I. Definition

Dualism can refer to any philosophy that believes in two. But two of what? There are countless forms of dualism in different philosophical traditions -far too many to cover in one article! So in this article, we’ll cover “mind-body” dualism, which is by far the most important form of dualism in modern European/American philosophy. It should not be confused with “Manicheanism,” which is a completely different idea that sometimes takes this name!

In the modern world “dualism” most often refers to “mind-body dualism,” or the idea that the mind is separate from the body. That is, a dualist is someone who believes that knowledge, thought, consciousness, the self, etc., exist in some way beyond the physical body. Opponents of dualism are called monists, and they believe that the mind is part of the body — that consciousness is produced entirely by the central nervous system, and that the self exists entirely in the material world.

Dualism opens up a lot of philosophical and spiritual possibilities that would be otherwise closed. For example, physical objects aren’t permanent, but can be destroyed — if dualism is true, then it’s possible that our minds can last forever. In general, dualism is associated with belief in a transcendental soul, whereas monism is associated with the absence of a transcendental soul (see Transcendence and Materialism). Nonetheless, many influential philosophers reject dualism because it is unscientific, or because its logical structure is unpersuasive to them.


II. Dualism vs. Monism

To understand the difference between monism and dualism, it might help to focus on one particular aspect of the mind: consciousness, or the mind’s ability to examine its own processes in real time. Consciousness is arguably the most important aspect of the human mind — without it, would we even be human at all? Monists and dualists have opposite views on consciousness.

The mind is separate from the body. Consciousness is a state of mind that can’t be understood purely in terms of the body. In order to understand consciousness, we have to examine abstract logic and/or use faith — studying the brain is not enough.The mind is part of the body. Consciousness can be understood as a function of the human brain, and therefore the best way to understand it is to study the brain.

Among modern philosophers, monism is generally more popular than dualism. However, dualism has been more popular historically, and the logical problems here are far from settled — it remains to be seen whether dualism can make a comeback.


III. Quotes About Dualism

Quote 1

“You don’t have a soul. You are a soul. You have a body.”

No one’s entirely sure who first said this, but it’s often attributed to C.S. Lewis, author of The Chronicles of Narnia. It’s about dualism because it distinguishes between the body and the soul, whereas a monist would say that these are two sides of the same coin (or, they might simply deny that the soul exists.) A monist would be more likely to say “your soul, if you have one, is part of your body.”

Quote 2

“A little breath, a little flesh, and Reason to rule it all — that is myself.” (Marcus Aurelius)

This comes from the writing of the Roman Emperor Marcus Aurelius (played by Richard Harris in the movie Gladiator). People debate sometimes whether Marcus Aurelius was a monist or a dualist — or some other category altogether! In this quotation, he sounds like a dualist, because he’s suggesting that Reason is something separate from his “breath and flesh.” However, Marcus Aurelius has other quotations in which he sounds more like a monist, or like he’s rejecting the whole monist-dualist controversy altogether!


IV. The History and Importance of Dualism

No one knows when human beings first started to believe in an “immaterial soul,” or in the difference between body and soul — so it’s impossible to trace the historical origins of mind-body dualism. However, paleoanthropologists (people who study human evolution) have discovered that our prehistoric cousins the Neanderthals used to bury their dead just like we do today. Is it possible that the Neanderthals believed in a soul and an afterlife, and that their funeral rituals were designed to give some peace to the departed’s soul? Of course, all we can do is speculate, but this is certainly a possibility.

In the western tradition, the question of mind-body dualism was first raised by Plato. For Plato, everything in the material world was a shadow of the Forms, which floated above the world on a more spiritual or “ideal” level (see Idealism). The body was stuck in the material world, but the mind could break free and explore the ideal realm at will, just by contemplating philosophical ideas. Plato believed in an immortal soul that would be released from the physical world after the body’s death.

It’s easy to see how this idea might have influenced religion: early Christians were heavily influenced by Plato, as were the early Muslims. They found that his idea of the Forms resonated with their concept of a spiritual divinity. It also gave them philosophical backing for their belief in the immortal soul.

The conversation changed dramatically when Rene Descartes stepped onto the scene in the 17th century. Through a complex series of arguments, Descartes reached the conclusion that consciousness could not be explained through monism. This was a revolutionary moment in philosophy, since earlier philosophers had not been very interested in consciousness. Today, students tend to find that surprising, because the mystery of consciousness seems so exciting and important to us. But this interest in consciousness is largely due to Descartes’s influence.

In the last century or so, more and more philosophers have been defending monism, arguing that there is no “soul” outside the body, and that abilities like consciousness are produced entirely by the body. These philosophers use modern science to debunk many older ideas about the meaning of “the soul,” and have had great success in convincing others that some version of monism is more logically persuasive than dualism.


V. Dualism in Popular Culture

Example 1

“If we can store music on a compact disc, why can’t we store a man’s intelligence and personality on one?” (Portal 2)

This quote from the video game Portal 2 expresses a common idea in popular culture: that with sufficiently advanced technology, you could “code” an entire human brain into a computer hard drive (or even a CD). It’s a little bit hard to see, but this idea is probably impossible if dualism is true! That is, if the mind exists separate from the physical body, then how can a physical medium like a hard drive or a CD contain a mind?

Example 2

“Sauron has regained much of his former strength. He cannot yet take physical form, but his spirit has lost none of its potency.” (Saruman, Lord of the Rings)

In the world of Lord of the Rings, dualism seems to hold true. Throughout the first film, the Dark Lord Sauron is described as a spiritual being with no body — clearly, this means that the mind and the self can exist in a non-physical form, and therefore monism is wrong.


VI. Controversies

The main disadvantage of dualism is its metaphysical complexity. Monism has the advantage of putting forward only one basic substance for the world: matter. Dualism, on the other hand, must address both matter and mind. This added complexity makes the argument less logically appealing (see Occam’s Razor). In addition, science is increasingly able to explain things that used to be shrouded in mystery — like consciousness, memory, the emotions, etc. Since science can only investigate the physical world, its discoveries almost always come in to support monism.

However, the case for dualism is still strong in its own way! One of the strongest arguments for dualism is the argument from phenomenology (this roughly translates to “argument from direct perception.” It works like this:

  1. Physical states are equally observable by everyone (if there’s a physical event in my brain, any scientist with the right sort of scanner can observe it)
  2. Phenomena are not equally observable by everyone. That is, no one else can experience what I am experiencing right now. For example, an observer can tell that I am in pain, but no one knows what that pain feels like except me. Or, an observer can see that I’m looking at a blue object, but no one knows how I perceive the color blue.
  3. Therefore, phenomena are not physical states
  4. The mind includes phenomena
  5. Therefore, there’s more to the mind than physical states.
  6. Therefore, monism is wrong!

If you were a monist, how would you counter this argument? There are basically two ways to go:

  1. Make a pragmatic argument — you simply say, “OK, phenomena are different from mental states, but they don’t actually matter………Therefore, dualism is still true for all practical purposes.”
  1. Another line of argument would be to say that in fact phenomena are observable by everyone, contrary to statement #2. In this argument, you would have to suggest that technology can eventually reach a point where it’s possible to peer into other people’s minds and experience exactly what they experience.
  1. Finally, you could argue that dualism and monism are both wrong! You might, for example, argue that mind and matter are just two of the many dimensions of existence. This is the approach frequently taken in Buddhist and Hindu philosophies, which reject the narrow monism and dualism of the Western tradition.


In the Western tradition, dualism can be traced back to…





“Neurobiology is impressive, but it will never fully explain the mysteries of consciousness, because science can only make discoveries about the physical world, and consciousness exists beyond that world.” This sounds like an argument for…





One of the main arguments for dualism is what we’ve called the Argument from…





Some experts argue that the Neanderthals believed in some version of mind-body dualism. What is their evidence?





1 Comment

  1. Reply

    This is great…

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