Add to ORKGInfallibilism is the view that knowledge requires conclusive grounds. Despite its intuitive appeal, most contemporary epistemology rejects Infallibilism; however, there is a strong minority tradition that embraces it. Showing that Infallibilism is viable requires showing that it is compatible with the undeniable fact that we can go wrong in pursuit of perceptual knowledge. In other words, we need an account of fallibility for Infallibilists. By critically examining John McDowell’s recent attempt at such an account, this paper articulates a very important general lesson for Infallibilists. The paper concludes by briefly discussing two ways to do justice to this lesson: first, at the level of experience; and second, at the level of judgment