Why is it that the difference, in particular that between logical and phenomenal possibility, is of philosophical relevance? First, it is interesting to note how it is precisely those states of affairs and worlds just characterized as phenomenally possible which appear as intuitively plausible to us: We can define intuitive plausibility as a property of every thought or idea which we can successfully transform into the content of a coherent phenomenal simulation. In doing so, the internal coherence of a conscious simulation may vary greatly. The result of a certain thought experiment, say, of Swampman traveling to Inverted Earth (Tye 1998) may intuitively appear as plausible to us, whereas a dream, in retrospect, may look bizarre. Of course, the reverse is possible as well. Again, it is true that phenomenal possibility is always relative to a certain class of concrete representational systems and that the mechanisms of generating and evaluating coherence employed by those systems may have been optimized toward functional adequacy and not subject to any criteria of epistemic justification in the classic epistemological sense of the word.31 In passing, let me briefly point to a second, more general issue, which has generated considerable confusion in many current debates in philosophy of mind. Of course, from phenomenal possibility (or necessity), neither nomological nor logical possibility (or necessity) will follow. The statement that all of us are purportedly able to coherently conceive of or imagine a certain situation—for instance, an imitation man (K. K. Campbell 1971, p. 120) or a zombie (see Chalmers 1996, p. 94ff.)—is rather trivial from a philosophical point of view because ultimately it is just an empirical claim about the history of the human brain and its functional architecture. It is a statement about a world that is a phenomenally possible world for human beings. It is not a statement about the modal strength of the relationship between physical and phenomenal properties; logical possibility (or necessity) is not implied by phenomenal possibility (or necessity). From the simple fact that beings like ourselves are able to phenomenally simulate a certain apparently possible world, it does not follow that a consistent or even only an empirically plausible description of this world exists. On the contrary, the fact that such descriptions can be generated today shows how devoid of empirical content our current concept of consciousness still is (P. M. Churchland 1996).