The topic of the causal efficacy of subjective experience is of interest to me because I struggle with it. As I've said before, it does give us a sense of self and I think that is important in some way but beyond that it's a puzzle to me.
So, here are some critiques of the paper. One is semantic. In the literature and media, we see lots of different terms used for consciousness. As Chalmers points out in his seminal paper
The word ‘consciousness’ is used in many different ways. It is sometimes used for the ability to
discriminate stimuli, or to report information, or to monitor internal states, or to control behavior.
We can think of these phenomena as posing the “easy problems” of consciousness.
The hard problem of consciousness is the problem of experience. Humans beings have subjective experience: there is something it is like to be them
So, terms like "feeling" can be ambiguous. There is a psychological meaning to the term but also a technical one. Are we talking about an easy problem (neural states and responses) or the hard problem (phenomenal experience)? If the focus of the discussion is the hard problem, I think the term "experience" (what it's like) should be used. It avoids confusion.
To illustrate this, we can think of certain neural state configurations that we call a feeling (pleasure, pain, emotion). We categorize these certain states with those terms. Say, for instance, there are certain states in the hypothalamus, hippocampus, amygdala, limbic cortex we categorize as emotions. There is the brain configuration that we have, on the one hand, but we also experience
that brain configuration. There is a "what it's like" to have that configuration — a subjective experience of that state. This would also be like experiencing a thought, a pain, a pleasurable state, a reasoning process, an intuition, etc. The brain states can be thought of as easy problem configurations but experiencing those states is the hard problem.
Here's a thought experiment. Say I'm in bed for a night of sleep. While still awake certain nerve fibers (unmyelinated C fibers or myelinated A-delta fibers) activate and I have a pain. While I'm awake I experience
that activation and take a different position to alleviate it. However, what if I'm in a deep sleep? Those fibers activate and while I don't have a subjective experience of it, I still change position to alleviate it. There is the same behavioral result in both cases. What was casually added to the same situation by subjective experience? It does give me a sense of myself having that pain but is there also something else? This is, of course, the philosophical zombie question that Pinker talks about.
So, this raises the question for evolution. Would evolution not have produced what we see without subjective experience or is there some other reason for subjective experience.