Light on the Cartesian dichotomy – evolution & neuroscience
Posted by robertpriddy on January 24, 2010
My summary/part transcript of the discussion on the BBC entitled: Exchanges At The Frontier, Episode 3 – Patricia Churchland This is a MOST interesting exchange because of the light it throws on the so-called body-mind duality (or matter-mind or matter-soul schizma) and how evolution provides answers to dispel miasmas and reinforce the fact of ‘free will’ – as I see it – against all religious determinisms.
How did the human brain evolve to care for others? If brain science can explain the cause of someone’s actions can we morally blame them for what they have done?
In ‘Exchanges At The Frontier’ (17 Dec. 2009), A.C.Grayling spoke to the neurophilosopher Patricia Churchland about what we now know about the machinery of our minds and the implications for society.
Neuroscience is starting to tell us how human decisions are really made, beginning to explain what it is that gives us a sense of our self and is shining light on the nature and the limits of ‘free-will’.
To understand mind we must look at the brain.
What we experience is very different from what we see when we look at a brain or a piece of spinal cord. This causes skepticism about the unity of brain and mind. Until recently very few functions of the brain were understood. But…
Evolutionary biolog: We know the structure of human and animal brains is very similar. Many animals do very complex things. solve complex problems. But could this merely be caused by instinct? Why should a Cartesian ‘spook substance’ need to exist to explain complex functions, but only in human beings?
Old concepts change as science advances… the concept of memory. Since 1950s when memory was though of as one thing, we have learned that memory is very complex which fragment into many sub-types and sub-systems. Under physical lesions, many parts dissociate. Eg. one can, in memory loss, retain skills while losing recollection of events. Short-term memory can be lost while long-term memory increases etc. Memory is multi-dimensional.
One remarkable case illustrates the question. A 40yr old man with stable re-marriage – step daughter claims she had been molested. Police found pornography on his computer. He began to get very sever headaches. A scan found a significant frontal (hypocampus) tumour… which is where sexual activity is controlled. Tumour removed, interest in young girls stopped… marriage back to normal. Then a relapse— tumour had regrown as not all was removed, also removed with same result.
People can lose their capacity to suppress an impulse.
The prarie vole was an evolutionary mystery. How do animals develop self-care. Then how to get from self-care to care for others. With mammals 2 major changes – use of a simple peptide – if the wrong peptide is predominant, the animal will lose all care for offspring. A mammal can feel a localised pain (big toe) or a ‘generalised sense of awfulness’ (eg. distress caused by calls from young). Prarie vole males care for the young. Male montain voles do not, they don’t guard the nest. The answer is in the microstructure of the brain. (Very detailed brain analysis and study of blocked receptors which then make self-care possible etc.). This means an evolution in behaviour, which is efficient for the species and which functions can be extended.
The same peptides is much the same as in prarie voles. Instead of fixed action patterns, in the developed state of human brains, there is flexibility, executive functions… steering attention, maintaining a goal, (deferring gratification, tolerating pain for a greater aim etc.
Culture clearly plays a huge role. It probably began with the development of agriculture (ca 10,000 years ago). Institutions developed which could enforce the right kind of behaviour. A ban is more trustworthy that one person.
Consciousness and freedom of the self: Choice the outcome of earlier states of ourselves and the earlier states of the universe? Descartes though free will “created from nothing” a choice. However, choices do have antecedent desires, beliefs,,, Discoverable differences between voluntary and involuntary choices… and a profile of these is being developed by neuroscience.
The [current UK and often prevailing] justice system does not require that a choice is not motivated by any precedent events. Though it does recognize compulsion by others as reducing responsibility.
Quote: A.C. Grayling: “requires a clearer conception of “free will.” Its formal identifier is the “genuinely could have done otherwise” requirement: but not only does that itself require unpacking, we also need to look for the fMRI (functional Magnetic Resonance Imaging) traces that suggest which structures in the brain import novelty into the world’s causal chains, making their possessor a true agent, and not merely a patient—a sufferer—of the universe’s history.”
Comment:If self-care arises only when a particular peptide is dominant, then the vast history of evolution gives room for countless such changes which result in what were once thought to be the human ‘instincts’ of motherhood, spontaneous compassion and all those observable human reactions which underpin what we now call ‘human values’. There is absolutely no need to posit an Invisible Being – found nowhere – which could instruct humanity morally… nature has done it through evolution. Of course, those who are psychologically or otherwise personally dependent on belief in a God will say that He (She or It) created nature may try to argue that God created evolution! This is the final crunch… the last argument which can never be validated in any way whatever. Some people believe what they want despite anything… there is probably no saving many of them.