I will discuss the links between functionalism and qualia by examining the views of Shoemaker and raising some questions.
What Is Functionalism?
Functionalism claims that mental states are individuated by what they do. That means they are not differentiated by how they are instantiated, or what their “substrate” is.
What Are Qualia?
Qualia are “subjective feels.” Here that means what it is like to be in a particular mental state.
What Is The Qualia-Based Objection To Functionalism?
Shoemaker responds to an objection from Block and Fodor. They object that functionalism cannot accommodate qualia.
There are links here to Chalmers’ “hard question.” That is to say, why is it like that, or indeed, why is it like anything at all to be in a particular mental state? The motivation for the objection is that some mental states are individuated by what it is like to be in them.
The objection proceeds by considering the possibilities of inverted qualia and absent qualia. The first means that it may be different for me when I am in the same mental state as you. The second means that it may be different for me to be in that same mental state. There is nothing it is like for me to in the same mental state as you perhaps. That could be true even though that state does indeed have some phenomenological character for you.
What Is The Problem For Functionalism?
Both possibilities would be fatal for functionalism. Finer grained distinctions between my mental state and yours would exist. Moreover, phenomenological characteristics differentiate them and not functional ones.
Similarly, Shoemaker asks whether it is plausible to suggest that the phenomenological character of mental states could be unrelated to their functional role. The question concerns the inputs, outputs and connections to other mental states.
Presumably a mental state with the phenomenological character of “intense pain” always results in a strong desire to exit that mental state. We want to move into a mental state without that phenomenological character.
If “intense pain” state had no phenomenological character, that would reduce desire to exit the mental state. If what I feel as pain is what you feel as pleasure, you would not wish to exit at all. This seems to comport poorly with the idea that we are in the same mental state at all. The lack of fit results from deciding the question on functionalist grounds.
Functionalism And Qualia: Do Qualia Exist?
However, Shoemaker allows for the possibility of inverted qualia. He describes a possible case where we could detect that someone’s qualia had shifted. Normally we think it is impossible to detect such shifts.
In summary, the argument depends on the idea that we sometimes have difficulty distinguishing closely related pairs of shades. For example, they are, perhaps, on the blue/green boundary.
Imagine someone’s phenomenological experience on seeing blue became exchanged with what previously they had experienced when seeing orange. Then they would now find it easier to distinguish shades on what is still, in the world and for the rest of us, on the hard to pick out blue/green boundary. If this thought experiment is coherent, it eliminates a Wittgenstein problem. That is that qualia inversion would be undetetectable from behaviour and thus a meaningless claim for Wittgenstein. Thus Shoemaker gives the objection its maximum force by admitting that inverted qualia are possible.
Shoemaker’s defence of functionalism uses the problematic disconnect discussed above. This disconnect is between the phenomenological character of mental states and their function. He admits that for a successful defence, phenomenological characters must be integrated with the functional framework. This comes down to the claim that phenomenology must have a function.
Certainly, that claim is not implausible. It could be that we have qualia to motivate us. If I felt nothing when putting my hand in the fire, my motivation to remove it would be lessened. I would damage my body. This is why leprosy and conditions like CIPA are so dangerous.
Functionalism And Qualia: Summary
Finally, Shoemaker’s argument devolves to the following. There can be a qualitative belief that one is in a state having some propositional content. That content quantifies over qualitative states but does not refer to particular qualitative states. Such qualitative beliefs are functionally definable.