Mind-Body Relationship: Dualism vs Monism

The mind and body problem concerns the extent to which the mind and the body are separate or the same thing.

The mind is about mental processes, thoughts, and consciousness. The body is about the physical aspects of the brain-neurons and how the brain is structured.

Is the mind part of the body, or the body part of the mind? If they are distinct, then how do they interact? And which of the two is in charge?

Many theories have been put forward to explain the relationship between what we call your mind (defined as the conscious thinking “you,” which experiences your thoughts) and your brain (i.e., part of your body).

What is Dualism?

Human beings are material objects. We have weight and solidity and consist of various solids, liquids, and gases. However, unlike other material objects (e.g., rocks), humans also can form judgments and reason about their existence. In short, we have “minds.”

Typically humans are characterized as having both a mind (nonphysical) and a body/brain (physical).  This is known as dualism.  Dualism is the view that the mind and body both exist as separate entities.

Descartes / Cartesian dualism argues that there is a two-way interaction between mental and physical substances.

Descartes argued that the mind interacts with the body at the pineal gland.

This form of dualism or duality proposes that the mind controls the body, but that the body can also influence the otherwise rational mind, such as when people act out of passion.

Most of the previous accounts of the relationship between mind and body had been uni-directional.

What is Monism?

There are two basic types of monism:


Materialism is the belief that nothing exists apart from the material world (i.e., physical matter like the brain); materialist psychologists generally agree that consciousness (the mind) is the function of the brain.

Mental processes can be identified with purely physical processes in the central nervous system, and human beings are just complicated physiological organisms, no more than that.


Phenomenalism (also called Subjective Idealism ) believes that physical objects and events are reducible to mental objects, properties, and events.

Ultimately, only mental objects (i.e., the mind) exist. Bishop Berkeley claimed that what we think of as our body is merely the perception of the mind. Before you reject this too rapidly, consider the results of a recent study.

Scientists asked three hemiplegics (i.e., loss of movement from one side of the body) stroke victims with damage to the right hemispheres of their brains about their abilities to move their arms.

All three claimed, despite evidence to the contrary in the mirror in front of them, that they could move their right and left hands equally well. Further, two of the three stroke victims claimed that an experimental stooge who faked paralysis (i.e., lack of movement) of his left arm was able to move his arm satisfactorily.

Psychology & the Mind-Body Debate

The different approaches to psychology take contrasting views of whether the mind and body are separate or related.  Thinking (having freedom of choice) is a mental event, yet it can cause behavior to occur (muscles move in response to a thought).  Thinking can therefore be said to make things happen, “mind moves matter.”

Behaviorists believe that psychology should only be concerned with “observable actions,” namely stimulus and response.  They believe that thought processes such as the mind cannot be studied scientifically and objectively and should therefore be ignored. Radical behaviorists believe that the mind does not even exist.

The biologists who argue that the mind does not exist because there is no physical structure called the mind also follow this approach. Biologists argue that the brain will ultimately be found to be the mind. The brain, with its structures, cells, and neural connections, will, with scientific research, eventually identify the mind.

Since both behaviorists and biologists believe that only one type of reality exists, those that we can see, feel and touch, their approach is known as monism. Monism is the belief that, ultimately, the mind and the brain are the same thing. The behaviorist and biological approaches believe in materialism and monism.

However, biologists and behaviorists cannot account for the phenomenon of hypnosis. Hilgard and Orne have studied this. They placed participants in a hypnotic trance and, through unconscious hypnotic suggestion, told the participants they would be touched with a “red hot” piece of metal when they were actually touched with a pencil.

The participants in a deep trance had a skin reaction (water blisters) just as if they had been touched with burning metal. This is an example of the mind controlling the body’s reaction. Similar results have been found in patients given hypnosis to control pain.

This contradicts the monism approach, as the body should not react to unconscious suggestions in this way. This study supports the idea of dualism, the view that the mind and body function separately.

In the same way, humanists like Carl Rogers would also dispute materialism monism.

They believe that subjective experiences are the only way to study human behavior. Humanists do not deny the real world exists rather they believe it is each person’s unique subjective approach to defining reality that is important.

In the area of mental illness, a Schizophrenic might not define their actions as ill; rather, they would believe they had insight into some occurrence that no one else had. This is why humanists believe the study of how each person views themselves is essential.

However, the problem of the relationship between consciousness and reality from a subjective view has problems. The paranoid schizophrenic who believes the postal service “are agents for the government and trying to kill him” is still mentally ill and needs treatment if they are not to be a danger to themselves or the public.

Recent research from cognitive psychologists has placed a new emphasis on this debate. They have taken the computer analogy of Artificial Intelligence and applied it to this debate. They argue that the brain can be compared to computer hardware that is “wired” or connected to the human body.

The mind is, therefore, like software, allowing a variety of different software programs: to run. This can account for the different reactions people have to the same stimulus. This idea ties in with cognitive mediational (thinking) processes. In computer analogies, we have a new version of dualism that allows us to incorporate modern terms such as computers and software instead of Descartes’s “I think therefore I am.”

Olivia Guy-Evans

BSc (Hons), Psychology, MSc, Psychology of Education

Associate Editor for Simply Psychology

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

Saul Mcleod, PhD

Educator, Researcher

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, Ph.D., is a qualified psychology teacher with over 18 years experience of working in further and higher education.