Philosophical zombies are nonsense
Why consciousness can’t exist outside your brain
For centuries, philosophers have wrestled with one of the greatest mysteries of existence: can the conscious experience of the mind be reduced to the physical processes of the brain? Those who argue it cannot often invoke the concept of “philosophical zombies” — hypothetical beings that are physically identical to humans but entirely devoid of conscious experience.
On the surface, this thought experiment seems like a compelling challenge to materialist understandings of consciousness. But a closer look reveals philosophical zombies are an empty threat to physicalism and an example of circular reasoning that assumes the very conclusion it attempts to prove.
The mind and brain: dualism vs. materialism
The debate over the nature of consciousness has long been dominated by two opposing perspectives: dualism and materialism. Dualists claim mental states exist separately from physical states of the brain, while materialists argue mental states are fully reducible to physical processes.
Among materialists, behaviourists analyse mental states in terms of observable behaviour, whereas functionalists take a broader view, defining mental states by their roles within a cognitive system. Functionalism provides a promising framework for understanding consciousness as an emergent property of the brain’s physical states.
Despite this, some philosophers like David Chalmers have attempted to reconcile dualism with scientific naturalism. Chalmers proposes consciousness should be treated as a fundamental property of the universe, much like electromagnetism. But while consciousness is indeed fundamental to our experience, it does not follow that it is a fundamental feature of reality itself. Rather, conscious experience appears to be an emergent property of neurobiological processes, and this conclusion aligns with a materialist understanding of the mind.
The problem of philosophical zombies
To challenge the reducibility of consciousness to physical brain states, Chalmers introduces the notion of philosophical zombies. These beings are “atom-for-atom identical” to conscious humans, but they lack subjective experience. The argument goes that if such zombies are conceivable, then consciousness must be something beyond physical processes and non-reducible to the brain.
At first glance this may seem persuasive. If we can imagine a being that behaves exactly like us but lacks subjective awareness, doesn’t that imply consciousness is something separate from the physical world? Not quite.
The flaw in this argument lies in the assumption that because philosophical zombies are conceivable, they must also be possible in some meaningful sense. This is a textbook example of circular reasoning: the very idea of philosophical zombies presupposes that consciousness is non-reducible, and then uses this assumption as evidence to support the conclusion.
Consciousness as an emergent property
Understanding consciousness as an emergent property of the brain dissolves the apparent mystery posed by philosophical zombies. Consciousness, like other mental states, arises from complex neural interactions. And if this is the case, then any physically identical being would necessarily have the same conscious experience. The idea of a philosophical zombie — biologically identical yet lacking consciousness — is therefore incoherent. The reason no such beings exist is not because they are merely improbable, but because they are impossible.
Consider the example of pain perception. Two individuals might walk barefoot on hot coals, but only one reports feeling intense pain while the other remains unfazed. This difference in experience does not suggest that pain is separate from the brain, rather it highlights individual variations in neurological processing. If conscious experience were truly non-physical, we would expect pain perception to be entirely independent of brain states. But this is not what we observe. Pain, like all other conscious experiences, is influenced by neural activity, reinforcing the idea that subjective experience is rooted in the physical structure and function of the brain.
The hard problem of consciousness
Chalmers famously distinguishes between the “easy” and “hard” problems of consciousness. The easy problems involve explaining how brain functions give rise to behaviour and cognitive abilities like attention, memory, and decision-making. The hard problem, on the other hand, concerns why these processes are accompanied by subjective experience.
While the hard problem may seem intractable, it is likely an illusion created by our own cognitive limitations. We struggle to explain consciousness in purely physical terms because we are embedded within the system we are trying to analyse. Just as a blind person cannot fully conceive of colour, we may be unable to grasp the complete nature of consciousness from within our own conscious perspective. But this limitation does not justify abandoning a materialist framework. If anything, it suggests our understanding of consciousness is merely incomplete, not that it is beyond explanation.
The myth of the cartesian theatre
One of the reasons philosophical zombies seem intuitively plausible is that we often conceive of consciousness in terms of what philosopher Daniel Dennett calls the “Cartesian Theatre.” This model implies that there is a central observer (a “self”) inside the brain, watching mental events unfold on a private screen. But this is an illusion.
Neuroscience has provided ample evidence that consciousness does not reside in any single location within the brain but arises from distributed neural processes. Once we abandon the mistaken idea that consciousness exists as a discrete entity, the explanatory gap between the physical brain and subjective experience begins to close.
The takeaway
Philosophical zombies do not challenge the materialist view of consciousness; they merely restate the assumption that consciousness is non-reducible in a more dramatic form. As our understanding of the brain advances, it is becoming increasingly clear that consciousness, like all other mental states, is grounded in physical processes. The explanatory gap is simply a reflection of the current limits of our knowledge.
Jonathan Meddings is an author and advocate from Melbourne, Australia.
