Traditional skeptical arguments deny the possibility of knowledge on a priori grounds. However, most philosophers are not convinced by these arguments. A more recent empirical skeptical argument based on psychological results (put forward as part of the situationist challenge to virtue epistemology) is similarly unconvincing (to the extent that it is not taken to be, even by those who initially put it forward). The problem is that these arguments are better understood as a reductio for one of their premises than as a reason to adopt their conclusions.

However, this chapter argues that we can give an empirical argument based on other psychological data (in particular the phenomenon of implicit bias) that forms the basis of a genuine skeptical worry: it serves as evidence that we probably lack a lot of the knowledge that we normally take ourselves to have (and not merely as a reductio of one of its premises).