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Modern neuroscience is eroding the idea of free will
IN THE late 1990s a previously blameless American began collecting child pornography and propositioning children. On the day before he was due to be sentenced to prison for his crimes, he had his brain scanned. He had a tumour. When it had been removed, his paedophilic tendencies went away. When it started growing back, they returned. When the regrowth was removed, they vanished again. Who then was the child abuser?
His case dramatically illustrates the challenge that modern neuroscience is beginning to pose to the idea of free will. The instinct of the reasonable observer is that organic changes of this sort somehow absolve the sufferer of the responsibility that would accrue to a child abuser whose paedophilia was congenital. But why? The chances are that the latter tendency is just as traceable to brain mechanics as the former; it is merely that no one has yet looked. Scientists have looked at anger and violence, though, and discovered genetic variations, expressed as concentrations of a particular messenger molecule in the brain, that are both congenital and predisposing to a violent temper. Where is free will in this case?
ON SEPTEMBER 13th 1848 a navvy called Phineas Gage was helping to build a railway in Vermont. As gang foreman, he had the job of setting explosive charges to blast a path through the hills near a town called Cavendish. While he was tamping down one of the charges with an iron bar, it went off prematurely, driving the bar clean through his head.
Accidents on construction projects happen all the time. The reason that people remember Gage's is that he survived it. Or, rather, his body survived it. For the Gage that returned to work was not the Gage who had stuck the tamping rod into that explosive-filled hole. Before, he had been a sober, industrious individual, well respected and destined for success. Afterwards, he was a foul-mouthed drunkard, a drifter and a failure. His identity had been changed in a specific way by specific damage to a specific part of his brain.
Gage's accident was intriguing because it cast light on the question of dualism. This is the idea that although the mindthe selfinhabits the brain, it nevertheless has an existence of its own and thus should not be equated with the brain. The sudden change Gage underwent suggested that brain and mind are not independent. If the essence of individuality can be changed by a physical accident, it implies that the brain is a mechanism which generates the self, rather than merely an organ which houses it. This observation moves the question who am I? from the realm of philosophy into the realm of science.
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