If Mary already knew all physical facts and still learns something new, the new knowledge cannot be of a physical fact.

McGrew is not alone in holding that experiential or phenomenal features can, by virtue of our direct awareness of them, constitute the content of a special class of concepts. Gertler (2001, 2011, 2012), Chalmers (2003, 2010), and Nida-Rümelin (2004) defend views very much in the same spirit. Gertler (2001) distinguishes between ordinary demonstratives, which typically involve an intention to pick out an entity that satisfies some description, and a pure demonstrative, which picks out its referen