A weaker epiphenomenalism

A prominent objection to epiphenomenalist theories of qualia, on which qualia have no causal efficacy, is that then we have no way of knowing that we had a quale of red. For a redness-zombie, who has no quale of red, would have the very same “I am having a quale of red” thought as me, since my “I am having a quale of red” thought is not caused by the quale of red.

There is a slight tweak to epiphenomanalism that escapes this objection, and the tweaked theory seems worth some consideration. Instead of saying that qualia have no causal efficacy, on our weaker epiphenomenalism we say that qualia have no physical effects. We can then say that my “I am having a quale of red” thought is composed of two components: one of these components is a physical state ϕ₂ and the other is a quale q₂ constituting the subjective feeling of thinking that I am having a quale of red. After all, conscious thoughts plainly have qualia, just as perceptions do, if there are qualia at all. We can now say that the physical state ϕ₂ is caused by the physical correlate ϕ₁ of the quale of red, while the quale q₂ is wholly or partly caused by the quale q₁ of red.

As a result, my conscious thought “I am having a quale of red” would not have occurred if I lacked the quale of red. All that would have occurred would be the physical part of the conscious thought, ϕ₂, which physical part is what is responsible for further physical effects (such as my saying that I am having a quale of red).

If this is right, then the induced skepticism about qualia will be limited to skepticism with respect to unconscious thoughts about qualia. And that’s not much of a skepticism!