My model of the mind is that certain cognitive processes cause certain behaviors, but I say nothing about experience itself because assertions of that nature would contribute nothing to what we can observe experimentally, so I consider the nature of experience to be unknowable. Physicalism makes the link between cognition and behavior as well but then goes on to extraneously assert that our description of experience is equivalent to the cognitive processes associated with behaviors which imply experience, such as someone verbally expressing their seeing the color red. The idea of a sensation of red and the idea that there is a pattern of neurons activated by a certain signal from the optic nerve that causes people to do certain things are different from one another descriptively. With what can we show these two descriptions to be referencing the same thing when the answer to the question of the relationship between the two descriptions would contribute nothing to what can be observed experimentally? If cognition and experience are the same thing, we're observing a cognitive process causing a behavior. If cognition and experience are two different things, we're still observing a cognitive process causing a behavior. This is why nothing, in my opinion, can be said about the nature of experience.