This chapter deals with the mind-body problem.

The mind-body problem is central to the philosophy of mind, brain and behavior. The term mind refers to a range of processes and things such as thinking, perceiving, consciousness, experiencing emotions and forming and behaving according to intentions.

Today, most scientists and philosophers believe that the mind should try to be explained in terms of a series of natural, physical phenomena. This is the only way to ultimately understand these phenomena for what they are, how they exist and how they shape human behavior and life.

However, mental states and processes have a number of properties that make it difficult to understand them as natural phenomena that are part of the physical world. For example, they are highly subjective in nature, for example the taste of sugar or the feeling of itching. How can subjective qualities be part of an objective physical worldview?

What is substance dualism?

Substance dualism refers to the theory that humans consist of two parts, a material body and an immaterial soul. The soul is seen as the site of mental states and processes. It is assumed that the body and the soul can exist separately from each other. Substance means that something can exist independently. Substance dualists emphasize that there is a continuous interaction between the soul and the body.

This substance dualism was invented by Descartes and is a product of his search for the foundations of scientific knowledge. According to him, these foundations should consist of knowledge that cannot be doubted. People can gain such knowledge by simply questioning everything they think they know and eventually, hopefully, find something they can't doubt. Doubting Descartes was very radical, meaning that little of what people think they know can withstand it. For example, according to Descartes, it is possible that the only thing that exists is one's experience of the world, rather than that this world actually exists. According to him, there was one thing that could not be doubted and that is the doubting person. Someone has to exist in order to doubt, so if you doubt you exist. This is where Descarte's famous saying comes from: I think, therefore I am. Descartes 'I think therefore I am' - argument was not intended as proof for substance dualism, but can be regarded as proof.

There is a second feature of Cartian dualism that remains intact in many contemporary philosophical and scientific theories of mind. According to Descartes, the mind was the place of the thinking 'I' that is separated from the outside world. It is only indirectly connected to the outside world through the senses (input) and through behavior (output). Knowledge of the world is stored in the mind. Knowledge, according to Descartes, consists of 'ideas'. Thinking is the manipulation of ideas. True knowledge consists of ideas that correspond to how the world actually is.

When scientists and philosophers present themselves as anti-Cartesian, they mean that they reject the idea that human beings are made up of two parts and that they do not believe in an immaterial soul.

It is easy to combine the two ideas - the soul is immaterial (1) and the separation between the outer world and the inner mind (2) - but the first characteristic need not be true for the second characteristic to be true. Many scientists and philosophers who reject the existence of an immaterial soul believe that the mind is made up of brain processes that are only indirectly connected to the outside world through the senses and behavior.

Descartes based his dualism on the idea that material objects cannot think and according to him language is needed to be able to think. Looking at language and reasoning, it is easy to see that Descartes' reasons for accepting dualism are insufficient. Today, people are surrounded by computers that can produce and understand language, but this does not mean that computers use language in exactly the same way that humans do.

What is the difference between ontology and epistemology?

Ontology is the study of what actually is or exists. Epistemology is the study of what people know and how people can know it. This is an important difference in the dualism discussion. The difference between the mind and the body in terms of what can be doubted is an epistemological difference. It is then not about the mind and the body as they exist, but about the mind and the body as they are known. The idea that the mind and the body are two different entities is an ontological thesis. It is a difference that exists regardless of what one thinks or knows. The argument for substance dualism based on doubt fails, because it draws an ontological conclusion based on an epistemological difference.

At the end of the nineteenth century, in addition to the philosophical problems surrounding substance dualism, there were also methodological problems. The only way to examine an immaterial soul was to ask participants to "look within" and report their subjective experiences as accurately as possible. These reports can never be verified and falsified by others. This makes it almost impossible to obtain objective, valid scientific knowledge.

In response to these methodological problems, John Watson renamed psychology a science of behavior. He found the soul, the mind, the consciousness, etc, all unscientific. The success of his and Burrhus Skinner's behaviorism led to the mind being a scientific taboo in the early 1940s. Outside of science, people still talked and thought a lot about the mind. This seemed to produce a dilemma: whether the way people used psychological terminology in everyday life was a remnant of pre-scientific thinking or a substantial part of reality escaped scientific criticism. The first option is problematic, because human language is an integral part of everyday life and of society. The idea that all this is built on scientific quicksand is very unappealing. The second part is just as problematic, however, because it implies that the scientific worldview is basically incomplete.

What is the paramechanical hypothesis?

The paramechanical hypothesis is a hypothesis and refers to the idea that intelligent behavior is characterized by its specific causal origin. Intelligent behavior is behavior caused by the mind, such as swimming in a pool, while unintelligent behavior is purely a physical event, such as sneezing. Gillbert Ryle's goal is to attack the paramechanical hypothesis. He wants to show that the Cartesian conception of mind is nonsensical and that behavior is an integral part of our conception of mind. According to the paramechanical hypothesis, scientists must invoke the mind to causally explain a specific category of behavior. However, this hypothesis adds nothing to our understanding of the difference between intelligent and unintelligent behavior, because humans made this distinction well before the hypothesis was conceived.

According to Ryle, the mind is part of behavior and not a causal force behind behavior. Ryle argues that concepts such as 'thinking' and 'willing' do not refer to processes in an unobservable entity, but that these concepts are used to refer to specific tendencies to exhibit specific behavior in specific circumstances. Such specific behavioral tendencies are called 'dispositions'. Ryle's point of view has been called logical or philosophical behaviourism. Note the difference with psychological behaviorism. Psychological behaviorism examines behavior rather than the mind. Logical behaviorism defines the mind in terms of behavior.

What is Identity Theory?

Identity theory rejects the idea that the mind is located in an immaterial soul. This theory has its origins in experimental psychology. The psychologist Edwin Boring suggested that consciousness was best understood as a brain process. This theory was initially ignored because it was taboo to talk about consciousness. Ullin Place rediscovered Boring's theory. Place became convinced that identity theory was the best alternative to the scientific, indefensible position of substance dualism.

Place was mainly concerned with explaining what is meant when one talks about consciousness as a brain process. According to Place, identity theory is not intended to characterize consciousness. To say that consciousness is a brain process means that consciousness is formed by a brain process. One cannot therefore define consciousness as a brain process.

J. J. C. Smart added something to identity theory. He claimed that mentalistic language is subject neutral. Mentalistic language refers to the way people speak about themselves and others in terms of what they think, feel, want, etc. By topic neutral, Smart means that mentalistic language says nothing about the nature of the mind. Mentalistic language is neutral as to whether the nature of the soul is material or immaterial.

There are two forms of identity theory:

• The Type Identity Theory: According to this theory, every mental state of a specific type is identical to a brain state of a certain type. One problem here is that different kinds of brains seem to be able to realize the same kind of mental states. This is called multiple realization.
• The Token Identity Theory: According to this theory, every token of a mental state type is identical to a token of a brain state type. This theory thus recognizes the potential for multiple realization.

The main problem with identity theory, in both forms, is its lack of explanation. It's one thing to argue that science shows that extremely complex electrical activity in the brain is identical to thoughts, sensations, intentions, etc., but that doesn't explain why that is the case.

What is the idea behind functionalism?

The idea behind functionalism is that people should characterize mental states not in terms of what they are, but in terms of what they do. A mental state, according to functionalism, is characterized by how it is caused and what causes it.

Will computer programs ever think?

Some philosophers and scientists think that computer programs will one day be able to think. Some of them think that people should see the brain as a biological computer. Three concepts are important to understand the idea of ​​a thinking computer:

• Symbols: Symbols are physical forms that represent other things.
• Syntax: The syntactic properties of a symbol are the physical properties with which a symbol can be recognized.
• Semantics: Semantic properties of symbols are all properties related to their meaning.

In order for Artificial Intelligence (AI) to be truly intelligent, a number of things must first be accepted:

• Thinking should be seen as meaningful and logically connected thoughts.
• Such thoughts should be seen as sentences or a series of symbols in a system.

The basic idea behind computationalsim is this: A computer is a machine that performs calculations on strings and thereby produces other strings. These calculations are based purely on the syntactic properties of these symbols. It is possible to program computers in such a way that when people look at the semantic properties of these symbols, meaningful mindsets emerge.

What criteria did Churchland use to judge the credibility and quality of a theory?

Churchland applied the following three criteria to assess the credibility and quality of a theory and thereby decide whether a theory is outdated:

• A theory is better if it can explain more phenomena.
• A theory must have the power to be developed, to accommodate new insights and new data arising from further research.
• A theory must fit into the worldview made up of generally accepted scientific theories. It must be compatible with other scientific theories.

What is Mental Realism?

Mental realism is the idea that mental states exist as discrete entities in people's minds that cause people's behavior. Daniel Dennett's interpretivism assumes that the mind actually exists, but not in the same way as tables and chairs. It's real like political movements and the latest fashion are real.

It is important here to distinguish between personal and subpersonal level of description. At the personal level of description, states and qualities are attributed to the person as a whole, such as one's height. The subpersonal level of description is the level at which parts of people are described, for example someone's immune system can be described on a subpersonal level. According to Dennett, mental states belong on a personal level of description.