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The “standard approach” in clinical neurology has been accused of suffering from an implicit “behaviorist epistemology” because disorders of consciousness are typically diagnosed on the basis of a lack of behavior. All the gold standard diagnostic assessment programs such as the JFK-Coma Recovery Scale are behavioral in nature insofar as they are expressly looking for behavior or the lack of behavior, either motor behavior or verbal behavior. If the behavior occurs appropriately in response to the command or stimulus then they get points that accumulate towards “normal” consciousness. If no behavior is observable in response to the cue then they don’t get points and are said to have a “disorder of consciousness”.
The problem with this approach is both conceptual and empirical. Conceptually, there is no necessary link between behavior and consciousness because unless you are Gilbert Ryle or Wittgenstein you don’t want to define consciousness in terms of behavior. That is, we don’t want to define “pain” as simply the behavior of your limbs whenever your cells are damaged, or the disposition to say “ouch”. The reason we don’t want to do this is because pain is supposed to be a feeling, painfulness, not a behavior.
Empirically, we know of many cases where behavior and consciousness can be decoupled such as in the total locked-in state where someone’s mind is more-or-less normal but they are completely paralyzed, looking for all intents and purposes like someone in a deep coma or vegetative state yet retaining normal brain function. From the outside they would fail these behavioral assessment techniques yet from the inside have full consciousness. Furthermore we know that in some cases of general anesthesia there can be a complete lack of motor response to stimulation while the person maintains their conscious awareness.
Another problem with the behaviorist epistemology of clinical diagnosis is that the standard assessment scales require a certain level of human expertise in making the diagnostic judgment. Although for most scales there is high inter-rater reliability it nevertheless ultimately comes down to a fallible human making a judgment about someone’s consciousness on the basis of subtle differences between “random” and “meaningful” behavior. A random behavior is just that: a random, reflexive movement that signifies no higher purpose or goal. But if I ask someone to squeeze my hand and they squeeze it, this is a meaningful sign because it suggests that they can listen to language and translate a verbal command to a willed response. But what if the verbal command to squeeze just triggers an unconscious response to squeeze? Sure, it’s possible. No one should rule it out. But what if they do it 5 times in a row? Or what if I say “don’t squeeze my hand” and they don’t squeeze it? Now we are getting into what clinicians call “unambiguous signs of consciousness” because the behavior is expressive of a meaningful purpose and shows what they call “contingency”, which is just another way of saying “appropriate”.
But what does it mean for a behavior to really be meaningful? Just that there is a goal-structure behind it? Or that it is willed? Again, we don’t want to define “meaning” or “appropriateness” in terms of outward behavior because when you are sleepwalking your behavior is goal-structured yet you are not conscious. Or consider the case of automatic writing. In automatic writing one of your hands is capable of having a written conversation and writing meaningful linguistic statements without “you” being in control at all. So clearly there is a possible dissociation between “meaningful” behavior and consciousness. All we can say is that for normal people in normal circumstances meaningful behavior is a good indicator of normal consciousness. But notice how vacuous that statement is. It tells us nothing about the hard cases.
So in a nutshell the diagnosis of disorders of consciousness has an inescapable element of human subjectivity in it. Which is precisely why researchers are trying to move to brain-based diagnostic tools such as fMRI or EEG, which are supposed to be more “objective” because they skip right over the question of meaningful behavior and look at the “source” of the behavior: the brain itself. But I want to argue such measures can never bypass the subjectivity of diagnosis without going full behaviorist. The reason why brain-based measures of disorders of consciousness are behaviorist is simply because you are looking at the behavior of neurons. You can’t see the “feelings” of neurons from a brain scanner anymore than you can see the “feeling” of pain from watching someone’s limb move. Looking at the brain does not grant you special powers to see consciousness more directly. It is still an indirect measure of consciousness and it will always require the human judgment of the clinician to say “Ok, this brain activity is going to count as a measure towards “normal” consciousness”. It might be slightly more objective but it will never be any less subjective unless you want to define normal consciousness in terms of neural behavior. But how is that any different from standard behaviorism? The only difference is that we are relying on the assumption that neural behavior is the substrate of consciousness. This might be true from a metaphysical perspective. But it’s no help in the epistemology of diagnosis because as an outside observer you don’t see the consciousness. You just see the squishy brain or some representation on a computer screen. I believe there is a circularity here that cannot be escaped but I won’t go into it here (I talk about it in this post).
I’ve been playing with chrome’s Lucidchart.
Panpsychism is the view that everything has a mental life. Many people find this implausible because it seems weird to think that rocks and dust bunnies are cognizers in the same way that people or animals are cognizers. Panpsychism also seems to contradict the growing consensus among neuroscientists who claim that consciousness only “arises” when a certain level of cortical connectivity or information integration is present in the brain, especially in fronto-parietal circuits and other “global workspaces”.
But why think you need a sophisticated network of cortico-cortical activity in order to have a mind, to have a point of view on the world? Why not think a single neuron is a locus of mental experience? Perhaps there is a faint “something-it-is-like” from the point of view of individual neurons. I call this view neuronal panpsychism: it says that every neuron has a distinct mental life independent of its interaction with any other neuron. Of course a neurons experience is going to be significantly impacted by its causal and reciprocal interaction with neighboring neurons but the point is that the neurons themselves are loci of experience in virtue of their intrinsic nature.
But how do we account for the reams of data suggesting that a high-level of connectivity is necessary for what Stan Dehaene calls “conscious ignition”? After all, even coma patients have some preserved neuronal activity but no one thinks they are conscious: they show no external signs of consciousness at least.
The key to explaining this data in a way that’s consistent with neuronal panpsychism is the “nesting” solution. The idea is that the “macro” consciousness of normal human adults is actually composed of the “micro” experiences of all the individual neurons. The feeling of global unity is therefore an illusion according to neuronal panpsychism. The feeling of being one great unified stream of experience is actually an aggregate of billions of microexperiences in the same way that a river is composed of countless water atoms.
But what does it mean for experiences to “add up” in this way? Is there an equivalent of multiplication or taking the integral? These are tough, unresolved theoretical issues facing all brands of panpsychism. But is it any less mysterious than saying consciousness “arises” whenever informational connectivity reaches a certain threshold in frontal-parietal circuits or when there is 40z synchrony or whatever?
I actually think though neuronal panpsychism can make sense of why it feels different to have your frontal-parietal circuits activated or deactivated and why these circuits seem to make both a significant phenomenal and functional difference to the “macro” level experience of normal human adults. Neuronal panpsychism says that all neurons have mental states but that doesn’t mean they all have the same kind of mental states. For example, a motor neuron might have a different experience than a Von Economo neuron, or a cerebellar neuron might have a different experience than a neuron than lives in the prefrontal cortex.
In effect neuronal panpsychism is a kind of microfunctionalism where neurons with different functional profiles have different mental lives. These functional differences arise from both their phylo and ontogenetic history i.e. different types of neurons have different inherited genetic programming but they also have unique, individualized learning experiences.Thus. the differences in felt macro experiences when there are high levels of frontal-parietal activity are due to the unique experiences of those neurons being added to the choir of subcortical neurons. But they are not the origin of phenomenality, only the “loudest” phenomenality or “most famous” phenomenality, to borrow a metaphor from Dan Dennett’s “fame in the brain” theory (which is an intellectual precursor to neuronal panpsychism).
Thus, when a vegetative patient is transitioning to the minimally conscious state and onwards to normal consciousness there is never one unique threshold when consciousness gets “turned on”. Consciousness is not all or nothing. Consciousness is not a special property of only a unique set of cortical circuits in mammals with sufficiently activated global workspaces. According to neuronal panpsychism, ALL neurons contribute to what-it’s-like to be a unified mind or “I”.
But why stop at neurons? Why not think glial cells have mental lives too? Indeed, why not claims all cells have mental lives? This would be “cellular panpsychism”. But that’s another post.
You might be wondering why this blog has recently downgraded to a series of quotes from random books I’m reading, but I want to assure you: it is not for lack of writing! Rather, as is typical during the summer, I am throwing almost of my writing energies into my Qualifying Paper, with a smidgen left over for emails, tweets, and fluffy blog posts (like this one!). To give you a flavor of the project monopolizing my scholarly willpower, the current but highly tentative title for the paper is “A Genealogical Defense of Normative Nihilism”. And if you can’t tell by the dreary and pompous title, yes, it is highly ambitious paper, perhaps too ambitious, a perennial problem for my philosophical projects. I can’t help it though. I loathe the idea of writing a paper that only moves a nanometer forward in conceptual space. I want to leap, not crawl.
Of all the beings that are, presumably the most difficult to think about are living creatures, because on the one hand they are in a certain way most closely akin to us, and on the other are at the same time separated from our eksistent essence by an abyss…Because plants and animals are lodged in their respective environments but are never placed freely in the clearing of being which alone is ‘world,’ they lack language. But in being denied language they are not thereby suspended wordlessly in their environment