Anti-Realism and Skepticism about external world

Philosophical skepticism about the external world is an epistemological view that denies the possibility of grasping knowledge about the external world. One category of this kind of skepticism uses a skeptical hypothesis to prove that we can’t know anything about the external world. This hypothesis is a hypothetical description of the world that is different from the way we normally consider it to be. By using the fact that we don’t know, for example, that we are not brains in a vat, the skeptic argues that we know nothing about the external world. But it seems that this kind of skepticism can be threatening just to those philosophers who have accepted a kind of metaphysical realism about the external world. On the contrary, in this paper, it is argued that philosophical skepticism can be threatening to both anti-realism and realism about external world; Accepting anti-realism does not block skepticism about the external world.