Mind-Brain Debate • What is the relationship between mind and brain?
Mind-Brain Debate • We are in fact considering an extreme case of reductionism
Mind-Brain Debate This involves: Neuropsychology Psychologists generally Biology Neurophysiology Reducing man to the component parts of consciousness
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 DebateHow 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
Descartes Interactionism Psychophysical Parallelism Epiphenomenology Dualism theories
Descartes 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 coud 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.
Mind influenced by brain – reverse to Descartes. An Epiphenomenon is ‘an accompanying event’, outside the chain of causation. Epiphenomenology Epiphenomenologists
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.
Interactionism Interactionists • They believe the mind-body influence is two-way • A kind of Liberal Democrat of the Mind-Body philosophy
Psychophysical Parallelism Parallelists • Believe that mind and body exist but separately. • No effects between them. • Sometimes called psychophysical parallelists
Monist Theories • Can be mentalist – towards the mind end of the spectrum, or materialist, towards the body end. materialist mentalist
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”