[Ks. jutun suomenkielinen versio.]
Photo: Anna Ovaska. CC BY-NC-ND 4.0.
A pioneer in the philosophy of mind, David J. Chalmers (b. 1966) does not shy away from interdisciplinary questions. The Australian can speak about zombies, quantum mechanics and virtual worlds without batting an eye. The most burning problem, however, is a thoroughly philosophical one: the nature and place of consciousness in the physical world. Even though our understanding of the phenomenon of consciousness is improving bit by bit, progress in the field must be faced with a humble outlook: “Everyone should acknowledge that we are very early in the process and that probably in a 100 years’ time people will look back on the science of consciousness of today and say that we were still struggling in the dark.”
In philosophy, the first step is always to formulate the right questions in the right way. Chalmers became world-renowned after the publication of his 1996 book The Conscious Mind, which differentiated between two sets of research questions. The ‘easy problems’ refer to the psychological functions of the mind: questions of how the brain processes environmental stimuli or integrates information, for example. Even after we answer these questions, we will still be left with the ‘hard problem’, i.e. why do our experiences feel like something in the first place?1
In search of answers, Chalmers turns out to be a methodological pluralist: when trying to solve difficult questions, we need to use the results of empirical sciences in addition to intuition and philosophical arguments. Correspondingly, scientific theories must always be interpreted philosophically. In the interview, Chalmers takes an example from quantum mechanics. According to him, we understand the formal theory of quantum mechanics very well, but nobody seems to understand its philosophical implications. Thus, the importance of interpretation is at the heart of a scientific view of the world. At the same time, Chalmers uses quantum mechanics to find an answer to a question that has plagued him for over two decades: how can non-physical consciousness have a causal role in the physical world? To solve this puzzle we need the help of philosophy, but also of physics and the cognitive sciences.
Chalmers also admits to being quite fond of thought experiments. In a well-known experiment, he imagines zombies who are molecule-to-molecule identical with us and who behave just like normal human beings, but who have no conscious experiences. Chalmers uses this hypothesis about the ‘conceivability of zombies’ to illustrate the ’hard problem’ of consciousness. The point is that we cannot infer just from behaviour or brain activity what something feels like: what the subjective phenomenal experience is like, or whether someone has experiences at all. What is lurking behind these questions is the concept of ‘consciousness’.
Do you think that there is a single definition for consciousness and what could it be?
I do not think there is a single definition for any word in English or probably not in Finnish for that matter. One of the issues is that people often use the word 'consciousness' for different phenomena. But there is one kind of consciousness that I am most interested in, and that is consciousness as subjective experience: roughly what it feels like to be thinking, reasoning, or being. In this sense, a system is conscious if there is something it is like to be that system2. So there is something it is like to be me, and I presume there is something it is like to be you, but there is probably not anything it is like to be this bottle of Pepsi. Likewise, a mental state is conscious if there is something it is like to have that mental state. So when I drink this coffee, it tastes like something, there is something it is like to taste coffee, but maybe there is nothing it is like for my brain to be doing some underlying computations in the background for regulating my heartbeat, let's say. So one is conscious and the other one is not.
So, what can we learn from the conceivability of zombies?
The fact that we can conceive of physical processes without consciousness at the very least seems to suggest that there is a strong epistemological and conceptual gap between physical processes and consciousness. If you can’t wholly explain consciousness in terms of physical processes, that is usually grounds for postulating further primitive principles which are needed to cross the gap; just as James Clerk Maxwell couldn’t explain electromagnetic causes in terms of existing mechanical causes and decided to postulate something as fundamental.3 I see the conceivability of zombies as one of a number of considerations that tend to suggest that you can’t fully explain consciousness in terms of physical processes. And that thereby suggests that we need something new and fundamental in our ontology – and in the science of consciousness.
Have we made the hard problem any easier during the past 20 years?
Good question! I do not think we have solved it. Maybe we have a better sense of what the options are and some possible ways forward. For example, on the non-reductive side there has been a lot of advance in understanding panpsychist options: the pros and cons of postulating consciousness everywhere as a primitive. On the materialist side, there has been a lot of advance in what people call ‘the phenomenal concept strategy’4 for trying to locate the gap between physical processes and consciousness as just a gap between our concepts and not a gap in nature.
It is very common in philosophy that all this discussion does not really produce solutions. There is no more consensus in this field than there is in any other part of philosophy. But at least we can produce some extra understanding and maybe that is what we have been able to do within the philosophy of consciousness. Meantime the science of consciousness has also been developing very nicely: for example the neuroscience and the neural correlates of consciousness. Again I would say it has not produced us a solution to the hard problem. But at least it can show that we can advance the science without actually solving the hard problem. Materialists want something more, which is a reduction of consciousness to something, say, brain. My own view is that such a reduction is not going to happen. So maybe this is the best we can get.
How much value should we give to our folk psychological knowledge and intuitions about consciousness?
I do not think there is any single answer to that question. I mean, our intuitions are what we start with. Intuitions can very easily turn out to be wrong. We just have to examine our intuitions one by one to see what the evidence for this claim is. And some intuitions seem to be on reflection not much supported by evidence: intuitions about whether a mouse is conscious, for example. Maybe that is not something supported by much data.
On the other hand, my intuition that I am conscious is almost more than an intuition. It is an intuition supported by very, very strong evidence that would be very difficult to give up. In philosophy intuitions are just the start of a dialectical process that is always open to an opponent to deny.
Daniel Dennett, for example, has described the self as a ‘center of narrative gravity’5. To what extent do you think we could say that the self is a fiction?
The self is another one of these words that means many different things. I am inclined to think that there certainly are notions of self for which the narrative model seems quite appropriate: the notion of self as the thing with which we identify, the story we tell ourselves about how we could enter the world. This certainly involves narrative, and a narrative will always be a fiction. Sometimes it may be grounded in reality. But it certainly can involve some elements of construction.
At the same time, I am inclined to think that maybe there are notions of the self which are more immutable, and that the subject or self of consciousness is pretty plausible. There is a subject of consciousness here: that is not something that I make up. I do not think I made up my consciousness. I think it exists. There is a self or subject who is having that consciousness: when there is something what “it is like” for me, there probably is something that “it is like” for me, the self, and I do not think that is a fiction or a narrative. It is probably prior to any level of narrative. Although even then there is any number of questions: Am I the same self that I was five minutes ago or yesterday or last year? Maybe it is the same. Maybe some elements of narrative or construction or at least memory construction comes in and integrates all of this over time.
Dennett’s claim seems to be a bit stronger: that the self is a non-entity or an abstraction – or a metaphor – and it could be proven wrong scientifically.
I guess I would not go that far. There are multiple notions of the self. Maybe some of them are non-entities. Maybe some of them do not have a reference in the scientific system, but other ones might well turn out to be quite legitimate.
Limits of Consciousness
Chalmers began his career as a researcher of artificial intelligence. The young mathematician from the University of Adelaide first received a scholarship for postgraduate studies at Oxford in 1987. Finally, he ended up in the United States, at the University of Bloomington in Indiana, where he worked under the supervision of Douglas Hofstadter (b. 1945) in an AI lab. Mathematics came to be replaced by philosophy and cognitive science, and Chalmers received his PhD in 1993.
He says that the possibility of artificial intelligence still fascinates him, but progress in the field has been very slow. He jokes that according to some people a year spent working with artificial intelligence is enough to make one believe in God – so hard has it turned out to be to make it work. Artificial cognition also leads us to the question of the limits of human experience.
You have discussed the concept of the extended mind in your 1998 article “The Extended Mind” with Andy Clark6. But how about consciousness as in phenomenal experience: is it restricted to the brain and the central nervous system, or could it be extended as well, alongside with cognition? So where does consciousness stop and the rest of the world begin?
When Andy and I wrote the article on the extended mind, we were not especially talking about consciousness but about some states of mind such as believing and desiring. We made a case that they can sometimes extend beyond the body; that your phone, for example, can be a repository of your memories and some of your beliefs and so on. But we didn't make this claim about consciousness: we were talking about beliefs of another kind which need not be conscious. For example, I can believe something about the dates of birth of my parents even when I am not thinking about it consciously, because it is stored in my memory, waiting to be consciously triggered, and I think a phone can do something like that.
But can consciousness be extended? Can my phone be somehow a direct constituent of my consciousness? I guess I have never seen any reason to believe that. Yes, some people have been trying to argue that it could be, but as far as I can tell, all the data we have is consistent with the idea that – at least in humans – consciousness depends directly on the brain and only indirectly on the environment. That still leaves open the question of whether consciousness depends just on brains – so, for example, can a fly be conscious, can a computer be conscious, can a smartphone be conscious in its own right? I have at least entertained the hypothesis of panpsychism that says there is some consciousness everywhere, and it is possible for it to extend past the brain.
So you still believe in panpsychism?
“Believe” is a too strong a term. It has always been one of the views, which I think is an interesting possibility on the mind–body problem. I have never come out and said that it must be true. But it is very much worth investigating, and in recent years I have thought about it quite a lot. I tried to mount the best argument I could for panpsychism. Roughly, it is the view that gets to acknowledge consciousness as a fundamental constituent of our world, and to give it a very natural place inside the causal network of physics.
At the same time, it has got these big problems: the combination problem, i.e. how little bits of consciousness – say at the level of particles – come together to form a kind of consciousness that we have as human beings7. I think it is fair to say that nobody has put forward a solution to the combination problem that has convinced many people. So if someone can solve the combination problem, then I would be an enthusiastic panpsychist. As it is, I am still agnostic.
Multi- and Interdisciplinary
In addition to mapping the domain of panpsychism, conceiving of zombies and arguing about property dualism, Chalmers has done many other things as well. His latest book Constructing The World (2012) is an extensive study on epistemology, philosophy of language, metaphysics and philosophy of science8. During the last few years, he has also worked on a model of two-dimensional semantics which aims to depict the meanings of linguistic utterances with the help of possible worlds.
Do you still see yourself mainly as a philosopher of mind, or should we consider the philosophy of mind a broader subject?
I started in the philosophy of mind, I guess. In order to think about consciousness and the philosophy of mind, I very rapidly find myself thinking about metaphysics; thinking about metaphysics I find myself thinking about philosophy of language; thinking about that I find myself thinking about epistemology; then the philosophy of science comes in etc. And in the end we find that everything connects to everything else. So I certainly do not restrict myself to any one area. I suppose I think of myself as first a philosopher of mind – that is where I started, and that is the subject I always come back to. And the problem of consciousness still strikes me as just about the most interesting problem in the world. But over the years it has become for me embedded in a giant web of philosophical issues and that has made being a philosopher very interesting. Because one thing you get to do is to connect working on all these different fields like physics, or the cognitive sciences, or technology, computer science and so on.
You already mentioned physics. Why do you think there is such hype in the philosophy of mind about physics and quantum mechanics? Is there a paradigm shift happening?
When it comes to the problem of consciousness, you are addressing in my view a very fundamental question about the place of consciousness in the physical world and one needs to think very hard about the character of the physical world. Physics is our best guide to the physical world. Quantum mechanics is very, very puzzling in its own right. It is one part of nature that we do not understand, and it actually has got some suggestive connections to consciousness. So those potential connections are very much worth pursuing.
I also think that some ways of connecting consciousness and quantum mechanics are better than others. For example, if you are looking for a causal role for non-physical consciousness in the physical world, people often say “well, physics rules this out” because it is causally closed. But in the field of quantum mechanics it is actually very far from clear. There are processes such as the collapse of the wave function, and in fact they leave some room open for consciousness9. This should be carefully examined both by philosophers and physicists to see where it leads us.
What could be the next hard problem?
Meet the new boss, same as the old boss; meet the new hard problem same as the old hard problem10. I do not think the hard problem of consciousness is going away anytime soon. So maybe that is the new hard problem. Also, there are many hard problems: the problem of interpreting quantum mechanics is as hard as any problem in the world. The problem of why the universe exists and why it has any character. Every philosophical problem is hard. I just think the problem of consciousness is particularly hard.
You mentioned technology before. How about the problems concerning virtual worlds?
There are various versions of virtual reality, and various views on whether virtual reality has the same [ontological] status as non-virtual reality. Say that we are in a matrix. Is that somehow less real? Is it an illusion like Descartes’ evil demon, or is it reality?
I think virtual reality is about as good as ordinary reality, and as people start spending more and more time in virtual reality, maybe that is a conclusion that we will quite naturally get used to. I do not think the problems here are as hard as the hard problem of consciousness, but they are worth thinking about. It has a lot of bearing on philosophical issues about scepticism as well as about the relationship of the human mind and the world. I am actually now writing a book on those topics: virtual reality, scepticism, space and structure. I am trying to combine all that into a coherent worldview.
Do you want to say something more specific about those topics?
I wrote an article about the hypothesis that “we are in a matrix” and what is standardly regarded as a sceptical hypothesis: if we are in a matrix, none of what we ordinarily believe about the world is true11. There are tables and chairs and so on, but it is all an illusion. But my view is that it is not an illusion. If we are in a matrix, there are still tables and chairs. They just have a somewhat surprising nature: they are made of computations underneath, or made of bits, you might say, which is surprising, but not really more surprising or weird than them being made of quantum mechanics.
Notes & Bibliography
- 1. See e.g. David J. Chalmers, The Conscious Mind. In Search for a Fundamental Theory. Oxford University Press, New York 1996, xi–xii.
- 2. Chalmers adapts Thomas Nagel’s (b. 1937) famous definition according to which: ”the fact that an organism has conscious experience at all means, basically, that there is something it is like to be that organism.” Nagel also characterizes this as ”the subjective character of experience”. See Thomas Nagel, What Is It Like to Be a Bat? The Philosophical Review. Vol. 83, No. 4, October 1974, 435–450.
- 3. Differential equations that describe the behavior of electromagnetic fields are commonly known as the Maxwell equations. Scottish physicist James Clerk Maxwell (1831–1879) created the basis for electromagnetism by showing the connections between electrical and magnetic phenomena.
- 4. See e.g. Daniel Stoljar, Physicalism and Phenomenal Concepts. Mind and Language. Vol. 20, No. 2, 2005, 296–302.
- 5. Daniel C. Dennett, Consciousness Explained. Little, Brown & Company, Boston 1991.
- 6. Andy Clark & David J. Chalmers, The Extended Mind. Analysis. Vol. 58, No. 1, 1998, 7–19.
- 7. See e.g. David J. Chalmers, The Combination Problem for Panpsychism (pdf). Unpublished manuscript; cf. Consciousness and Its Place in Nature. In Philosophy of Mind, Classical and Contemporary Readings. Edit. David J. Chalmers. Oxford University Press, New York 2002, 247–272.
- 8. Oxford University Press, Oxford 2012
- 9. In quantum mechanics, the wave function describes the probability of measuring an elementary particle as being given at a specific point in time at a certain location. The collapse of the wave function means that an elementary particle is actually located or it realizes one of its possible states when its properties, such as its position, are measured. According to some interpretations, the measurement is simply any interaction of a particle with the environment that collapses the wave function. Others, however, think that the collapse requires that a conscious observer registers the measurement. In his presentation at Toward a Science of Consciousness, Chalmers developed a position according to which consciousness triggers or causes the collapse of the wave function. He also speculated with the hypothesis – developed by Roger Penrose (b. 1931) and Stuart Hameroff (b. 1947) – that consciousness is generated when the wave function is about to collapse.
- 10. The Who, Won’t Get Fooled Again (1971). Chalmers is acquainted with rock music also as a singer, songwriter and performer at conferences of philosophy of mind, such as Toward a Science of Consciousness. His philosophical lyrics can be found in The Zombie Blues: I act like you act/ I do what you do/ but I don’t know/ what it’s like to be you/ What consciousness is /I ain’t got a clue / I got the Zombie Blues.
- 11. David J. Chalmers, The Matrix as Metaphysics. In Philosophers Explore the Matrix. Edit. Christopher Grau. Oxford University Press, Oxford 2005.