Free will,
Science is uncertain. God asks us to "chose this day who you will serve."
… When the first simple life forms appeared on Earth about 3.7 billion years ago, one of their most interesting essential qualities was that they did stuff. Before that, things happened: grains of sand tumbled around, chemicals reacted and volcanoes spewed out lava. But those were inert physical processes. The first life forms, however, used energy to work against the second law of thermodynamics – the principle that everything tends to become more disorganised over time – and hence stay alive. “Agency is a really core property of living things that we almost take for granted, it’s so basic,” says Mitchell.
It is here that we can find the source of our free will, he says. In fact, this is what the nervous system evolved for. “It is primarily a control system, the job of which is to define a repertoire of actions and choose between them. This control system has been elaborated over evolution to give greater and greater autonomy.”
For Mitchell, it is a mistake to think we can always reduce complex systems to their component parts and consider causation in nervous systems, say, at the level of their atoms. Contrary to this “reductionist” approach, complex systems like brains can only be understood by considering their interactions at higher levels of organisation.
This view has recently been put on a firmer footing by research that reconsiders the reductionist approach of seeking “microscale” causes. In 2022, Erik Hoel, then a neuroscientist at Tufts University in Massachusetts, analysed more than a dozen different kinds of causation in complex systems, proposed by researchers in fields from statistics to genetics and psychology. In every case, he found some form of “causal emergence” – where the causes of some phenomenon or behaviour emerge not at the microscale but a higher or more coarse-grained level of the system.
In the case of decision-making, then, a person’s thoughts and feelings and memories are as much genuine causal forces as what happens at the level of atoms and neurons. “The idea that every event has a cause is only a problem for free will if it’s taken to mean that every cause is at this lowest level, it’s all physics,” says Mitchell. “But the entire structure of a nervous system can be a cause of things – you can be a cause.” Which suggests we might just be the captains of our souls, after all.
Whether any of this will allow free will sceptics and believers to reach an accord is far from clear. The opposing sides can’t even agree on what it would take to provide clinching evidence either way. Sapolsky will believe in free will only if some aspect of human behaviour can be shown to be completely devoid of prior influences. “Here are the neurons that caused it to happen – show me that they would have done the exact same thing if all the surrounding neurons sculpted by the previous history of your life had been different,” he says.
Mitchell says that is setting the bar impossibly high. “What kind of a being would be behaving free from any prior causes? They wouldn’t have a reason for doing anything, because reasons are past causes – it would just be a random behaviour generator.” But he adds that it is difficult to conceive of anything that would convince him that his argument is wrong, because it isn’t a simple, testable hypothesis. “It’s hard to say there’s some particular experiment that could show we do or don’t have free will,” he says.
Roskies, for one, isn’t holding her breath. “There have been thousands of years of discussion about this issue,” she says. “If there were a simple answer, we would have figured it out by now.”
Free will: Can neuroscience reveal if your choices are yours to make?
Science is uncertain. God asks us to "chose this day who you will serve."
… When the first simple life forms appeared on Earth about 3.7 billion years ago, one of their most interesting essential qualities was that they did stuff. Before that, things happened: grains of sand tumbled around, chemicals reacted and volcanoes spewed out lava. But those were inert physical processes. The first life forms, however, used energy to work against the second law of thermodynamics – the principle that everything tends to become more disorganised over time – and hence stay alive. “Agency is a really core property of living things that we almost take for granted, it’s so basic,” says Mitchell.
It is here that we can find the source of our free will, he says. In fact, this is what the nervous system evolved for. “It is primarily a control system, the job of which is to define a repertoire of actions and choose between them. This control system has been elaborated over evolution to give greater and greater autonomy.”
For Mitchell, it is a mistake to think we can always reduce complex systems to their component parts and consider causation in nervous systems, say, at the level of their atoms. Contrary to this “reductionist” approach, complex systems like brains can only be understood by considering their interactions at higher levels of organisation.
This view has recently been put on a firmer footing by research that reconsiders the reductionist approach of seeking “microscale” causes. In 2022, Erik Hoel, then a neuroscientist at Tufts University in Massachusetts, analysed more than a dozen different kinds of causation in complex systems, proposed by researchers in fields from statistics to genetics and psychology. In every case, he found some form of “causal emergence” – where the causes of some phenomenon or behaviour emerge not at the microscale but a higher or more coarse-grained level of the system.
In the case of decision-making, then, a person’s thoughts and feelings and memories are as much genuine causal forces as what happens at the level of atoms and neurons. “The idea that every event has a cause is only a problem for free will if it’s taken to mean that every cause is at this lowest level, it’s all physics,” says Mitchell. “But the entire structure of a nervous system can be a cause of things – you can be a cause.” Which suggests we might just be the captains of our souls, after all.
Whether any of this will allow free will sceptics and believers to reach an accord is far from clear. The opposing sides can’t even agree on what it would take to provide clinching evidence either way. Sapolsky will believe in free will only if some aspect of human behaviour can be shown to be completely devoid of prior influences. “Here are the neurons that caused it to happen – show me that they would have done the exact same thing if all the surrounding neurons sculpted by the previous history of your life had been different,” he says.
Mitchell says that is setting the bar impossibly high. “What kind of a being would be behaving free from any prior causes? They wouldn’t have a reason for doing anything, because reasons are past causes – it would just be a random behaviour generator.” But he adds that it is difficult to conceive of anything that would convince him that his argument is wrong, because it isn’t a simple, testable hypothesis. “It’s hard to say there’s some particular experiment that could show we do or don’t have free will,” he says.
Roskies, for one, isn’t holding her breath. “There have been thousands of years of discussion about this issue,” she says. “If there were a simple answer, we would have figured it out by now.”
Free will: Can neuroscience reveal if your choices are yours to make?
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