impossibility of mistake, or some form of certainty. To help insure that no such condition is imposed, I proceed from within various theories of knowledge developed since Gettier. Further support for this approach comes from recent attempts to evaluate skeptical arguments while being neutral about what the correct theory of knowledge is. I contend that such attempts have failed. I propose that we abandon such neutrality and in stead take an explicitly theory-dependent stance toward evaluating skeptical arguments. Chapters 1 and 2 argue for these methodological points. ;Chapters 3 through 7 evaluate some skeptical arguments from the perspective of numerous and diverse theories of knowledge. Each of these skeptical arguments employs an epistemic principle regarding underdetermination or an epistemic principle regarding the preservation of knowledge under known entailment. In each case, I articulate the needed principles to suit the theory at hand; then I go on to determine how the theory assesses the resulting skeptical argument. I investigate how skeptical arguments interact with the contextualism of Keith DeRose, the process reliabilism of Alvin Goldman, the internalist foundationalisms of John Pollock and Paul Moser, and the internalist coherentism of Keith Lehrer. In each case, I articulate one skeptical argument that the theory does not convincingly dismiss. The series of investigations constitutes a novel and updated inductive argument for skepticism about the external world