- Apr 1, 2010
- Basic Beliefs
I would suggest that Desmurget is not overstating his case. I would point out that he is describing his experiments on the human brain and their results.
He is not the only one. The evidence coming out of neuroscience supports everything that has been said: basically, that the brain is a modular system which acquires and processes information and generates output based on architecture, condition, inputs and memory, a failure in any of these elements disrupting or destroying consciousness.
Will has no say in the matter.
Mark Hallet is a specialist;
How Can There Be Voluntary Movement Without Free Will?
''Humans do not appear to be purely reflexive organisms, simple automatons. A vast array of different movements are generated in a variety of settings. Is there an alternative to free will? Movement, in the final analysis, comes only from muscle contraction.
Muscle contraction is under the complete control of the alpha motoneurons in the spinal cord. When the alpha motoneurons are active, there will be movement. Activity of the alpha motoneurons is a product of the different synaptic events on their dendrites and cell bodies. There is a complex summation of EPSPs and IPSPs, and when the threshold for an action potential is crossed, the cell fires.
There are a large number of important inputs, and one of the most important is from the corticospinal tract which conveys a large part of the cortical control. Such a situation likely holds also for the motor cortex and the cells of origin of the corticospinal tract. Their firing depends on their synaptic inputs. And, a similar situation must hold for all the principal regions giving input to the motor cortex.
For any cortical region, its activity will depend on its synaptic inputs. Some motor cortical inputs come via only a few synapses from sensory cortices, and such influences on motor output are clear. Some inputs will come from regions, such as the limbic areas, many synapses away from both primary sensory and motor cortices. At any one time, the activity of the motor cortex, and its commands to the spinal cord, will reflect virtually all the activity in the entire brain.
Is it necessary that there be anything else? This can be a complete description of the process of movement selection, and even if there is something more -- like free will -- it would have to operate through such neuronal mechanisms.
The view that there is no such thing as free will as an inner causal agent has been advocated by a number of philosophers, scientists, and neurologists including Ryle, Adrian, Skinner and Fisher.(Fisher 1993)''
One of the things missing in Hallet's narrative is the events external to the brain, you know, the ones providing the external inputs. A guy says, "Raise your hand". Then, back inside the brain, we hear what he said, and then we decide "What the heck, I'll raise my hand", and then we act upon that intention by actually raising our hand.
Another thing missing is where the decision making takes place. Mark says, "Movement, in the final analysis, comes only from muscle contraction." That may be sufficient to explain a twitch, but it does not explain me deliberately raising my hand.
Mark finally points out, "There are a large number of important inputs, and one of the most important is from the corticospinal tract which conveys a large part of the cortical control." If it is a deliberate act, then the origin of the signal has to come from neural mechanisms that actually decide if I want to bother to raise my hand or not. "Raise your hand" is not understood by the motor neurons. They cannot act directly upon that until it gets through auditory sensation, word interpretation, and deciding what to do about it.
Fortunately, the brain comes with the neural functionality required to choose what the organism will do, and then to initiate that intention through the motor neurons.
Where's the free will? Well, as long as the brain is functioning well, and no one is pointing a gun at it, then the brain is free to decide for itself what it will do. But if there's a guy with a gun, then these are additional sensory inputs that must be converted into useful information so that the neurons in the orbitofrontal cortex can decide what to tell the motoneurons to do.
Apparently, other neuroscientists have identified where the decision making takes place. That's where the will is formed. Whether it was formed in the absence of coercion and undue influence is how we decide whether the choice was freely made.
So when was all this decided?