 Recall the key epistemological challenge described in the introduction: how can we learn about the real world through merely thinking about imagined scenarios? This challenge sits at the center of the discussion even though we must note that not all of the work discussed below focuses on it directly. Still, this section describes six views that can be seen as responding in some way to this challenge: The Skeptical Objection, The Intuition-Based Account, The Argument View, Conceptual Constructivism, Experimentalism, and The Mental-Model Account.