Continuing on functionalism with David M. Armstrong’s "The Causal Theory of the Mind" (1981).
We reconvened a day after Part One on Putnam to come back with fresh energy, considering Armstrong, who self-consciously presents himself as a defender of science: It's the most likely scientific hypothesis that mental states are physical states of the brain, and it's the philosopher's job to get rid of conceptual tangles that make this identity seem unintelligible. Functionalism is his solution for doing this, specifically a causal analysis of mental concepts. A mental state is that which in us has a certain characteristic cause-effect structure (e.g., hunger causes food-seeking) and involves information-sensitive types of causes: the causes involve belief and perception. These are mappings of the world that are then utilized by purposes.
Armstrong connects the two senses of the word "intentionality." As you may recall, intentionality in the technical sense is the "aboutness" of a mental state, like my perception of a ball is about that ball, and my belief that the ball is red is either about the ball or maybe about the fact that is red or, depending on your account of belief, about the proposition that it is red. And then this gets tricky if I'm hallucinating and there isn't really a ball there, in which case, what is my perception or belief really about? The other sense of intentionality is the everyday sense of having a purpose, and Armstrong's use of the term generalizes it to teleology, i.e., the overall purposefulness of a system.
So it might seem like functionalism as the mark of the mental and intentionality as the mark of the mental are different ideas, but Armstrong combines them: The function of a mental state is its intention, i.e., what it's aiming to get at in some sense, which in the case of a perception is the thing in the world that's being perceived, and in the case of a belief at the state of affairs the believer is trying to believe truly about, and in the case of a desire or purpose about literally getting or achieving something.
Why am I emphasizing this point? Because maybe the most interesting part of this paper insofar as it's different than Putnam's view is its commitment to externalism about mental events. A causal theory means that we explain mental states largely in terms of what causes them, and it's the object of intention that's the (typical) cause of the state: The red ball causes my perception of it, my beliefs about it, and maybe its alluring nature causes me (is one of the causes anyway) to want to grab it and chuck it at your head or whatever.
This is one (probably unsuccessful) way of trying to deflate the hard problem of consciousness, through something like direct realism. Instead of talking about ineffable qualia, we should analyze perceptions as exhausted by their representational contents, by what in the world they're perceptions of. Of course, then there's the problem of illusions, and Armstrong in this paper considers "the secondary qualities." Colors (sounds, smells) are not themselves in the world; they're caused by light of a certain wavelength bouncing off the object toward my eye. So this is a persistent illusion: what seems like a simple perception of red is in fact complex.
This emphasis on causal connections is supposed to connect psychology up to physics, to make talk of the mental properly scientific and so open the way to materialism. Phenomenal properties themselves are not going to play causal roles, but if they're associated with physical things like light or the motion of air (sound) or particles in the air (smell), then those things can serve causal roles instead. So this theory does not deny the existence of qualia, but does deny that they play a role in how we explain the mental. Does the theory explain qualia, then? You decide!
We also consider whether this externalist account means that mental states are merely relational, i.e., dispositions for producing external action (this would verge on behaviorism) or intrinsic. For Amrstrong's use of this to clear the way for physicalism, it has to be the latter: mental states may be analyzed in terms of their relations to other things, but what they actually are intrinsic states of the brain.
End song: "Pain Makes You Beautiful" by Jeff Heiskell's JudyBats, as featured on Nakedly Examined Music #5.