Qualia; The Hard problem of consciousness

Philosophers often use the term ‘qualia’ to refer to the introspectively accessible, phenomenal aspects of our mental lives. In this broad sense of the term, it is difficult to deny that there are qualia. Disagreement typically centers on which mental states have qualia, whether qualia are intrinsic qualities of their bearers, and how qualia relate to the physical world both inside and outside the head. The status of qualia is hotly debated in philosophy largely because it is central to a proper understanding of the nature of consciousness. Qualia are at the very heart of the mind-body problem. In the past, philosophers have often appealed directly to introspection on behalf of the view that qualia are intrinsic, non-intentional features of experiences.

Do frogs have qualia? Or fish? What about honey bees? Somewhere down the phylogenetic scale phenomenal consciousness ceases. But where? It is sometimes supposed that once we begin to reflect upon much simpler beings than ourselves — snails, for example — we are left with nothing physical or structural that we could plausibly take to help us determine whether they are phenomenally conscious

Which Mental States Possess Qualia?

(1) Perceptual experiences (2) Bodily sensations (3) Felt reactions (4) Felt moods

Functionalism is the view that individual qualia have functional natures, that the phenomenal character of, e.g., pain is one and the same as the property of playing such-and-such a causal or teleofunctional role in mediating between physical inputs (e.g., body damage) and physical outputs (e.g., withdrawal behavior). On this view (Lycan 1987), qualia are multiply physically realizable. Inner states that are physically very different may nonetheless feel the same. What is crucial to what it is like is functional role, not underlying hardware.


Some say that the explanatory gap is unbridgeable and that the proper conclusion to draw from it is that there is a corresponding gap in the world. Experiences and feelings have irreducibly subjective, non-physical qualities (Jackson 1993; Chalmers 1996, 2005). Others take essentially the same position on the gap while insisting that this does not detract from a purely physicalist view of experiences and feelings. What it shows rather is that some physical qualities or states are irreducibly subjective entities (Searle 1992). Others hold that the explanatory gap may one day be bridged but we currently lack the concepts to bring the subjective and objective perspectives together. On this view, it may turn out that qualia are physical, but we currently have no clear conception as to how they could be (Nagel 1974). Still others adamantly insist that the explanatory gap is, in principle, bridgeable but not by us or by any creatures like us. Experiences and feelings are as much a part of the physical, natural world as life, digestion, DNA, or lightning. It is just that with the concepts we have and the concepts we are capable of forming, we are cognitively closed to a full, bridging explanation by the very structure of our minds (McGinn 1991).


Clarifying qualia evidently goes hand in hand with motivating and clarifying the distinction between properties of ordinary physical objects and properties of experiences.

Reflection on the way we have introduced qualia will make it clear that the arguments for them can function also as arguments for dualism, that is, as arguments for the view that there is something in the world besides our bodies, the parts of our bodies, and the ordinary physical objects that lie outside us. For this reason, acceptance of qualia has often been seen as an intolerable offense to the dominant late-twentieth century ideology of materialism. Thus, an enormous literature exists, the point of which is to explain away the threat that qualia present to materialism. A lesser, but growing body of literature has arisen in which qualia are defended against these attacks.

Since other articles in this Field Guide address various materialist arguments against qualia realism, the focus in the present article is upon positive arguments for qualia. There is, however, one piece of dialectic that may be usefully identified here. Some materialists take comfort in the view that qualia realists (sometimes known as "qualophiles") cannot prove that dualism is true. The argument for this denial, however, sometimes boils down to the claim that qualia realists cannot prove that materialism is false. It is evident that materialism is most secure against attack by qualia realists when the content of "materialism" is very small. We thus find some materialists whose firm attachment to materialism is proportional to the emptiness of the materialism they assert. Experience, they hold, is certainly material; but as to how that could be true, or how we might find out whether it is true, or even what in the future will be held to be essential for a thing to be "material", are matters on which we are now ignorant. It has ev