What are the three main views in the mind-brain problem?

The mind-brain problem is the issue of how the mind is related to the brain.
Three main views on this problem are:

  • Dualism
    The mind (or soul) is something independent of the body
  • Materialism
    The mind is nothing but a by-product of the biological processes taking place in a particular brain.
  • Functionalism
    The mind is indeed realised in a brain, but it could be copied in any other brain.
    Just like information on a computer can be copied to other computers.
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The mind-brain problem, free will and consciousness - summary of chapter 7 of Historical and conceptual issues in psychology, by Brysbaert, M and Rastle, K (second edition)

The mind-brain problem, free will and consciousness - summary of chapter 7 of Historical and conceptual issues in psychology, by Brysbaert, M and Rastle, K (second edition)


Foundations of psychology
Chapter 7
The mind-brain problem, free will and consciousness


Throughout history, humans have been impressed by their ability to reflect about themselves and the world around them.
Self: the feeling of being an individual with private experiences, feelings and beliefs, who interacts in a coherent and purposeful way with the environment.

Mind-brain problem: issue of how the mind is related to the brain.
Three main views

  • Dualism
    The mind (or soul) is something independent of the body
  • Materialism
    The mind is nothing but a by-product of the biological processes taking place in a particular brain.
  • Functionalism
    The mind is indeed realised in a brain, but it could be copied in any other brain.
    Just like information on a computer can be copied to other computers

Dualism: the mind is independent of the brain

Mind: aggregate of faculties humans (and animals) have to perceive, feel, think, remember and want.
Dualism: view of the mind-body relation according to which the mind is immaterial and completely independent of the body; central within religions and also in Descartes’ philosophy.

Dualism in religion and traditional philosophy


Dualism is central to religions.
They are grounded in the belief that people possess a divine soul created by God, which temporarily lives in the body, and which leaves the corpse upon its death.
The soul is what gives people their purpose and values in life.
It usually aims for the good, but can be tempted and seduced by evil forces.
This gave rise to the demonologist view of psychopathology.
Demonologists view: the conviction that mental disorders are due to possession by bad spirits.

Plato and Descartes

Dualism was central in the philosophies of Plato and Descartes.

  • Plato maintained that the soul exists before, and survives the body.
    Human souls were leftovers of the soul of the cosmos and travelled between the cosmos and the human bodies they temporarily inhabited.
    • Human souls had knowledge of the realm of ideas
  • According to Descartes humans were composed of a divine soul in a sophisticated body
    The soul was immaterial and formed the thinking part of the person.

Cartesian dualism: theories in which the mind is seen as radically different from the body and as independent of the biological processes in the brain.

Dualism in philosophical writing does not focus to the mind’s fate after death.

Dualism in early psychology and lay thinking

Dualism in early psychology

In the second half of the nineteenth century a growing number of scientists began to question the dualistic view.

  • They felt uncomfortable with the emphasis religion placed on the immortality of the soul, the connection of the soul to a divine entity, and its independence of the body

They were unwilling to reduce the human mind to nothing but brain tissue.
The distinction between mind and body was attractive to early psychologists because it provided them with their own study area that could not be invaded and taken over by brain scientists.

Dualism in lay thinking

Dualism nowadays still is the fundamental attitude people have about the relationship between the mind and the brain.

Dualism puts consciousness at the centre of human functioning and seems to give humans free will

Dualism has an intuitive appeal because it puts conscious information processing at the centre of our functioning and it gives us the feeling of being in control of our actions.

In dualist models consciousness is the core of human existence

Dualism in general gives priority to the mind.
Our conscious, deliberate thinking is at the centre of our existence and controls our actions.
Consciousness: word referring to the private, first-person experiences an individual lives through; contains all the mental states a person is aware of; part of the mind that can be examined with introspection.
Dualism puts consciousness at the centre of the person, because the mind (or soul) is the acting unit and the mind coincides with consciousness.
The actions of an individual are guided by the private, first-person experience of that individual.

Dualism and free will

Because in the dualist view consciousness is the centre of the mind, nothing happens unless it is licensed by the mind.
Free will: situation in which individuals can choose their course of action; choice is the outcome of an informed deliberation.
Three conditions must be met before an action can be described to free will:

  • The agent must have been able to do otherwise. Free will only exists when there is a choice
  • The act must originate in the agent, not in some external force
  • The act must be the outcome of rational deliberation
    • Acts that are erratic and unpredictable are not seen as free

Problems with dualism

Although dualism strongly agrees with human intuitions, it has come under severe attack since the second half of the nineteenth century, to such an extent that it is no longer a viable approach within the philosophy of mind.

The interaction problem

How to explain the mechanisms by which an independent mind (or soul) can influence the body.
Similarly, how can a non-physical, spiritual mind control physical brain processes?

The existence of unconscious control processes

The discovery that many mental functions seemed to happen outside consciousness.
John Locke was the first to give rise to this issue.

  • He wondered what happened to the mind when humans were asleep.
    If consciousness was the defining feature of human existence (as claimed by Descartes), did this imply that the human existence was interrupted during sleep?

Leibniz (1646-1716)
Thought that the human mind could not be limited to conscious thinking.

  • There is in us an infinity of perceptions of which we are unaware because the impressions are either too minute and too numerous, or else too unvarying, so that they are not sufficiently distinctive on their own.

He compared the universe to a living organism.
The building blocks were not material particles, but energy-laden and soul-invested units, which he called monads.
Four types of monads

  • Simple monads
    The bodies of all matter (organic and inorganic)
    Some type of unconscious and unorganized perception. They ware motivated by a tendency to keep in line with the existing, pre-established harmony of the universe.
  • Sentient monads
    Present in all living organisms, but not in inorganic material
    Had capacities for feeling pleasure and pain, and for the voluntary focusing of attention.
    Lacked the ability to reason about their experiences.
  • Rational monads
    Corresponded to the conscious minds of humans
    Possessed the capacity of apperception, the faculty not only to perceive but also to reflect upon what is perceived.
    Apperception was not entirely based on empirical evidence, but also on innate truths.
    Innate knowledge demonstrated by perception
  • Supreme monad
    Controlled and motivated by all other monads
    Omniscient and omnipotent God of Christian religion

Human consciousness was not aware of the activity of the simple monads and, to a large extent, of the sentient monads.
Still, these monads could motivate human behaviour.

Kant also started to wonder how much wider human knowledge was than the part people were conscious of.
Kant thought of unconscious representations as dark representations.

Leibniz’s and Kant’s thoughts were music in the ears of the German Romanticists.
They saw evidence for the argument that rational thinking was but the tip of human potential and the most interesting part of the mind was active below the level of consciousness.
They urged their readers to strive for unconscious artistic productivity and intuitive aesthetic sense.

The study of unconscious processing gained further momentum from the nineteenth-century neuropphysiologic discovery that reflexes and bodily functions were controlled by the spinal cord and subcortical structures, not by the cerebral hemispheres.

The disappearance of mystery forces in the scientific world

A reason why dualism lost its appeal was that it needed the existence of an immaterial, mysterious, animistic ‘soul’.
Two prime examples of mysterious ‘substances’ that had been postulated in science before but which in the end turned out to be materialistic phenomena that could be measured and manipulated

  • Phlogiston: substance that was believed to make materials flammable before the chemical processes of combustion were understood
  • Vital force: animistic substance thought to be present in living matter before the chemical and biological differences between living and non-living mater were understood

Given the mysteries of phlogiston and vital force in the end turned out to be chemical and biological processes that could be manipulated, an increasing number of scholars began to claim that something similar would happen to the mind.

Interim summary

  • The mind refers to a person’s faculties to perceive, feel, think, remember and want
  • In religions the mind is often equated with an immaterial, divine soul. This is an example of dualism. A similar view was defended by Descartes and, therefore, in philosophy is often called Cartesian dualism
  • Dualism is an intuitively attractive model of the mind-brain relationship because it gives humans free will and it readily accounts for the existence of consciousness in humans. The latter refers to the rich and coherent, private, first-person experience people have about themselves and the world around them.
  • Dualism does have problems explaining how an immaterial mind can influence the body, and how it is possible that so much information processing in humans occurs unconsciously. It also does not agree with a scientific world view, where there is no place for mysterious and animistic substances.

Materialism: the mind is the brain

The alternative: materialism

The idea of an independent, incorporeal mind (soul) as the core of a human being struck British empiricists in the eighteenth and the nineteenth centuries as quite implausible, although they had to be careful not to upset the church too much.
David Hume openly declared he saw no good reason why one should believe in a soul.

The idea of the mind as nothing other than a brain operation really took off towards the end of the nineteenth century.
Materialism: view about the relationship between the min and brain that considers the mind as the brain in operation.
Within psychology, the rise of materialism was one of the reasons why behaviourists wanted to get away from the study of ‘consciousness’.

The consequences for consciousness and free will

Materialism does not require consciousness or free will.

Consciousness is folk psychology

Paul Churchland (1981)
Consciousness as the centre of the human mind and the controller of human actions was not only an illusion but also a dangerous idea.
It gives individuals a misunderstanding of what makes them tick.
Consciousness and the associated opinions were examples of folk psychology.
Folk psychology: collection of beliefs lay people have about psychological functioning; no efforts made to verify them empirically or to check them for their internal coherence.

Is there still room for free will?

Rickard Dawkins (1979-2006)
The evolutionary theory was misunderstood in the first century after its introduction by Darwin.
The selection actually concerns the survival of DNA molecules.

  • The contribution of individuals to their offspring rapidly dilutes after a few generations, making it impossible that something ‘biological’ of an individual is preserved
  • Throughout history life forms have come and gone, to be replaced by others that were better adapted to the (changed) circumstances
    Species doe not survive either
    • The only things that have remained constant throughout are the genes that make up the living organisms
      They are the true survivors, and they have managed to mobilise a whole range of survival machines that keep them alive and enable them to multiply

In Dawkins’s view, humans are nothing more than survival machines for the genes that they carry around.

Problems with materialism

How can different experiences be compared?

Identity problem: the difficulty the materialistic theory of the mind-brain relationship has to explain how two events can be experienced as the same despite the fact that their realisation in the brain differs.
How is it possible for two humans to communicate if their brain codes differ?
Given the complexity and the flexibility of the human brain, it is next to impossible for two experiences of a particular input to be encoded in exactly the same way. How can the brain know these codes refer to the same stimulus?

How can we build a mind as the by-product of a brain?

Nobody has a convincing idea of how the human mind could be a by-product of the biological processes of the brain.

Interim summary

  • Materialism holds that there is no distinction between the mind and the brain, and that the mind is a direct consequence of the brain in operation. To make the distinction with functionalism clear, we take this to imply that the mind is linked to the specific brain in which it has been realised
  • According to the strongest versions of materialism, there is no consciousness or free will. Consciousness is an illusion, a form of folk psychology, and humans are comparable to robots or machines. According to Dawkins, they are the slaves of their genes
  • A fist problem with materialism was that it seemed unable to account for the identity problem: how can different exposures to the same event be experienced as the same if they are not encoded similarly? A second problem was that attempts to simulate the human mind as a by-product of biological or mechanical processes were not successful, whereas computers running sequences of instructions on stored information started to thrive

Operational computers: the new eye-opener leading to functionalism

Information transcends its medium

The efforts to make machines intelligent would confront researchers with the discovery that information can be thought of as a realm separate from the medium upon which it is realised.
Mathematicians and logicians in the nineteenth and twentieth centuries ventured that all intelligence could be represented by binary symbols upon which Boolean transformations operate.
Every medium capable of doing so could process the same information and was a Turing machine.

  • The Boolean approach could easily be applied to computers and was the fasted (only?) way to make machines intelligent
  • The building of operational, digital computers showed that information could transcend the medium upon which it was realised.

A solution to the identity problem

Because information in operational computers was independent of the precise ways in which it had been realised, the physical changes by which computers code zeros and ones worked with them did not really matter.
Similarly, the minute physiological changes that accompany a particular human experience may not be important, as long as they preserve the information code.
The same information can be realised and communicated in multiple ways.

Functionalism in philosophy

Functionalism: in philosophy, view about the relationship between the mind and brain that considers the mind as a separate layer of information implemented on a Turing machine; predicts that the mind can be copied onto another Turing machine.
Functionalists in philosophy from the 1970s onwards examined the functions of information, rather than the precise ways in which the information was realised.

Beam me up, Scotty

Thought experiment: hypothetical scenario that helps with the understanding of a philosophical argument.
What would teleportation do to the mind?

  • Descartes
    The mind does not come from biological brain processes and can not be teleported with the rest.
    Teleportation would result in the reinstatement of the body without the accompanying mind
  • Functionalist network
    Teleportation would work fine
    The mind is nothing but the information stored within the physiological network of the brain and, if the latter is restored, the mind should be back as well
    The mind will be transported as soon as the information code can be implemented on the new brain
  • Materialist
    The mind would survive the teleportation without any loss of information only when exactly the same brain is reinstated
    Because the mind depends on the specific brain operations that give rise to it, only a reinstatement of the original particles in their initial positions would result in a flawless transportation of the mind

Information as the saviour of free will?

Information allows humans to rebel against the genes

The fact that humans can encode, store, retrieve and manipulate information enables them to pursue intentions that need to coincide with those of the genes.

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