A reference to Max Bennett and Peter Hacker in one of the articles I reviewed last time prompted me to read more.
Now that I’ve finished Neuroscience and Philosophy, I’m compelled to write just one more article about the assaults on neuroscience mounted by philosophers and the like. This is the last one of these for a while. I promise.
Neuroscience and Philosophy (N&P, hereafter) is the book form of a conference debate between Max Bennett and Peter Hacker, on one side, and Daniel Dennett and John Searle, on the other.
The essence of the dispute: Is it right to say that consciousness happens in the brain, that the brain thinks and feels? For language philosopher Hacker and neuroscientist Bennett, the answer is an unqualified “No.” For Dennett and Searle, it’s a qualified “Yes.”
N&P is not new, having been published in 2003, but it’s new to me, and, like the “brave new world” of Miranda, it’s full of strange creatures.
The strangest is the idea that, if I don’t have the words to describe a reality adequately, that reality doesn’t exist. “You taught me language, and my profit on’t is, I know how to curse.” And what Bennett and Hacker curse is the “nonsense” of ascribing the behaviours of entire persons to their various parts, especially their brains.
As a book, N&P has the flaws of its enthusiasms. Bennett and Hacker (B&H) get both first and last word, with Dennett and Searle (D&S) sandwiched in the middle. As a courtroom procedure, it leaves much to be desired. First, the prosecution argues. Then the defense responds. And then the prosecution hones its argument in light of the response. And then nothing, for the defense gets no second turn. Curious, but effective if you go into the project with a mind to make the criticisms of neuroscience seem as strong as possible.
For me, at least, the tactic didn’t work. I went into the book on the D&S side, and despite the best efforts of B&H, that’s where I came out again at the end. Let’s look at some of the reasons why.
Granted, some of the points made by B&H, like their criticism of “hard” reductionists who appear to separate brain and body in suspiciously Cartesian ways, are both reasonable and justified. But their central contention, that language codifies existence, and therefore anything for which we have no coherent language doesn’t exist — yes, that’s a crudish paraphrase, but what else does their argument mean? — is entirely unconvincing.
A very short summary of B&H’s position: Considered conceptually, “ascription of psychological attributes to the brain is incoherent” because “a human being is a psychophysical unity” and not “a brain embedded in the skull of a body.” Therefore, “it makes no sense to ascribe such psychological attributes to anything less than the animal as a whole.” The fact is that “the brain and its activities make it possible for us—not for it—to perceive and think, to feel emotions, and to form and pursue projects.” Thus, they argue, “it is an error, a conceptual error, to suppose that perception is a matter of apprehending an image in the mind” or of “the production of a hypothesis,” or “the generation of a 3-D model description.”
Now, so far there may be claims with which to disagree, but at least B&H’s ideas remain within the scope of the subject at hand. Unfortunately, their justification for their position has nothing to do with empirical investigation or experimental data. Instead, it has entirely to do with the “rules” of language: “How can one investigate the bounds of sense? Only by examining the use of words. Nonsense is generated when an expression is used contrary to the rules for its use.”
In other words, philosophical determination of the “sense” a sentence makes voids any empirical outcomes that cannot be expressed according to their version of the rules that govern the words with which the results are reported and interpreted.
Curious, isn’t it? A book that includes — in error, in my view, but more on that later — a stern criticism of neuroscience as a species of neo-Cartesian dualism (brain v. body) insists on the dominance of the conceptual over the actual.
What would it be to observe whether a brain sees something—as opposed to observing the brain of a person who sees something. We recognize when a person asks a question and when another answers it. But do we have any conception of what it would be for a brain to ask a question or answer one?
Therefore, they argue, “the organs of an animal are parts of the animal, and psychological predicates are ascribable to the whole animal, not to its constituent parts.”
Surely there must be cogent rebuttals of this very abstract criticism? Two of them are included in the book. Daniel Dennett, whose book Consciousness Explained is one of the explicit targets of N&P, takes the first turn.
Dennett characterizes Hacker’s insistence on the supremacy of language over empiricism as a “comically naive” stance, one that is “for all the world like an old-fashioned grammarian scolding people for saying ‘ain’t’ and insisting you can’t say that! to people who manifestly can say that and know what they mean when they do.”
It’s John Searle’s turn next.
To a devotee of Wittgenstein like Hacker, unless you are pointing at the behaviour of an observable entity, you aren’t really pointing at anything. Searle writes that, according to this view, “the language game that we play with the mental words requires publicly observable behavioral criteria for their application.”
In this way, Searle writes, “they confuse the behavioral criteria for the ascription of psychological predicates with the facts ascribed by these psychological predicates, and that is a very deep mistake.” The mistake is that ” Bennett and Hacker do not distinguish, between an argument that the brain cannot be the subject of psychological verbs and the argument that it cannot be the locus of psychological processes.” And, Searle asserts, “once they deny that mental processes occur in the brain, I believe they are unable to give a coherent account of the location and causation of consciousness.”
Searle asks, “Why do we need to postulate a self as something in addition to the sequence of our experiences and their anatomical realization?”
In his view, “there is just the embodied brain and the experiences that go on in that brain.” Searle accepts that there is a “self,” but he calls it “a purely formal postulation.” He writes that “it is not an additional entity. It is a kind of principle of organization of the brain and its experiences.”
Searle objects that “many of the crucial questions we need to ask in philosophy and neuroscience would be outlawed by their approach.”
For example, the central question in vision, “How do neurobiological processes, beginning with the assault of the photons on the photoreceptor cells and continuing through the visual cortex into the prefrontal lobes, cause conscious visual experiences?” could not be investigated by anyone who accepted their conception.
How do B&H respond to these criticisms? Remember, the book gives them a second turn!
Their first retort is to restate their central point: “If a form of words makes no sense, then it won’t express a truth. If it does not express a truth, then it can’t explain anything.”
Arguing that “human beings are not their bodies,” Hacker reiterates the idea that there is a thing called a “person” that performs the actions that take place inside the body that is part of that person. “The brain is a part of the living human being, as are the limbs. It is not, however, a conscious, thinking, perceiving part—and nor is any other part of a human being. For these are attributes of the human being as a whole.”
There is a remarkable disconnect here between the philosopher’s and the neuroscientist’s way of using similar words and expressions. I think that most neuroscientists would have a lot of trouble with the idea that “the brain is not an organ of consciousness.” In fact, it seems exactly backwards to write that “one sees with one’s eyes and hears with one’s ears,” since all of the empirical evidence shows that visual and auditory perception do not become what we normally call “seeing” or “hearing” until the physical inputs of the eyes and ears are processed in the brain. And it seems equally strange to write, in the same sentence, “but one is not conscious with one’s brain any more than one walks with one’s brain.” Does this mean that there is some physical entity called “self” that is of the same kind as those physical entities called “legs”? That can’t be right, not when B&H are so dead set against dualism!
B&H make this case very dogmatically:
It is not the cerebral cortex that sees, but the animal. It is not the brain that moves closer to see better, looks through the bushes and under the hedges. It is not the brain that leaps to avoid a predator seen or charges the prey it sees—it is the perceiving animal.
Fine, it’s the perceiving animal. What is that? An embodied, embedded brain, right? What else could that animal be?
It gets worse when they argue, in response to the example of phantom limb pain, that “the location of a pain is where the sufferer points,” even when that location itself is “an illusion.” Are they really saying that pain felt as coming from a severed limb is really coming from that absent body part?
And if real pain can come from an unseen location, according to their own argument, why then do they insist that “by contrast, thinking, believing, deciding, and wanting, for example, cannot be assigned a somatic location”?
Here’s just how convoluted and frankly incomprehensible they’re willing to get to defend the idea that language without observed behaviour is nonsensical:
That the amputee’s pain is real but its felt location is illusory (his leg does not hurt, as he has no leg) does not show that when a person who has not suffered an amputation feels a pain in his leg, its felt location is illusory too. It really is his leg that hurts!
Got that? I sure don’t. I feel once again like the android Norman on the TV series Star Trek: “Please explain. Only human beings can explain their behavior.” Or, in this case, only language philosophers can explain their contentions.
And I’m not even entirely sure about that.