Once upon a time, in a small country by the sea, at the highest point of its highest castle, atop two thrones adorned with precious metals, there lived a King and a Queen. Theirs was a long and blessed reign: their people lived in good health, at peace with their neighbors, enjoying brief winters, generous summers and abundant harvests. But all fortunes must eventually change, and in time, the small country by the sea was ruled only by a King.
The bereaved King lived in mourning, sat alone and draped in dark, funerary colors. But as the years whitened his beard and tugged his jowls earthward, there came a time when the court, noting his childlessness and nervous at the prospect of an empty throne, broached with him the difficult subject of remarriage. The kingdom held lavish Balls and opulent feasts in the hopes of arranging a new match. Many noble houses competed to see one of their own crowned Queen, but in the end, the King could not bring himself to choose a new suitor, and glumly dismissed them all. The Queen’s throne remained empty, and the whole kingdom lamented. The depths of despair are often fertile soil for new ideas, and so it was that the Chief of the Royal Guild of Engineers came forward with a proposal of a very different sort.
She offered to build an heir for the King. It was to be unlike anything which had come before, a being of chrome and silicon; wise, tireless and immortal. The King accepted, and work began. A year passed, during which time the Guild’s factory worked without respite. Acrid smoke poured from its chimneys; the din of hammers and bellows rang throughout the city; and the glow of its lamps and furnaces illuminated crowds which pressed all around, hoping to glimpse the molten zygote of the new Prince. When the child was ready, it was presented in a grand ceremony to the King2, who was pleased. The Guild were as skilled in the craft of flattery as they were in metallurgy, and so it was beautiful, rendered in chrome and gold, with starlight behind its eyes, and bore the mixed likeness of the King and his late wife.
But more marvelous than the look of the child, were its speech and motion. Its voice was melodic, its pronouncements sage, and its movements were as delicate as they were precise. All the kingdom looked on it with pride. But as the years drew on, and the Prince made the castle its home, the King found himself plagued by an unsettling thought. He watched as his successor played, learned and grew, and in his mind the thought grew in parallel. Just what was this creature, to which he would one day entrust his kingdom? Did a mind dwell in the maze of wires behind the chrome child’s scintillating eyes? Or was it a dead thing, eating without hunger, moving without desire, and speaking without thought.
Eventually the King could stand his uncertainty no longer, and made the long pilgrimage by winding rivers and towering cliffs to Delphi. There, he posed his question to the Oracle: how can I know, he asked, whether my heir has a mind, or is a mere machine? She sat quietly for a moment, wreathed in tendrils of pungent incense, then gave her response: “You will have the answer to your question, when you can tell me the width of a headache.” The King pondered this riddle as he made the return journey, and on arriving at his Palace summoned two of the most brilliant minds in the kingdom.
First came the head of the School of Psychologists, followed soon after by the most senior member of the Royal Society of Neuroscientists. The King relayed his conversation with the Oracle: what, he demanded to know of them, is the width of a headache? Naturally, there was some grumbling from the scholars, who pointed out that this was the 8th century and the King should really have come to his scientists first, rather than trusting drug-addled clairvoyants to provide sensible insights into the nature of minds. But they were eventually forced to concede that neither of them had an answer, either to the Oracle’s question, or the larger question of the chrome prince’s mind. The psychologist protested, not unreasonably, that though headaches may have widths, such questions had never been his remit. He was interested in headaches, to be sure, but in their subjective character, how we get them and get rid of them, and how they dispose us to think, feel and act. In his work, a headache is a thing that just *is*, a black box which exists in causal relation to other things and the world, but isn’t explained in language which would be familiar to a chemist or a microbiologist. He wasn’t in the business of studying mental life at the level of physical stuff, so the question of what a headache is in terms of physical concepts, was not one he could answer. That, surely – and at this he turned to the neuroscientist with a slight smirk – was a question for his colleague. Then it was the neuroscientist’s turn to give an unsatisfying answer. She explained that though her science was a natural science – and so dealt in the material concepts of the natural world like charge, frequency and width – headaches were not a part of that linguistic sphere. She could ask a subject questions about their mental life while scanning their brain, and in doing so sometimes identify physical goings-on which correlated with features of that inner life – the parts which light up when they are happy, and so on.
But knowing the neurons which fire when a head is in pain is not the same thing as knowing what pain is, any more than you can know what value is by studying the material qualities of paper banknotes. Neuroscience has, she explained, no real place for the word ‘headache’ in the story which begins with a bump on the head and ends with the arm reaching for an aspirin. Perhaps the head *is* hurting, but when she peers inside the brain, she sees only an electric symphony of firing neurons, not the feeling of pain. As the day drew on, more scholars were summoned to give their accounts. Each was posed the Oracle’s question, but none was able to answer it. With each sigh or shake of the head, their divisions were thrown into starker relief. To join the psychologist came the thinkers of the human sciences; economics, sociology, anthropology. They could deliver sermons in the language of the mind, and filled their books with talk of thoughts, beliefs, desires, and their sister concepts. But they could not offer a material account of these things – of what, exactly, a headache is as an arrangement of physical stuff. Then there were the natural scientists; a great swarm of physicists, chemists, biologists, geologists, and engineers, who filed in to stand behind the neuroscientist. Like her, they spoke fluently in the language of the natural world, setting out with rulers and scales to understand the universe in terms of physical concepts. But each was mute on the topic of mental life. None saw a place for headaches in their explanations of the universe, any more than they saw one for imps and fairies. At hearing all this, the King, who had until now been silent, wondered aloud (and in fouler language than mine) what good their sciences could be, if they couldn’t make sense of so simple an idea as the width of a headache. One side knew about headaches, the other about widths, but nobody could bridge the linguistic rift and pose the Oracle’s question in words which their science could make sense of. None could say what it meant for a jumble of atoms to feel pain. Dejected and impatient, the King returned to Delphi and begged for another audience with the Oracle. He marched up to where she sat, on a dais lit by sunbeams, and accused the gods of tricking him with an impossible question.
This, as it turned out, was a slight severe enough to earn their indignation. The Oracle’s lips moved, and the voice of Apollo emerged: “That is a serious accusation.” The King relayed the testimonies of his scientists, that for all they could tell, the question was nonsense. If, he reasoned, we cannot ask sensical material questions about minds, like how wide or heavy or pink they are, then they must be immaterial things. Pain, like the number four or the concept of liberty, has no width, no physical presence in the world, and so the question was a trick. Apollo’s answer came in the form of another riddle: “Do atoms have a physical presence in the world?” The King feared yet more travel and fruitless exchanges with academics, but much to his relief, this time the god did not wait for an answer. “Nobody has ever seen an atom,” Apollo continued. “They are too small. All we see is a footprint, a beep on a measuring machine here, the buffeting of a pollen grain there, a set of causes and effects which somebody one day pointed to and said “let’s call that an ‘atom’. This is all it really means to *be* a physical thing, to sit as a node in the causal web of other physical things, influenced by them and influencing them in return. For what would be the difference between a world made of physical atoms, and a world made of non-physical entities which did all the same things? If water really boils thanks to angels hiding in the kettle, after all, then angels hiding in the kettle are really just heat.” The King pondered for a moment. “But surely not everything with causal powers is a physical thing? What of abstract things, like businesses or governments? You can’t touch or feel a government, and they certainly don’t have widths, and yet they can affect and be affected by goings on in the natural world. When I need taxes, I tell the government, and when the government shows up at your door, you pay it taxes. Cause and Effect.” “Ah,” replied Apollo, “but there is no mystery there. A government can influence the world and be influenced in return because the word ‘government’ is just a label we apply to a great assemblage of physical entities – politicians, bureaucrats, police officers – who act together in concert. The government may collect taxes, but it is the tax man, not the abstract concept of the State, who rings the doorbell. The parts may exist in constant flux, but without any parts, the government would, like that of ancient Babylon, be only an idea or a memory. So as far as cause and effect go, a government just is the sum of those parts, just as an ocean wave just is a rhythmic disturbance of water molecules. “ With this, the King was forced to agree, but confessed he didn’t see the point.
Apollo went on: “To be a material thing is to nudge the world, and be nudged back in return. If the mind, then, is an immaterial thing, how do we make sense of its connection to the world? When you believe there is a fly on your nose and desire its absence, your arm moves to swat it. When you consume food, hunger is sated. Mind and material. Cause and effect. Now, you might be tempted to wonder whether the mind, like a government or a water wave, is just a convenient linguistic stand-in for some underlying system of moving parts. If you want to make a wave machine, after all, you don’t cast about for something which can generate the abstract concept of a wave, you find a way to make water move rhythmically, which is really the same thing. But what, in the case of the mind, is that underlying system? This is the question your scientists struggled to comprehend, let alone answer, which is what makes minds very different to governments and water waves, whose physical reality is easy to understand. The science of brains has no thoughts on minds, and the science of minds has little to say about brains. If we could answer this question, and say with confidence what moving parts were sufficient to create a mind, then this whole discussion would be moot, and the task of building one would be much simpler. But we do not, and so the mind resists efforts to sweep it under the carpet in this way. “So you want me to believe the mind is a material thing,” mused the King, a note of despair creeping into his voice, “an object in the material world, but one which doesn’t appear anywhere in scientific accounts of it. So where do we find it? What is the width of a headache?” The Oracle shrugged: “It needn’t have been the width of a headache; it could just as easily be the charge density of a belief, or the volume of a desire. The point is, that if your goal is to arrange matter so as to create these things, you must have some idea of how these things result from arrangements of matter; how nerves become nervous. Only then will you be able to look at the chrome child, and know whether it is everything it purports to be. You were right to suspect that this question matters. A competent zombie may not make for a bad king, but the chrome prince will not be the last of its kind, and when they are subjects as well as administrators, then you will have to know how to treat them. As ever, philosophy must keep apace with technology.
But where you went wrong, was to imagine that this is a question which science alone can answer. If you want to make a machine pump water or fly to the moon, for that you need only science. But to make a machine appreciate beauty, or understand ideas, or feel a headache, for all this you need something additional: you need to understand what all these words mean. You need to understand what minds are.” The King paused for a moment, lost in thought. “I don’t suppose there’s an answer to my question hidden in this thicket of riddles?” The Oracle chuckled dryly. “There are some wrong answers. But no right ones, as yet. Not a very satisfying response, perhaps, but the best I can do under the circumstances. In any case, this is really a question for you humans to answer. We made you guys, this next lot is all on you.”