David Chalmers
Named the 'hard problem' of consciousness; argues virtual worlds are real.
15 videos analysed · 65 quotes checked word for word · updated 2026-10-19
Key facts
- Born in Sydney in 1966, he took his PhD at Indiana University under Douglas Hofstadter and teaches at New York University. Wikipédia 2025 · David Chalmers
- He co-founded PhilPapers, the online database of philosophy articles, with David Bourget. Wikipédia 2025 · David Chalmers
- In 1998 he bet neuroscientist Christof Koch that the neural basis of consciousness would not be found within 25 years. He won the bet in 2023. Wikipédia 2025 · David Chalmers
Positions
click a row to see the evidenceIn Reality+ (2022) he writes that he considers himself an atheist, and that even an all-powerful simulator-creator would not be a god because no being is worthy of worship.
- Even if a simulator created our world, he would not call it a god: he says he still refuses to worship it, because no such being seems worthy of worship. Video 2022 · Reality+: Virtual Worlds and the…
If a being created our simulated world, wouldn't that being be God?
He says no: even a simulator would not be a god for him, since no being is worthy of worship, and he still calls himself an atheist.
In Reality+ he accepts that we might be in a simulation but rejects the step from there to "nothing is real": the objects in such sceptical scenarios are real, which makes scepticism harder to get started, and we can at least know the structure of reality.
His 1996 book argues for property dualism: consciousness is a fundamental property not reducible to physical ones. He is neutral on substance dualism and has some sympathy for panpsychism, which he sees as an alternative to it.
1996 The Conscious Mind argues that zombies are conceivable, so consciousness is not explained by physical facts alone. Wikipédia 2025 · David Chalmers
2013 Says his views have developed rather than changed: he is now more open to interactionism and less sympathetic to epiphenomenalism. He is slightly more pessimistic about the 'combination problem' of panpsychism. Article 2013 · On the Problem of Consciousness…
- Zombies are conceivable: a world physically identical to ours but with no experience makes sense. If it is possible, then physical facts alone do not settle consciousness, and materialism is false. Video 2026 · David J. Chalmers: The Conscious…
- Physical science explains structure and function, the easy problems. Why all that processing comes with a felt experience is a further question, the hard problem. Video 2026 · David J. Chalmers: The Conscious…
- Mary the colour scientist knows every physical fact about red and still does not know what it is like to see it. No purely structural description of an experience is complete. Video 2025 · David Chalmers, Can There Be a…
- Consciousness is the first datum to explain, so it cannot be dropped as an illusion. Splitting it into parts only turns one hard problem into three. Video 2013 · David Chalmers - Why is…2
- So he treats consciousness as fundamental, like mass or space, and looks for basic laws linking brain processes to experience. Panpsychism is one option he finds attractive. Video 2016 · Consciousness and the Universe.…2
Consciousness is an illusion: we only think we have a hard problem to explain.
He calls illusionism a respectable program and proposes the meta-problem (why we think we are conscious), but says consciousness is the first datum to explain.
Neuroscience will explain consciousness away, as science explained away other old ideas.
He answers that there is a core of agreed phenomena (blindsight, neural correlates) and the beginnings of a science, and that splitting consciousness into parts does not make the hard problem go away.
Defends : The hard problem of consciousness and zombies, Mary, the scientist who has never seen red
In a 2019 interview he says he is sympathetic to compatibilism: moral responsibility can make sense even in a deterministic universe.
- For him, moral responsibility is tied to conscious agents: a zombie would have at best a thin kind of responsibility. Video 2016 · Consciousness and the Universe.…
- Yet consciousness need not play a direct role in every moment: very well-practised, automatic actions can still carry responsibility, as the actions of a conscious agent. Video 2016 · Consciousness and the Universe.…
Our brain acts before we are aware of it, so conscious choice cannot be what makes us responsible.
He says consciousness need not play a direct role in every moment: some very well-practised, automatic actions, where the role of consciousness is unclear, can still carry moral responsibility.
If every act is the result of earlier causes, nobody is truly responsible.
On objective morality he goes back and forth. Consciousness may carry some objective value (pain is bad), while much value comes from our own acts of valuing.
Asked about the meaning of life, he says it is where we find it: conscious creatures can invest the world with meaning, in physical and digital worlds alike. He also says consciousness is at least part of the ground of all value.
- Consciousness is at least part of the ground of all value: a universe of zombies would have no value or meaning. Video 2022 · David Chalmers on Virtual Worlds…
- Conscious creatures can invest their world with meaning, so meaning is where we find it. Video 2022 · Reality+: Virtual Worlds and the…
If we live in a simulation, our lives are fake and do not really matter.
He argues that even in a simulation the world and our lives are still real and still matter.
No sourced position yet on: Source of knowledge, Faith and reason, Human nature.
On the big questions
Does God exist?Atheism
Calls himself an atheist in Reality+.
- Even if a simulator created our world, he would not call it a god: he says he still refuses to worship it, because no such being seems worthy of worship. Video 2022 · Reality+: Virtual Worlds and the…
If a being created our simulated world, wouldn't that being be God?
He says no: even a simulator would not be a god for him, since no being is worthy of worship, and he still calls himself an atheist.
Does life have a meaning?A meaning to create
Meaning is where we find it: conscious creatures invest their world with meaning.
- Consciousness is at least part of the ground of all value: a universe of zombies would have no value or meaning. Video 2022 · David Chalmers on Virtual Worlds…
- Conscious creatures can invest their world with meaning, so meaning is where we find it. Video 2022 · Reality+: Virtual Worlds and the…
If we live in a simulation, our lives are fake and do not really matter.
He argues that even in a simulation the world and our lives are still real and still matter.
Are we free?Free without absolute free will
Sympathetic to compatibilism, stated in the 80,000 Hours interview.
- For him, moral responsibility is tied to conscious agents: a zombie would have at best a thin kind of responsibility. Video 2016 · Consciousness and the Universe.…
- Yet consciousness need not play a direct role in every moment: very well-practised, automatic actions can still carry responsibility, as the actions of a conscious agent. Video 2016 · Consciousness and the Universe.…
Our brain acts before we are aware of it, so conscious choice cannot be what makes us responsible.
He says consciousness need not play a direct role in every moment: some very well-practised, automatic actions, where the role of consciousness is unclear, can still carry moral responsibility.
If every act is the result of earlier causes, nobody is truly responsible.
Is the mind the brain?The mind is not matter
Property dualism: consciousness is a fundamental feature of the world, not a by-product of matter.
- Zombies are conceivable: a world physically identical to ours but with no experience makes sense. If it is possible, then physical facts alone do not settle consciousness, and materialism is false. Video 2026 · David J. Chalmers: The Conscious…
- Physical science explains structure and function, the easy problems. Why all that processing comes with a felt experience is a further question, the hard problem. Video 2026 · David J. Chalmers: The Conscious…
- Mary the colour scientist knows every physical fact about red and still does not know what it is like to see it. No purely structural description of an experience is complete. Video 2025 · David Chalmers, Can There Be a…
- Consciousness is the first datum to explain, so it cannot be dropped as an illusion. Splitting it into parts only turns one hard problem into three. Video 2013 · David Chalmers - Why is…2
- So he treats consciousness as fundamental, like mass or space, and looks for basic laws linking brain processes to experience. Panpsychism is one option he finds attractive. Video 2016 · Consciousness and the Universe.…2
Consciousness is an illusion: we only think we have a hard problem to explain.
He calls illusionism a respectable program and proposes the meta-problem (why we think we are conscious), but says consciousness is the first datum to explain.
Neuroscience will explain consciousness away, as science explained away other old ideas.
He answers that there is a core of agreed phenomena (blindsight, neural correlates) and the beginnings of a science, and that splitting consciousness into parts does not make the hard problem go away.
Defends : The hard problem of consciousness and zombies, Mary, the scientist who has never seen red
The question on the site: all the argumentsWho am I, really?My consciousness, my memory
On mind uploading, he prefers gradual uploading that preserves consciousness as the best way to keep existing.
- Given the philosophical uncertainty about uploading, the safest way to keep existing is gradual uploading that preserves consciousness at each step. Video 2016 · Consciousness and the Universe.…
An uploaded copy of you would only be a copy, not you.
He says that, given the philosophical uncertainty, gradual uploading while staying conscious is the best way to keep existing.
Can a machine think?Thinking is computing
He has argued for computational functionalism: what matters is what a system does, not what it is made of, so silicon could be conscious. He thinks today's language models are probably not conscious, but future ones could be.
- He rejects the idea that consciousness needs carbon-based biology. What matters is what a system does, not the stuff it is made of. Video 2026 · Philosopher David Chalmers asks:…2
- The gradual neuron-replacement argument: swap neurons one by one for silicon parts and consciousness has no reason to fade. He calls it perhaps the strongest argument for AI consciousness. Video 2026 · David J. Chalmers: The Conscious…2
- Today's language models are probably not conscious, but none of the obstacles looks insuperable, so future ones could be. Video 2026 · Philosopher David Chalmers asks:…
- Evidence for universal theories of consciousness is weak, so he would test AI through introspective reports, our best evidence for consciousness in humans. Video 2026 · David Chalmers: Tests for…
A program only shuffles symbols without understanding, so it can never be conscious.
He says what matters is what a system does, not what it is made of, and gives the gradual neuron-replacement argument: swap neurons for silicon parts one by one and consciousness seems to stay.
Only a living being can think or feel, and a machine is not alive.
He rejects the view that consciousness needs carbon-based biology and sees no reason why silicon chips could not support it.
See 1 more objections
Chatbots only imitate conversation, so why take the idea of AI consciousness seriously?
He agrees that today's language models are probably not conscious, but says no requirement for consciousness looks like an insuperable obstacle for their successors.
Is the world real?Virtual is real too
Virtual worlds are genuine realities; if we were in a simulation, things would still be real.
- Something is real if it makes a difference, if it has causal powers. Virtual objects do, so they are not illusions. Video 2022 · Reality+: Virtual Worlds and the…2
- Simulations need not be illusions: in a perfect simulation the world around us would be real, just made of a different kind of stuff. Video 2024 · “Virtual Reality Is GENUINE…
- He answers Putnam: someone in a simulation who says « I'm in a simulation » would speak truly, since their words are not tied to the base reality. Video 2024 · “Virtual Reality Is GENUINE…
- He admits we can hardly rule out being in a simulation, but says this undercuts neither the reality nor the meaning of our lives. Nozick's objections to the experience machine do not apply to VR, where you make your own choices. Video 2024 · “Virtual Reality Is GENUINE…2
A brain in a vat could not even say it is in a vat, so the sceptical worry defeats itself.
He says words like computer or simulation are not anchored to base reality, so Putnam's reply does not work against the simulation hypothesis.
Nobody would want to live in a machine that gives pleasant experiences: real life is better.
He says this objection does not apply to virtual reality, where you make your own choices and can live a meaningful life.
See 1 more objections
A simulated thing is only an illusion, not a real thing.
He argues that virtual objects have causal power and are not illusions, even if a virtual Obama is not the real Obama.
Defends : Even in a simulation, the world would be realMixed : The simulation argument: three possibilities, one of which is true, What if I were just a brain in a vat?
The question on the site: all the argumentsIn their words
I do not think any being is worthy of worship.
Zombies are conceivable so possible and therefore materialism is false
my view, by contrast, is that simulations need not be illusions
consciousness is the basis of value it's at least part of the ground of all value
1 more quotes
Consciousness is a fundamental property of the universe
How the ideas evolved
Click a step for details1995The 'hard problem' of consciousness
His paper 'Facing Up to the Problem of Consciousness' separates the 'easy' problems (how the brain processes information) from the 'hard' one: why there is any experience at all.
1996The Conscious Mind: property dualism
His first book argues that physical zombies are conceivable and that consciousness is a fundamental property, linked to the physical world by natural laws.
1998The Koch bet and the extended mind
With Andy Clark he publishes 'The Extended Mind'. The same year he bets neuroscientist Christof Koch that the brain basis of consciousness will not be found within 25 years.
2011Is your phone part of your mind?
In a TEDx talk he applies the extended mind thesis. If a phone does the job biology does, it counts as part of the mind. Denying it, he says, is brain chauvinism.
In their words« If the metal does the same job the biology is doing, that would also count as part of the mind »He argues the mind can extend beyond the skull: a phone can be part of the mind, and denying it is brain chauvinism. watch
« it doesn't matter whether it's stored somewhere deep in your brain or out there in the world »The extended mind thesis: memories stored outside the brain still count as part of the mind if they drive your states. watch
2013More open to interactionism
Looking back at his 1996 book, he says he now explores interactionism, which he had opposed, and that he is slightly more pessimistic about panpsychism's combination problem.
2016Drawn to panpsychism
He says the view he is attracted to is that consciousness is present at a fundamental level in all physical processes. He states the main difficulty, the combination problem: how small bits of experience add up to one unified experience. He says nobody has a solution yet.
In their words« Consciousness is a fundamental property of the universe »He says consciousness is a fundamental property, like mass, and calls himself a naturalist: explanation has to stop somewhere. watch
« I'm inclined to think that conscious agents are really the fundamental loai both of moral worth »On free will, he links moral responsibility to conscious agents: zombies would have at best a deflated kind of responsibility. watch
« it's not obvious to me though that there needs to be a direct role of consciousness in the moment for that kind of free will »He thinks some unconscious, well-practised actions can still carry moral responsibility. watch
2018The meta-problem of consciousness
He asks why we think there is a problem of consciousness at all. He treats illusionism as one of the best reductionist theories, though he finds it implausible.
2019Panpsychism and idealism taken seriously
In a long 2019 interview he says he is committed to taking panpsychism seriously. A later chapter on idealism judges cosmic idealism about as promising as any version of panpsychism.
2022Reality+: virtual worlds are real
His book argues that virtual reality is genuine reality and that we could be in a simulation without it being a lesser world. He gives a rough 10 to 20 percent credence that we are.
2023Could a language model be conscious?
He judges it somewhat unlikely that current language models are conscious, but thinks successors could be serious candidates within about a decade. In June 2023 he wins his bet with Koch.
2025A mathematical theory of consciousness?
He is attracted to the project of mathematising consciousness, but says no purely mathematical description of an experience can be complete, as Mary's room shows. He finds integrated information theory not especially plausible.
In their words« I think there are very big obstacles to that but I'm very attracted by um the program of mathematization »He is not always in favour of physicalizing consciousness, finding big obstacles, but is attracted to a mathematical theory of consciousness. watch
« I don't find the IIT especially plausible myself. I think the evidence for it is weak »He finds integrated information theory not especially plausible, though a good example of a mathematical theory of consciousness. watch
« She still won't know what it's like to see red »He uses Mary's room to argue that no purely mathematical description of an experience can be complete. watch
2026The Conscious Mind at 30, and AI
Looking back at his 1996 book, he restates the conceivability argument against materialism. He notes that if the common view is right, we have already built behavioural zombies. He thinks current language models are probably not conscious, but that no requirement for consciousness looks insuperable for future ones, and he proposes tests based on introspective reports.
In their words« I very much reject that view. I don't think it's the stuff that matters. I think somehow it's what it does »He rejects the view that consciousness requires carbon-based biology: what matters is what a system does, not what it is made of. watch
« I'm inclined to think the current language models are not conscious, but I think the case for future language models being conscious is not that easy to rebut »He thinks today's language models are probably not conscious, but takes the possibility of conscious future models very seriously. watch
« I'm very much not a behaviorist about the mind »While using behavioural notions of quasi-belief for AI, he stresses that what happens inside, consciousness, is crucial for many purposes. watch
The arguments 7
The site's arguments they defend or criticize, and why. Click a title to see the full argument.
His own argument: zombies are conceivable, so physical facts do not explain experience.
Defends 'virtual realism' in Reality+: virtual objects are real objects.
Calls Bostrom's simulation argument clearly worth taking very seriously, and gives a gut credence of maybe 10 to 20 percent.
Takes the simulation hypothesis as the modern form of Descartes' sceptical scenarios, but argues that being in a simulation would not make the world unreal. Answering Putnam's brain-in-a-vat argument, he says someone in a simulation who says "I'm in a simulation" would speak truly.
He uses Descartes' point: I can doubt the world, but not that I am conscious right now. Consciousness is our primary datum.
He uses Mary's room to argue that no purely mathematical description of an experience can be complete: she still will not know what it is like to see red.
Answering Nozick's experience machine, he says its objections do not apply to virtual reality, where you make your own choices and can live a meaningful life.
Allies and opponents
Frank JacksonClose
Collaborated with Frank Jackson on two-dimensional semantics.
Nick BostromSparring partner
Takes Bostrom's simulation argument seriously, while arguing a simulated world would still be real.
Daniel DennettDisagrees
Dennett was among the critics of his 1995 paper, and accused his property dualism of being epiphenomenalist; Chalmers rejected that.
John SearleDisagrees
Searle criticised his views in the New York Review of Books in 1997; Chalmers replied.
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All sources (48)
- David Chalmers Wikipedia · 2025
- On the Problem of Consciousness and the Nature of Philosophy: An interview with David Chalmers Filosofisk supplement · 2013
- #67 – David Chalmers on the nature and ethics of consciousness 80,000 Hours · 2019
- Reality+ (p. 144), quoted in 'An Australian philosopher's fascinating argument against God' Chalmers, Reality+ (W. W. Norton); quoted on Substack · 2022
- Reality+: Virtual Worlds and the Problems of Philosophy Publishers Weekly · 2022
- A 25-Year-Old Bet about Consciousness Has Finally Been Settled Scientific American · 2023
- Could a Large Language Model be Conscious? arXiv / Boston Review · 2023
- The meta-problem of consciousness Journal of Consciousness Studies (ANU research portal) · 2018
- News from the Consciousness Beat (quoting Chalmers on idealism) Hamlet's Chimera (Substack) · 2023
- The Matrix as Metaphysics consc.net · 2003 *
- Reality + or – 3 Quarks Daily · 2022 *
- Is your phone part of your mind? | David Chalmers | TEDxSydney YouTube (TEDx) · 2011
- David Chalmers - Why is Consciousness so Mysterious? YouTube (Closer To Truth) · 2013
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016
- Hard Problem of Consciousness — David Chalmers YouTube (Serious Science) · 2016
- Episode 25: David Chalmers on Consciousness, the Hard Problem, and Living in a Simulation YouTube (Mindscape) · 2018
- Reality+: Virtual Worlds and the Problems of Philosophy (David Chalmers) YouTube (The Michael Shermer Show) · 2022
- “Virtual Reality Is GENUINE Reality" | David Chalmers Mindfest Lecture YouTube (MindFest) · 2024
- David Chalmers, Can There Be a Mathematical Theory of Consciousness? | Natural Philosophy Symposium YouTube · 2025
- Philosopher David Chalmers asks: When we talk to AI, what are we talking to? YouTube (UC Berkeley) · 2026
- Philosopher David Chalmers asks: When we talk to AI, what are we talking to? YouTube (UC Berkeley) · 2026
- David J. Chalmers: The Conscious Mind at 30. Looking back and looking forward YouTube · 2026
- David Chalmers: Tests for Consciousness in AI Systems YouTube · 2026
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016
- Reality+: Virtual Worlds and the Problems of Philosophy (David Chalmers) YouTube · 2022
- Reality+: Virtual Worlds and the Problems of Philosophy (David Chalmers) YouTube (The Michael Shermer Show) · 2022
- David Chalmers on Virtual Worlds and the Problems of Philosophy | Closer To Truth Chats YouTube (Closer To Truth) · 2022
- “Virtual Reality Is GENUINE Reality" | David Chalmers Mindfest Lecture YouTube (MindFest) · 2024
- Reality+: Virtual Worlds and the Problems of Philosophy (David Chalmers) YouTube (The Michael Shermer Show) · 2022
- David Chalmers on Virtual Worlds and the Problems of Philosophy | Closer To Truth Chats YouTube (Closer To Truth) · 2022
- Reality+: Virtual Worlds and the Problems of Philosophy (David Chalmers) YouTube (The Michael Shermer Show) · 2022
- David J. Chalmers: The Conscious Mind at 30. Looking back and looking forward YouTube · 2026
- David J. Chalmers: The Conscious Mind at 30. Looking back and looking forward YouTube · 2026
- Episode 25: David Chalmers on Consciousness, the Hard Problem, and Living in a Simulation YouTube (Mindscape) · 2018
- David Chalmers Discusses the Hard Problem of Consciousness YouTube (StarTalk) · 2024
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016
- “Virtual Reality Is GENUINE Reality" | David Chalmers Mindfest Lecture YouTube (MindFest) · 2024
- “Virtual Reality Is GENUINE Reality" | David Chalmers Mindfest Lecture YouTube (MindFest) · 2024
- “Virtual Reality Is GENUINE Reality" | David Chalmers Mindfest Lecture YouTube (MindFest) · 2024
- David Chalmers on Virtual Worlds and the Problems of Philosophy | Closer To Truth Chats YouTube (Closer To Truth) · 2022
- David Chalmers on Virtual Worlds and the Problems of Philosophy | Closer To Truth Chats YouTube (Closer To Truth) · 2022
- David J. Chalmers: The Conscious Mind at 30. Looking back and looking forward YouTube · 2026
- David Chalmers: Tests for Consciousness in AI Systems YouTube · 2026
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016
- David Chalmers, Can There Be a Mathematical Theory of Consciousness? | Natural Philosophy Symposium YouTube · 2025
- Episode 25: David Chalmers on Consciousness, the Hard Problem, and Living in a Simulation YouTube (Mindscape) · 2018
- Consciousness and the Universe. Interview with David Chalmers YouTube · 2016