Journey · 10 stops
The Riddle of Consciousness
From the cogito to the “hard problem”.
Stops
Stop 1 of 10: Meditations on First Philosophy
How does consciousness fit into a physical world? Descartes sharpens the problem: the mind is a thinking thing, the body an extended thing – two substances of entirely different kinds. Certainty begins with the mind, while the body becomes a machine. But how can something without extension move an arm?
Stop 2 of 10: Correspondence with Descartes
Princess Elisabeth of Bohemia put exactly this question to Descartes in 1643: how can an immaterial soul, which neither touches nor is extended, set the body in motion? His reply – that the union of soul and body is known through everyday experience rather than clear concepts – did not satisfy her; it would be easier, she wrote, to grant the soul matter and extension. Her objection became the classic problem of dualism, and the question never quite went away.
Stop 3 of 10: On the Soul (De anima)
Much earlier, Aristotle had offered a way out worth recalling here. In On the Soul, the soul is not a second thing inside the body but its form – what makes a living body alive and active, as sight is to the eye. Against Plato’s soul that survives the body, he treats body and soul as one. Twentieth-century critics of Descartes will rediscover this view.
Stop 4 of 10: The Concept of Mind
Ryle attacks Descartes head-on: to look for the mind as an extra thing behind behavior is a category mistake – like a visitor who sees the colleges and libraries and then asks where the university is. Talk of the mind is talk of abilities and dispositions. The ghost in the machine is exorcized, which raises a new question: could a machine have such abilities?
Stop 5 of 10: Computing Machinery and Intelligence
Turing, in 1950, makes that question testable. Instead of asking whether machines can think, he proposes an imitation game: if a machine converses in writing so that we cannot tell it from a human, what grounds have we to deny it intelligence? Behavior becomes the yardstick, much as with Ryle – and the computer a candidate model of the mind.
Stop 6 of 10: Hilary Putnam
Hilary Putnam turns that model into a theory. In 1967 (“Psychological Predicates”, later reprinted as “The Nature of Mental States”) he argues that pain is not one particular brain state, as the identity theorists U. T. Place and J. J. C. Smart had proposed, but a functional state – defined by what causes it and what it causes – that could be realised in very different materials, in an octopus or a machine. Functionalism became for decades the leading view in philosophy of mind and cognitive science; Putnam himself later gave it up. What it leaves out, critics soon said, is how it feels from the inside.
Stop 7 of 10: What Is It Like to Be a Bat?
Nagel puts that inside view at the center, against behaviorist and physicalist accounts alike. A bat perceives the world by sonar; we might know everything about its brain and still not know what it is like to be a bat. Consciousness has a subjective character that objective, physical description seems bound to miss. From now on, every theory of mind must say what it does with experience itself.
Stop 8 of 10: Minds, Brains, and Programs (The Chinese Room)
Searle attacks the computer model from another side with his Chinese Room. Someone who follows a rulebook to answer questions in Chinese can convince outside observers without understanding a word. That is all a program does, he argues: it manipulates symbols by their form, while meaning – and mind – require causal powers at least equivalent to those of brains, whatever they are made of. Passing Turing’s test is not enough.
Stop 9 of 10: Consciousness Explained
Dennett answers Nagel and Searle at once. There is no central stage in the brain where everything comes together for an inner observer – the “Cartesian theater” is an illusion; instead, many parallel drafts are continuously edited. Consciousness can be explained functionally, and the sense of a further mystery is itself something to explain. Not everyone is convinced.
Stop 10 of 10: The Conscious Mind
Chalmers, building on Nagel, separates the “easy” problems – how the brain processes information and steers behavior – from the hard one: why any of this is accompanied by experience at all. A zombie, physically identical to us but without inner life, seems conceivable – and therefore, he argues, possible. From Descartes’ two substances to Chalmers, each new answer has reshaped the riddle; whether it will be solved, dissolved or remain is still open.
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