How do we address philosophical arguments whose conclusions contradict our commonsense knowledge? For example: a logically impeccable argument that concludes that you cannot know that you are at this very moment reading a description of a book of philosophy. That is the problem of philosophical scepticism. Scepticism, Knowledge, and Forms of Reasoning is an attempt to resolve how best to respond to such vexing arguments, a matter on which there is no consensus among contemporary philosophers. Rather than denying the premises of such arguments or simply declaring them invalid, John Koethe delves into what such arguments reveal about the nature of reasoning itself. He suggests that there is nothing straightforwardly wrong with sceptical arguments, and that in recognizing this while at the same time honoring our commonsense convictions about knowledge, we confront profound questions about the very nature of reasoning.