The Mind-Body Debate

Mind-Brain Debate What is the relationship between mind and brain?

We are in fact considering an extreme case of reductionism

Reducing man to the component parts of consciousness Neuropsychology Neurophysiology Biology Psychologists generally This involves:

Mind-Brain Debate There is general agreement that the mind (i.e. consciousness) is a property of human beingness. Without a brain, there can be no mind!

Mind-Brain Debate How can the two be related? The body (brain) has Weight, Shape, Density and Physical Existence in time and space But the mind has none of these!

Mind-Brain Debate The Question is: How can a non- physical entity (the mind) Influence and produce changes in something physical (Brain/Body)

Mind-Brain Debate Example: Consider the act of scratching your head In strictly scientific terms, this should not be possible. It is a purely subjective decision. It involves the philosophy of two different kinds of substance:- Non-physical mind and physical body

Mind-Brain Debate The event of scratching my head involves the idea of causation. From a materialistic viewpoint that should be impossible Descartes believed that in this case, mind influences body

Mind-Brain Debate Bit of a problem, eh? However, Science (including psychology) cannot accept philosophical dualism – it’s either one or the other, mind or body.

Mind-Brain Debate There is an evolutionary perspective – what survival value is there in consciousness/mind? No value – unless it can bring about changes in behaviour. Subjective experience says – mind does affect behaviour – try scratching your head!

Mind-Brain Debate We have evolved with minds. Biological evolution has been for survival value. If species doesn’t survive it doesn’t evolve. We can assume that mind and body have evolved together for some reason because we have survived!

Mind-Brain Debate Two main theories Dualism – mind and brain coexist Monism – mind and brain are separate

Dualism theories Descartes Epiphenomenology Interactionism Psychophysical Parallelism

Descartes Mind influences body through pineal gland But Descartes believed body could not influence mind. Descartes

Humphrey (1992) disagrees with Descartes. Philosophy of Pain

PAIN My pain can hardly count as a physical event. It is not part of the objective world. It is not physical

PAIN From the fact that there is no accompanying brain activity, we could say that my brain-based pain belongs nowhere else than in the world of physical material. It is, after all, nothing other than a physical event. So, my pain – that is, my experience of pain – depends wholly on brain activity.

PAIN Problem: to explain how and why and to what end the dependence on the non- physical mind and the physical brain has come about. Somehow, between neural transmission and experience, there is a conversion. It is nowhere near being understood.

Epiphenomenologists Mind influenced by brain – reverse to Descartes. An Epiphenomenon is ‘an accompanying event’, outside the chain of causation. Epiphenomenology

Epiphenomenologists Behaviour is caused by direct brain action and consciousness is a sort of indicator that it is happening. Yet the mind is not involved in the process. Where have we heard that before? Behaviourism – radical behaviourism in fact.

Interactionists They believe the mind-body influence is two-way A kind of Liberal Democrat of the Mind-Body philosophy Interactionism

Parallelists Believe that mind and body exist but separately. No effects between them. Sometimes called psychophysical parallelists Psychophysical Parallelism

Monist Theories Can be mentalist – towards the mind end of the spectrum, or materialist, towards the body end. mentalist materialist

Mentalism or Idealism Only mental phenomena involved Humanistic Psychology

Materialism Two types Periphalist Centralist

Materialism – Periphalist theories The mind is reduced to behaviour Watson claimed that thought was really reduced to subvocalisation – a delicate instrument could pick it up. Logical behaviourism: I think it will rain is translated into behaviour when you unroll your umbrella. The mind = behaviour + disposition to behave

Centralist Materialism Mental processes are identified with purely physical processes in the brain. This is the aim of Cognitive Neuroscience

Mind-Brain Identity Centralist materialism Takes the view that mental processes are purely physical processes. They are no more than chemical reactions/physical states in the brain Mental states are equated with mind states

Mind-brain identity Place (1956): Is Consciousness a Brain Process? Attempt to identify structures in the brain which correspond to mental states What about brain-dead?

Mind-Brain Identity Eliminative Materialism And this really is where cognitive neuroscience is taking over! Attempt to replace psychology with neurophysiology

Mind-Brain Identity Crick (1994) “You, your joys, your sorrows, your memories and your ambitions; your sense of personality and free will, are in fact no more than the behaviour of a vast amount of nerve cells and their associated molecules”