Jun 10 2008
Consciousness is undoubtedly one of the most complex and interesting phenomena in the universe. Wrapping our minds around the concept of mind has vexed philosophers and scientists for centuries – perhaps because it is the task of the brain trying to understand itself. This has led to many theories and bizarre beliefs about consciousness – that it is non-physical, that it is due to quantum weirdness, or that it requires new laws of nature to explain. And yet modern philosophers and neuroscientists are increasingly of the opinion that perhaps it’s not such a hard problem after all. Perhaps the real trick is realizing that it’s not even a problem at all.
Yesterday I wrote my most recent reply to Michael Egnor’s rather lame attempt at defending what is called cartesian dualism – the notion that consciousness requires the addition of something non-physical. Ironically he invoked the writings of David Chalmers to his cause, not realizing (or not caring) that Chalmers is a harsh critic of cartesian dualism and rather supports what he calls “naturalistic dualism.” Chalmers believes that the “something extra” required to explain consciousness is a new law of nature, not a non-physical spiritus.
Today I will discuss Chalmers’ proposed solution (actually he points the way to a solution but acknowledges he does not yet have one) and its major critic, Daniel Dennett.
The Problem of Subjectivity
At the core of the debate over consciousness is the nature of subjective experience. Why is it that we have subjective experience, that we feel, and we have the sense that we exist? Why aren’t we, as David Chalmers asks, just “zombies” – carrying out all of the processes of life without experiencing it?
Part of the enduring controversy over this question is that it intersects with a deeper question about the nature of science itself. Can science rely upon subjective experience to understand nature? Or (a related question) can science formulate models of reality that include elements that cannot be objectively observed and tested? If we don’t allow subjectivity, then how do we study the phenomenon of subjective experience itself?
I admit this is a thorny problem. Former Buddhist monk, B. Alan Wallace, has written a number of books and articles advocating, for this reason, the reintroduction of subjective experience into scientific thinking. I disagree with him on this point, and also on the way in which he invokes quantum mechanics to support his form of dualism – but this is a topic of a future post (perhaps later this week).
The question of whether or not science should restrict itself to the observable and testable has plagued the world of physics since the time of Einstein and the death of the classical model of nature. In the classical world there was no doubt that what we observe about the world is the same as the way the world actually is. Quantum mechanics put an end to this simplicity.
In the quantum world, elegant experiments have shown us that nature, at its fundamental level, is counterintuitive. Matter exists simultaneously as both a wave and a particle, and the properties of matter can only be described statistically based upon probability – the Heisenberg uncertainty principle, that we can only know so much about the physical properties of matter, laid waste to classical determinism.
This lead to the great question – is quantum mechanics simply a system that accurately describes and predicts what we see during experiments, or does it describe the way nature actually is – and (here’s the really important bit) is there a difference?
Ironically, Albert Einstein revolutionized physics with relativity theory by being the first physicist to say that the variability of time and space is not just a system for explaining observation – it actually describes the way the universe works. Prior to Einstein physicists invoked the ether – an unseen and unknown substance permeating all space and through which light propagated. The ether was a fix to rescue classical physics from the observations of reality. Einstein then, later in life, took the opposite position by resisting the notion that quantum mechanics actually described nature, as opposed to just our experiments. (This is summarized by his famous quip, “God does not play dice with the universe.”) Einstein wanted (but failed) to develop a unified field theory to explain what was really going on (to rescue the classic world he helped destroy), while younger physicists, such as Max Born, argued that what we see is what we get – science must restrict itself to what can be tested and observed.
So What is Consciousness
This same type of dilemma that so vexed Einstein is now faced by philosophers and scientists trying to crack the consciousness nut. Everyone (outside of cartesian dualists) seems to agree that neuroscience is making tremendous progress in explaining what Chalmers calls “the easy problems” of neuroscience – explaining observable, objective, measurable mental phenomena as brain states and function. But neuroscience has not offered an explanation for the subjective experience of consciousness – the “hard problem.” (Chalmers outlines his views in this paper published in 1995.)
Chalmers believes that there is something more that is needed than a reductionist description of brain function. He thinks there is a higher order natural process going on – an actual new law of nature as fundamental as electromagnetism – that explains how brain activity causes consciousness.
I think this is akin to Einstein’s desire to find an underlying unifying theory of physics that would do away with all the apparent quantum weirdness. Chalmers wants to find a “grand unification theory” of consciousness. His imagined new law of nature is his ether of the mind.
Chalmers may ultimately be correct (just as Einstein may ultimately turn out to have been correct – we may yet find some deeper reality underlying quantum mechanics). I cannot think of any reason why Chalmers must be wrong – there may be some higher order process going on. But at this point I find Chalmers’ proposition as unnecessary as the ether.
Further, Chalmers also says that perhaps consciousness arises from some property of nature that science cannot discover, even in principle. This gets back to the argument about the nature of science – do the methods of science tell us how nature is, or just that part of nature that science can test? I believe it must be the latter – untestable notions have no useful place in science. Chalmers’ untestable law of consciousness cannot lead anywhere.
Perhaps the most direct challenge to Chalmers has come from philosophy Daniel Dennett. He has raised a number of excellent points challenging Chalmers’ contention of the hard problem. Particularly revealing is the analogy to vitalism – the notion of a vital life force that separates animate from inanimate objects. He writes:
The easy problems of life include those of explaining the following phenomena: reproduction, development, growth, metabolism, self-repair, immunological self-defense, . . . . These are not all that easy, of course, and it may take another century or so to work out the fine points, but they are easy compared to the really hard problem: life itself. We can imagine something that was capable of reproduction, development, growth, metabolism, self-repair and immunological self-defense, but that wasn’t, you know, alive. The residual mystery of life would be untouched by solutions to all the easy problems. In fact, when I read your accounts of life, I am left feeling like the victim of a bait-and-switch.
This imaginary vitalist just doesn’t see how the solution to all the easy problems amounts to a solution to the imagined hard problem. Somehow this vitalist has got under the impression that being alive is something over and above all these subsidiary component phenomena. I don’t know what we can do about such a person beyond just patiently saying: your exercise in imagination has misfired; you can’t imagine what you say you can, and just saying you can doesn’t cut any ice. (Dennett, 1991, p.281-2)
Therefore the vitalists of old claimed that a vital force was necessary to explain life. Biologists then proceeded to explain all the components of life until nothing was left for vitalism to explain, except a vague sense that being alive is somehow a thing unto itself. Dennett compares this to the dualists (all dualists, including naturalistic dualists like Chalmers) – if neuroscience can explain all of the cognitive phenomena that we can observe: memory, perceptive, communication, reflection, etc., then perhaps it has explained consciousness as well as biology has explained life. Then there would be no more need for a separate explanation for consciousness as there is for a vitalistic force to explain life.
In other words – life is what we collectively call a host of complex and organized chemical reactions resulting in the ability to use energy for growth and reproduction. Life emerges from the component parts that make it up, but there is no extra thing that is life.
Likewise, perhaps consciousness is what emerges when the brain is actively engaged in its various functions. When we are perceiving stimuli, keeping information in our working memory and manipulating it, carrying on an internal conversation with ourselves, etc. – all of these things add up to consciousness without the need for any extra added thing. In this sense consciousness in an emergent phenomenon – not a new law of nature or a bit of mysterious magic. While I admit it is difficult to fully comprehend this notion, I find it the most compelling of all the options.
Chalmers’ primary objection comes down to – why do we experience anything? Why aren’t we zombies – carrying out all the functions we ascribe to consciousness without being conscious. I think the simple answer is – what’s the difference? What if carrying out all the functions of consciousness IS consciousness?
Dennett explains it thusly:
What impresses me about my own consciousness, as I know it so intimately, is my delight in some features and dismay over others, my distraction and concentration, my unnamable sinking feelings of foreboding and my blithe disregard of some perceptual details, my obsessions and oversights, my ability to conjure up fantasies, my inability to hold more than a few items in consciousness at a time, my ability to be moved to tears by a vivid recollection of the death of a loved one, my inability to catch myself in the act of framing the words I sometimes say to myself, and so forth. These are all “merely” the “performance of functions” or the manifestation of various complex dispositions to perform functions. In the course of making an introspective catalogue of evidence, I wouldn’t know what I was thinking about if I couldn’t identify them for myself by these functional differentia. Subtract them away, and nothing is left beyond a weird conviction (in some people) that there is some ineffable residue of “qualitative content” bereft of all powers to move us, delight us, annoy us, remind us of anything.
I also add to this that there are different states of consciousness that correlate with different brain states – not just the function changes, but subjective consciousness changes as well. For example – dreaming is a form of consciousness. You are still yourself and you are aware and many of the components of consciousness are there, but it is also different. One difference is that reality testing (a specific cognitive function) is not as active. That is why often dreams make sense to you while you are dreaming but then to your awake consciousness it seems unreal. Being inebriated is also an altered state of consciousness, as are all so-called encephalopathies where overall brain function is impaired.
In other words, if you change or impair the “easy problem” functional components of consciousness you also change consciousness – the simplest explanation for this is that consciousness emerges from those functional components.
Philosophers and scientists still struggle to put into words exactly what consciousness is, and it does defy easy conceptualization. But I think the best explanation, and one that is consistent will all observable phenomena – both what we can objectively measure, and what we subjectively experience – is that consciousness is an emergent property of all that the brain does. I do not think we need to invoke quantum weirdness, I do not think we need to appeal to unfalsifiable inherent laws of nature, nor non-physical causes.
At least that’s what I think.
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