The Mind-Body Problem

We all have minds. But what is a mind?

Is it completely different from the body which is a physical system?

Or is it just a part of this physical system, that is, is it just a mode of our brain’s functioning?

Mental states: believing, wishing, dreaming, etc.

Physical states: states of our bodily system e.g. our actions, appearances, processes occurred in internal organs etc.

Differences between the two states:

Only physical states can be publicly observed either directly or indirectly.

Mental states are privately accessed only, but not by the five senses (seeing, hearing, touching, tasting, smelling). We can only be conscious of our mental states.

The common sense view: mental states are completely different from physical states; they are non-physical or immaterial. Therefore, they must be produced by an immaterial entity i.e. the soul.

Therefore, human beings are composed of two distinct elements: the physical (body) and the mental (soul).

Socrates’ definition of death:

“Is it simply the release of the soul from the body? Is death nothing more or less than this, the separate condition of the body by itself when it is released from the soul, and the separate condition by itself of the soul when released from the body? Is death anything else than this?”

Plato, Phaedo

Science: impact of brain research

Feelings, beliefs, hopes, intentions etc are located within the structure of the brain.

Mental states are brain states. (cf. water=H2O)

Therefore, human beings are part of the natural (physical) world.

http://www.euronews.com/2012/12/20/a-machine-which-can-read-your-mind/

If we consider both the common sense view and the scientific view as arguments, then both arguments are unsound.

The task of philosophy is to use logic to probe deeper by presenting stronger arguments for these two positions.

The mind-body problem restated.

Since we can be conscious only of mental states but not of the mind itself, the problem will be restated as: are mental states physical states? i.e. are mental states identical with brain states?

Descartes’ Project

René Descartes tackles questions no.2, 3 and 4 as a system taking question no.4 as the basis.

Skepticism

We cannot have knowledge because:

1.Knowledge must be certain.

2.Nothing is certain since everything can be doubted

Two senses of doubt:

Ordinary sense: we doubt that a statement is true because there’s no adequate evidence for it.

Philosophical sense: we doubt that a statement is true because there’s no conclusive evidence for it.

To have the conclusive evidence that the statement X is true, it must be inconceivable that X is false.

For X to be conceivably false, we must be able to think of a possibility in which X is false.

Descartes: If a statement can be doubted, then it is false.

Skeptic: If a statement can be doubted, then we don’t know whether it is true or false.

Descartes’ position is stronger than that of the skeptic. Why does Descartes want to make it that way?

How to refute a theory.1. Present the theory in its strongest form2. Use an argument to show that it is wrong or unreasonable

If this is successful, then the theory in its weaker forms will also be refuted.

Our senses sometimes deceive us, therefore our senses are unreliable.

Thus any statements derived from the senses can be doubted.

Therefore any statements derived from the senses are false.

Any experiences we have while we are awake can also be our experiences in our dreams. That is to say the two sets of experiences have the same characteristics.

Therefore if what we experience in our dreams is false then what we experience while we are awake is also false.

Dualism

Physicalism

Even though Descartes’ argument is invalid, his thought experiment highlights the formidable obstacle to the physicalist’s project.

Arguing along Descartes’ line, I can prove that I exist but I cannot prove that other people exist, nor that their minds exist. This is because the following statement is false: I can doubt that their bodies exist but I cannot doubt that they exist.

That means a person’s consciousness is closed to the public and thus closed to science. When a person is sad, science can use an instrument to detect brain signals that can be correlated with sadness. But that instrument cannot feel that person’s sadness.

This does not imply that the mind is distinct from the body; but it poses a problem for the physicalists. For physicalism to be credible, it must be able to explain consciousness in physical terms.

A challenge to dualism

The soul is said to leave the body. Then in order to exclude any similarity to the body, any sort of idea that some gaseous thing is meant, the soul is said to be incorporeal, non-spatial; but with that word ‘leave’ one has already said it all. Show me how to use the word ‘spiritual’ and I shall see whether the soul is non-corporeal and what you understand by ‘spirit’.

Ludwig WittgensteinZettel