Hi Derek:

You wrote: "Can one "experience" anything without consciousness? Can one have a "representation" of anything without consciousness? The answers are not self-evidently yes. So one would be defining something in terms of ideas which already contain - or may very well contain - that something."

The answer to both of your questions is "yes". This answer will only be evident to someone who is acquainted with a competent theoretical model of the cognitive brain. As long as the terms "experience" and "representation" have no biophysical referents we remain stuck in a conceptual tar pit. Non-conscious experiences and representations actually constitute the major part of our cognitive activities (for a detailed explication of these neuronal processes, see The Cognitive Brain, MIT Press 1991).

What makes experiences or representations conscious? My claim is that they become conscious only when these preconscious brain events are projected into the 3D spatio-temporal manifold of the retinoid system, the brain's analog of egocentric space. This constitutes a phenomenal experience of something somewhere from a privileged egocentric perspective --  the hallmark of consciousness (see Space, self, and the theater of consciousness, Consciousness and Cognition, 2007).

AT