Qualia

The terms ‘quale’ and ‘qualia’ (plural) are most commonly understood to mean the qualitative, phenomenal or ‘felt’ properties of our mental states, such as the throbbing pain of my current headache, or the peculiar blue of the afterimage I am experiencing now. Though it seems undeniable that at least some of our mental states have qualia, their existence raises a number of philosophical problems.

The first problem regards their nature or constitution. Many theorists have noted great differences between our intuitive conceptions of qualia and those of typical physical properties such as mass or length, and have asked whether qualia could nonetheless be identical with physical properties. Another problem regards our knowledge of qualia, in particular, whether our beliefs about them can be taken to be infallible, or at least to have some kind of special authority.