Functionalism, Daniel Dennett and the Place of Consciousness
“Explaining everything a system does is not the same as explaining why there is someone there to do it.”
To say that a system does what a conscious person does is not the same as saying that it is conscious. The distinction seems trivial until one notices that much of contemporary philosophy of mind, and much of today’s enthusiasm about artificial intelligence, rests on the wager that there really is no difference: that consciousness is nothing more than a set of well-organised functions, and that any system, biological or artificial, that fulfils them has just as much right to be called conscious as we do.
Who was Daniel Dennett?
Daniel Dennett (1942–2024) was one of the most influential philosophers of mind of recent decades. A professor at Tufts University for almost his entire career, he devoted much of his work to defending an uncomfortable thesis: that consciousness, as we usually imagine it — an inner theatre where something watches what happens — is a useful illusion the brain manufactures about itself. In his best-known book, Consciousness Explained (1991), he proposed the so-called multiple drafts model: the mind has no central place where all information converges, but rather many parallel, competing processes that the brain later narrates as though a unified experience had existed from the outset. For Dennett, asking what it feels like to be a bat, or an artificial intelligence, starts from a mistake: it assumes there is a residue — the so-called qualia — that the functional description leaves out. He maintained that no such residue exists, that fully explaining the function is fully explaining the mind, with nothing left over.
Functionalism: the thesis behind the argument
The idea that mental states are defined by their causal role rather than by their material composition predates Dennett, going back above all to Hilary Putnam in the 1960s. Its most-cited consequence is multiple realisability: if what makes a state pain is its role (it arises from harm, produces avoidance, is reported as unpleasant), then that role can be fulfilled by a brain made of neurons, a brain made of silicon, or, in Ned Block’s thought experiment, an entire nation of people communicating by telephone and organised as though they were neurons. The substrate stops mattering; only the functional architecture matters. If this is correct, nothing in principle prevents an artificial system, given the right organisation — integration of information, a model of itself, the capacity to report its own states, flexibility in the face of novelty — from acquiring whatever it is that matters morally in a mind. The material would, then, be irrelevant in itself.
Cracks in the argument
Functionalism has not convinced everyone. John Searle proposed the Chinese Room: a man who does not know Chinese receives symbols in Chinese and, following a rule book, produces the correct responses in Chinese without understanding a single word. He fulfils the function perfectly, and yet there is no understanding anywhere in the system. Frank Jackson proposed the case of Mary, a scientist who knows every physical fact about colour but has always lived in a black-and-white room: when she finally sees red for the first time, she learns something no textbook of physics had taught her. And then there is the philosophical zombie, which raises the possibility that a system might fulfil every function without anyone experiencing anything at all. None of these arguments has decisively defeated functionalism, but they all point to the same suspicion: that defining consciousness as function might be, more than an explanation, an elegant way of dodging the question.
A risk that is not purely academic
There is an uncomfortable consequence of functionalism that is rarely mentioned outside philosophy seminars. If a being’s moral status depends on its fulfilling certain functions — reporting internal states, integrating information, having a model of itself — then human beings who do not fulfil those functions, whether temporarily or permanently (an unborn child, someone in a deep coma, a person with advanced dementia), are left, by the very same criterion, in an ambiguous zone. Taken to its conclusion, functionalism cannot clearly distinguish between failing to detect someone’s function and that function simply not existing, and that ambiguity does not stay on the page: it has real consequences for medical, legal and social decisions.
The Christian perspective
The Christian tradition raises here a fundamental objection, not merely an alternative metaphysics. Genesis 1:27 and Genesis 2:7 affirm that human dignity comes from an act of God prior to any function: man is the image of God and recipient of the breath of life before he is able to report a single internal state or solve a single novel problem. If this is so, function does not found the person; the person, already constituted by God, is subsequently capable of certain functions. The order matters: to invert it, as functionalism does, leaves the dignity of anyone whose function is absent, damaged or yet to develop without stable foundation.
Paul writes in 1 Corinthians 2:11 that there is a spirit of man, an interior spirit, that knows a person’s own thoughts; Scripture takes for granted, without needing to argue the point, that there exists an inner subject distinct from observable behaviour — precisely what Dennett called an illusion. The Christian faith cannot accept that reduction without giving up one of its most basic affirmations: that there is someone, not merely something, behind every human face, and that this someone does not depend on being able to prove it functionally.
This does not mean that the Christian faith settles the technical debate over multiple realisability, or over whether an artificial system might one day integrate information in the way a brain does. It means something more modest: that a person’s dignity was never, in the first place, at stake because of their function, and that no description of what a system does, however complete, exhausts the question of whether there is someone there to do it.
Conclusion
Functionalism asked philosophy of mind a legitimate question: why should the material matter if the function is identical? The Christian response does not deny that the question is legitimate; it denies that function, whatever it may be, can on its own found what makes someone someone. Dennett was right about something: much of what we call conscious experience can be described, with remarkable precision, in functional terms. But describing is not always founding. Doing is not the same as being, and that difference — which functionalism prefers to dissolve — is exactly where the Christian faith stands its firmest ground.
