With his leather jacket and biker's haircut, David Chalmers is about the closest thing philosophy has to a rock star these days. The Australian even has his own barroom party piece, The Zombie Blues, which he is known to perform raucously – accompanied by electric guitar – at cognitive-science conventions.

“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.”

It’s not the sort of tune likely to be included in a Michael Bublé Christmas compilation but it is worthy of mention for acting as an entrée to one of the biggest questions of contemporary science and philosophy: What is consciousness?

Chalmers, who was in Dublin this week for Trinity College Dublin's Donnellan Lecture series, provides a rough answer with today's idea: Any purely physical explanation of consciousness is going
to fail.

Consciousness was once thought to reside in the soul, but today many scientists argue that what we call consciousness is, in fact, an illusion. How do we settle this issue?
David Chalmers: "It's quite commonly regarded as the last great challenge for science. We are getting a pretty good grip from neuroscience on explaining aspects of our behaviour, our responses to the things we do, walking, talking and so on – but those we can call the easy problems, in a certain sense. The hard problem of consciousness is explaining why all that stuff that our brain does is accompanied by subjective experience, why it feels like something from the inside.

“[The American philosopher] Daniel Dennett takes the fairly extreme view that there’s nothing to explain here, that it’s really an illusion: we just need to explain our behaviour. My own view is on the other end of the spectrum to Dennett, which is that there are systematic reasons to think that any purely physical explanation of consciousness is going to fail. Neuroscience is going to give us great explanations of the easy problems, and the behaviours, but it’s always going to take an extra ingredient somehow to get to consciousness.

“So I’ve proposed that we have to ultimately regard consciousness as something like a fundamental element in nature and look for the fundamental principles, analogous to fundamental laws in physics that connect consciousness to everything else.”

Does that mean consciousness exists after death?
"My own view is that there is a strong correlation between consciousness and physical processes, so it's not as if consciousness can be disassociated from them in the way that someone who believes in a soul might go for.

“All the evidence is that, wherever you find consciousness, you find correspondent processes in something like a brain, and if you affect the brain you affect consciousness. In that sense, there are views way further out on the spectrum than mine.”

But who is best-placed to answer the problem? Is it a neuroscientist, a philosopher, or a psychologist?
"It has actually been an extremely rich area over the last 20 years or so, with people approaching it from all these different areas – philosophy, neuroscience, psychology, mathematics, physics, spirituality – which is a big change from say 30 years ago, when there was almost nothing on these topics.

“I suppose the core ones are neuroscience, psychology and philosophy, and we have seen a big three-way interaction between those fields. The results will come from neuroscience and maybe we will get something about a neural correlative consciousness, but you can’t just read the conclusions off the data. I think there is also a role for the philosopher in assessing the reasoning, to see: what have we explained by this framework, and what haven’t we explained?”

Is spirituality also a legitimate line of inquiry?
"Spirituality is a very broad term. The explicitly religious elements have a somewhat more distant connection to the science of consciousness. But there are elements of the spiritual tradition that I think are more directly connected, and here I have in mind especially eastern traditions that have made a practice of studying the mind from the inside by methods such as meditation and contemplation.

“In the history of Buddhist philosophy, you will find some really quite sophisticated claims about consciousness and the character of subjective experience, long before anyone in the western tradition was thinking about these things.”

The Irish philosopher George Berkeley took a different spiritual approach to the issue. Has he something to teach us here?

“Absolutely. Berkeley was a pioneer when it came to the philosophical study of consciousness, and of course he had a very distinctive view of it, which was not just the rejection of materialism but the rejection of matter, in a way.

“Berkeley’s views are making a bit of a comeback recently, especially under the guise of the panpsychist view that underlying the whole physical world is a level of consciousness at the fundamental level of matter, that maybe electrons are ultimately constituted by consciousness, and atoms and molecules.

"For Berkeley, in a way he went for a version of that, [by saying] all that was ultimately constituted by God's mind. In the contemporary versions, God isn't playing so central a role. But take that Berkeley vision and subtract God, and maybe you have got a philosophical idea that is actually being taken quite seriously in contemporary science and philosophy."


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