In this article Patricia Churchland is arguing against David Chalmers' assertion that the physical sciences, including contemporary disciplines like neuroscience, will never be able to explain consciousness. More specifically, they will never be able to explain the hard problem of consciousness: how and why physical processes give rise to subjective experience. Otherwise stated, how and why is it that subjective experience arises from physical processes?
We can contrast the hard problem of consciousness with the easy problems of consciousness. Easy problems of consciousness involve explanations of how cognitive or behavioral functions are performed. Examples include how our brains merge perception of different attributes (e.g., color and shape) which take place in different parts of the brain into a unified perception and how independent processes in the brain combine to produce coherent (behavioral) responses to perceived events, such as verbal reports.
The easy problems are all questions about how our brains discriminate stimuli, integrate information, produce reports, etc... these problems are all about identifying and explaining physical processes. Since these are all questions about how physical systems work, in principle, neuroscience will advance enough to give an explanation.
However, none of these explanation give us any answer to how or why conscious experience arises from these processes. If everything performed by the brain (inputs to outputs) is a closed physical system, why have conscious experience of anything? To further bring out this problem, lets look at the zombie thought experiment...
To illustrate that consciousness might not be necessary for successfully navigating the world, consider the' famous Zombie thought-experiment (pre-dating Chalmers, but famously advocated by him). Chalmers says that we can conceive of beings just like us in every way except they lack conscious experience. They live lives just like ours: walking, talking, driving, eating (mostly brains), discussing philosophy of mind, etc..except they don't experience these things consciously. There is no phenomenal aspect to their lives. They have no qualia.
Consider motion detection and vision. It seems loco to think we could decouple motion detection from phenomenal awareness of what we are seeing. However, there is considerable evidence that we can detect motion without having conscious experience of it! Crazy, I know, but this might be the case. This condition is called "blindsight." There are people who have brain damage in the part of the brain that produces conscious awareness of what we are seeing yet still behave as though they can see! This seems to show that we could navigate through our world without walking into things without having the phenomenal experience of seeing. If this sounds too crazy to be true, check out the video:
Start at 6:50 on this one then from the beginning of the second video.
The main point is this: suppose there are processes/functions that we have which are accompanied by conscious phenomenal experience but that we could perform these same functions just as well without the consciousness (like someone with blindsight). This means that consciousness is just "tacked on" to the process. It doesn't help us perform the task any better or worse (maybe even worse, because there's one more thing to go wrong).
If this is the case, then if we explained the process in physical terms, we'd be left with a "hard problem": why the crap is consciousness added on to this process? Also, since we'd know everything there is to know about the process from a physical point of view, there'd be information about the conscious experience of performing that process that'd be left unexplained by our physical account. Therefore, a purely physical account of the mind is incomplete.
Anyhow, the upshot of Chalmers' position is that since the physical sciences will never be able to give us an answer to the Hard Questions of consciousness, we need to postulate consciousness as a separate fundamental feature of our world, not reducible to physical laws on any level. Just as electro -magnetic forces can't be explained in terms of other physical laws and principles and and are thus considered fundamental forces of the world, so too should we consider the psychophysical laws and principles of consciousness--fundamental and irreducible.
The Hornswaggle Problem: Churchland's Response to the Hard Problem
I think Churchland's article is as close to a rant as you can get in published academic writing. She essentially takes a machine-gun approach to criticizing Charlmers' argument for a distinction between the easy problems and the Hard Problems. Hold on to your hats, we're going on a critical thinking rampage!
Churchland's general approach to opposing the assertion that the is a Hard Problem is to cast doubt on whether this is the right way to conceptualize consciousness. The idea here is that if you misconceptualize a problem, you will make it seem intractable while, in fact, it may not be.
Consider an analogy. Medieval doctors, to explain animation, would ask of the heart, "in which part are the animal spirits concocted?". Of course, if you conceptualize animal spirits as being what causes animated life, asking this question about the heart will seem like an intractable problem. If, however, you ask how much the blood the heart pumps/hour, the problem no longer seems intractable. The point here is that how we conceptualize a problem has everything to do with how solvable it will appear.
Another attack on the Hard Problem is to ask why it is that the line of what can and cannot be solved through the physical sciences is drawn at the particular place Chalmers suggests--rather than somewhere else. Consciousness is a difficult problem, but difficult problems are nothing new to the scientific enterprise.
Why not also include into the Hard Problem the neurological basis for autism and schizophrenia? why we dream when we sleep? how short-term and long-term memory work? how we develop skill acquisition, plan, and make decisions? Why is the dividing line between the Hard and soft problems drawn exactly where it is? There doesn't seem to be any good reason for drawing the line in the particular place it is.
The Left-Out Hypothesis
Chalmers argues that even if we were to solve all the easy problems, their answers wouldn't inform the Hard Problem. But where is the evidence that if we eventually understood all the easy problems that we still wouldn't understand the Hard Problem? (why and how consciousness emerges from those processes). The left-out hypothesis is why would the solution to the Hard problem be "left-out" from our cumulative understanding of all the easy problems? Where's the evidence for this hypothesis? And how many sentences can I end with question marks?
Another implication of the left-out hypothesis is that the Hard Problem frames the issue of consciousness such that current research on consciousness is presumed to fail even before the results are in. But if we accept the demarkation line suggested by the Hard Problem, we must say, before the research runs its course that this line of research will not contribute anything to the problem of consciousness. This conclusion runs counter to what the empirical results suggest. We should be guided by empirical results, not a priori conclusions about what is or is not a solvable possible. Let the science decide!!!
Furthermore, there is strong evidence in current research suggesting that attention, awareness, and short-term memory are very closely connected consciousness. Why shouldn't we think that advances in these areas won't contribute valuable understanding to the problem of consciousness?
Vs The Zombie Thought-Experiment
Recall that the Zombie thought experiment is supposed to show that we can't study consciousness by studying physical stuff: All (or at least some) of our mental/brain functions can possibly work without the conscious experience, therefore, conscious experience and qualia are simply "tacked on" and are fundamentally different "stuff" from physical "stuff". (see Zombie discussion in the intro of this post)
Anyhow, assuming that we've rejected the left-out hypothesis, the only thing still supporting the Hard/easy distinction is the zombie thought experiment. Since the zombie shares all of our behaviors and capacities (minus consciousness), using the physical sciences to explain how all these capacities work would not tell us anything about how and why we have conscious experience of these processes (since consciousness adds nothing to our ability to perform them and the contents of subjective consciousness can't be accessed by the physical sciences).
But accepting the conclusion of the zombie thought experiment relies on the possibility of zombies. Zombies are merely a thought experiment! It seems redonk to draw conclusions one way or another about the limits of science based on a thought experiment about zombies!
For example, imagine a possible world in which gasses do not get hot even though their constituent molecules are moving very quickly. Does your ability to imagine this possibility function as an argument against the empirically verified relationship between temperature and mean molecular kinetic energy? That's just silliness!
Just because we can imagine non-conscious zombies is no argument for the limits of brain science (mmm...brain science!).
Vs Scope of Qualia/Spectrum Argument
The Hard Problem seems to be directed at brain events that are accompanied by qualia. But there doesn't seem to be any consensus as to which types of capacities or functions are accompanied by qualia and which aren't. There are of course obvious cases like the pain you experience when you stub your toe or the blue you experience when you look up at the sky...or maybe even the overwhelming pleasure you feel when you know it's time for philosophy 101.
But there are also areas of dispute. Some people say they have "limb-position" qualia; that is, they have a phenomenal experience of where there limbs are. Others disagree. Do we have quali associated with "what it's like" to move our head? To know which way is up? Do eye movements have qualia? Maybe some movements do and other's don't? What about introspective qualia? Or thoughts?...some seem auditory, others visual, others, like when I do logic problems, don't seem to have any qualia.
When it comes to capacities and functions, is there a continuum for the vividness of qualia that are associated with them? Does it vary from individual to individual? Do some have qualia for a capacity and and other's don't have it? All of these issues cast doubt on a clear demarkation line for the Hard Problem--if there is indeed such a problem. The answer to where to draw the line between the processes that have qualia and those that don't might seem clear when we consider only the prototypical cases of qualia, but these cases represent only a small sub-set of the whole.
The class processes accompanied by conscious experiences is not as well-defined as we might initially suppose. To further confuse matters, there are fuzzy boundaries between attention, short-term memory, and awareness.
Are the Easy Problems Really Easy?
The easy problems are yet to be solved, so why should we suppose their solution is easy? This is pure conjecture. For example, the nature of motor representation is a mystery: a signature is recognizable whether it is written with the dominant or non-dominant hand, the foot, or with a pencil strapped to the shoulder. How can completely different sets of muscles do this when they weren't the muscle groups used to learn the task?
The solution to this problem lacks important--not just minor--details about the concepts of motor control, learning, and information retrieval. On what grounds do we call it an Easy Problem?
The Danger of Drawing a Line
There is a danger of drawing a line at consciousness based on current ignorance. If we rope an area off to certain methods of research before really giving it a good try, then we are writing a self-fulfilling prophesy and blocking off what might have been fruitful research.
Argument from Ignorance
The Hard Problem is an argument from ignorance. That is, the argument moves from a claim that we are currently ignorant about/lack understanding of a phenomenon (consciousness) to the conclusion that the phenomenon will never be understood/explained (using current methods) etc... Specifically, in the context of the problem of consciousness, Chalmers' argument goes like this:
(P1) We do not understand much about consciousness;
(C1) Consciousness can never be explained;
(C2) Nothing science could ever discover would deepen our understanding of consciousness;
(C3) Consciousness can never be explained in terms of physical properties.
But the fact that we know little of a particular phenomenon only tells us that we know little about it! Consider an analogy. Just because I don't know what a flying object is, it doesn't follow that it's an alien space craft. I can only conclude that...I don't know what it is! Not knowing isn't positive evidence for some positive conclusion. We cannot draw substantive conclusion from our lack of knowledge...especially given that modern brain science is still in its infancy.
If brain science had progressed as far as molecular biology has on the transmission of evolutionary traits, we could make a substantive conclusion, but, again, given the pre-pubescent state of neuroscience, all we can reasonable conclude is, we don't know.
Metaphysical vs Epistemological "Mysteriousness"
The fact that a problem appears mysterious is not a fact about the problem or a fact about the metaphysical nature of the universe. It is an epistemological and psychological fact about us! The problem is mysterious to us given the current state of our science. Perhaps, if the state of our scientific understanding of the brain were different, the problem wouldn't be so mysterious.
The history of science is littered with previously "mysterious" problems. Consider the problem of life previously known as "the mysterious problem of life". For millennia the best minds could not grasp how life could emerge from the inanimate matter of cells. "Surely, the physical sciences can't solve this problem!" they said! "There must be magical animal spirits...or something."
The mystery of how life emerges from proteins and sugars was a mystery to be sure, but the mystery was not a property of the problem, but a consequence of the epistemological state of the pre-cellular biology world.
The Argument from Personal Incredulity
The other informal fallacy Churchland accuses Chalmers of is the argument from personal incredulity. It goes like this, "well, I simply cannot imagine how x will be able to explain y." We've been hearing this argument for centuries in regards to everything from thunder to computers that can learn. As far as I know, this type of argument has by and large been on the losing end. I simply can't imagine it being right! ;)
Anyhow, Chalmers' argument seems to--in part--rely on an argument from personal incredulity. He just cannot fathom how the physical sciences could explain consciousness. But that's more a reflection of his epistemological state than it is an argument against the possibility of a scientific solution. Why should we care two hoots about what someone can or cannot imagine when we consider what science may or may not be able to explain?
Again, the history of science give us plenty of examples which were imagined to be too difficult to solve, but ended up having fairly simple solutions, and also examples of problems that were thought easy to solve but turned out to be very difficult.
In short, Churchland argues that when you're in a position of ignorance concerning scientific matters, and the science is still young, we need to do the science and see how it plays out, not make pronouncements about what can a cannot be solved.