This Element is about Wittgenstein's engagement with skepticism. Two forms of skepticism will be at the center of this Element: skepticism concerning our knowledge of the 'external world,' and skepticism concerning our knowledge of 'other minds.' It will be shown that Wittgenstein is neither a skeptic nor an anti-skeptic. Rather, Wittgenstein thinks of the skeptic's doubt as a form of denial: a denial of knowledge that one cannot but have. The aim of this Element is to bring out what it means to