But as our post-millennial neuroscientists marvelled at the sparkling, dare I say spectral, patterns cascading from their high-resolution brain scanners, they were nagged by a mischievous question: who’s running the show? How does the brain, with its diverse and distributed functions, come to arrive at a unified sense of identity? “Soul” doesn’t figure in the lexicon of neuroscience, but what about the soul’s secular cousin, “self”? Could we speak of a person’s brain without, ultimately, speaking of the person? Was the self merely the sum of its cerebral parts? The illusion of the ghost in the machine was compelling - the natural intuition that somewhere in the shadows of the brain there lurks an observing “I”, an experiencer of experiences, thinker of thoughts and controller of actions.

This was hard to reconcile with the material facts (the vacant machinery that actually packs the skull) and it was plain to see that the mental operations underlying our sense of self - feelings, thoughts, memories - were dispersed throughout the brain. There was no homuncular assembly point where a little soul-pilot sat watching the dials of experience and pulling the levers of action. We were, neuropsychologically speaking, all over the place. And anyway, who did we think was pulling the levers in the little soul-pilot’s head? If we found a ghost in the machine we’d have to start looking for the machine in the ghost.

Belief in an inner essence, or central core, of personhood, was called “ego theory”. The alternative, “bundle theory”, made more neurological sense but offended our deepest intuitions. Too bad, I thought. We should learn to face facts. The philosopher Derek Parfit put it starkly: we are not what we believe ourselves to be. Actions and experiences are interconnected but ownerless. A human life consists of a long series - or bundle - of enmeshed mental states rolling like tumbleweed down the days and years, but with no one (no thing) at the centre. An embodied brain acts, thinks, has certain experiences, and that’s all. There is no deeper fact about being a person. The enchanted loom of the brain does not require a weaver.

Parfit devised a famous thought experiment. Imagine being teleported. A special scanner records the state of every cell in your brain and body and digitally encodes the information for radio transmission. Your body is destroyed in the process but reconstructed as soon as the signals are received and decoded at your destination. You “arrive” in precisely the same condition that you “left”, identical in body, brain and patterns of mental activity. Your memories, beliefs, plans, skills and emotions are perfectly intact and you go about your business feeling and believing that nothing about you has changed in the slightest. It’s just like waking from a dreamless sleep and getting on with the day…

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