Since virtually all philosophers and scientists now reject such ontological dualism, we have to wonder what's going on here. In this essay I will try to explain why dualism has such enduring appeal, why it continues to confound philosophers and scientists.
Popular culture effortlessly absorbs a philosophical or scientific explanation when it seems intuitive. For example, we use any number of expressions drawn from psychoanalysis—ego, neurosis, narcissistic, subconscious—in daily life without a second thought. Where an explanation is counterintuitive, popular culture simply ignores philosophers and scientists. A striking example of this is that I know plenty of people who still believe that you can catch a chill from being cold and wet; an idea rooted in the four humours theory of the 2nd Century physician, Galen, which relates the qualities cold/wet with the phlegm humour.
So there is still a mind-body problem and it is non-trivial because the majority still find mind-body dualism intuitively plausible despite several centuries of powerful counter-argument and evidence. Any account of the mind-body problem needs to deal with this or it isn't useful. And yet such aspects of the problem are not even part of the philosophy curriculum. Rather, they are dealt with by a completely different academic department, psychology, as though belief is no concern of philosophers. Moreover, philosophers dismiss non-believers as cranks, idiots, or dupes.
As a rule of thumb, I contend that when a problem has been discussed without any resolution for many centuries we have to consider that perhaps we have framed it badly.
Alternative Approaches to Standing Problems
When I took up the problem of identity as reflected in the traditional dilemma of the Ship of Theseus, I realised—with help from John Searle—that the traditional framing of the problem effectively made it insoluble. This may have been unconscious when the problem was first posed, but there's no excuse for retaining this unhelpful approach.
John Searle's On the Construction of Social Reality proposes a useful matrix for thinking about facts. On one axis is the objective-subjective distinction and on the other is the epistemic-ontological distinction. This gives us a grid of four different kinds of facts.
Ontologically objective facts concern the inherent features of an object that are independent of any observer. An example of this is: a screwdriver is made of metal and plastic or wood.
Epistemically objective facts concern statements that are true because we have prior knowledge. We know that the object is a screwdriver only if we have prior knowledge of modern building technology. But everyone who knows what a screwdriver is knows that this screwdriver is one.
Ontologically subjective facts concern statements that are true because of the observer's relationship with the object. Searle especially links this to functions. The function of a screwdriver is to turn screws. But unless you know what a screw is this doesn't make sense. Moreover the function is not inherent in the materials of the object. A function is something that humans impose on objects. The fact that a screwdriver is for turning screws is a real, but subjective fact.
Epistemically subjective facts exist only in the mind of the observer. For example, "this is my favorite screwdriver" is true for me, but you may have a different favourite screwdriver. And the difference does not invalidate either fact. There is no contradiction because the fact is relative to the individual.
With respect to the ship of Theseus, an ontologically objective fact is that the ship is made of timbers arranged in such a way that it floats and can move easily through the water. An epistemically objective fact is that this arrangement of timbers is called "a ship". An ontologically subjective fact is that the function of this ship is to ferry people across the ocean. And an epistemically subjective fact is that this ship belongs to Theseus, it is Theseus's ship.
Traditionally we are supposed to ask, "Is it the same ship when all the timbers have been replaced?" And this generally ties us in knots. Some wish to say it is the same ship because the whole is unchanged, while some wish to say it is not the same ship because all the parts have changed.
My approach is to look at the different types of facts. For example, the ship is a ship at the start of the process of change and it is a ship at the end of the process. We can identify it throughout as a ship. So it has identity qua ship in the mind of any observer who knows what a ship is. This fact is epistemically objective. The ship can carry out its function throughout, so it has identity qua function, i.e. being an ocean-going passenger boat. This fact is epistemically subjective.
The problem here is that the identity of the ship is subjective: it exists in the mind of the observer, not in the object. If the observer believes it to be Theseus's ship then, to them, it is. If I have a different belief that may also be true and the difference does not necessarily invalidate either belief. The ontological status of the ship doesn't matter. It could be, and probably is, purely hypothetical.
The ship qua ship or qua ferry very obviously has identity over time (though I don't see this approach in the account of the problem that I have read). But the kind of identity we are being asked about when the question is framed as—Is it the same ship?—is subjective, i.e. it's not inherent in or to any ship.
The least interesting and least answerable questions are the ones that philosophers typically ask without delineating what they mean by identity, i.e. Is identity vested in the whole or the parts? The answer is that identity is in the mind of the observer. It is a belief about the ships. And as we know, belief amounts to having an emotion about an idea. Opinions are post hoc rationalisations of such emotions. And this means that the order of production is
feeling → belief → actions →reasons
Not the other way around.
There are two points here. The first is that philosophers can't afford to ignore how people actually think and propose solutions in a social vacuum. They may technically right, but if everyone ignores them, what is the point?
The other point is that philosophers are often wrong. The further back in history that we go, the greater the likelihood that philosophers are trapped in an unhelpful way of thinking about an issue. We don't have to accept the traditional way that philosophical problems are framed, especially when centuries of argument have not led to any resolution. If we can see a better way to think about the problem then we are free to adopt it and give the finger to philosophers.
Why We Still have a Mind-Body Problem
Given the overwhelming consensus amongst academics and intellectuals for ontological monism, why do we still routinely encounter the mind-body problem? I've tried to argue that the mind-body problem would be better framed as the matter-spirit dichotomy. I think this is a more general statement of how people actually think about the mind-body problem. People tend to think of matter as cold, dull, hard, dense, lifeless; and by contrast spirit is warm, bright, immaterial, diaphanous, alive. The body is a thus a special case of matter, in this view, because it is matter animated by spirit. Life was seen as something added to matter: an élan vital, or spark of life (such a view is termed vitalism).
If you have ever seen a corpse you know that it is very different from a living body. With reference to a living body, the corpse has shifted decisively towards the archetype of matter. The life has gone out of the person. The difference is what we conceptualise as spirit. Across many cultures, the ancients understood spirit as synonymous with breath. Terms such as spirit, animus, prāṇa, qi氣, and so on all mean "breath". In the Christian tradition this is epitomised by Yahweh breathing (spiritus) life into the clay body he fashioned for Adam. Adam's soul is the breath of God.
For the longest time, death was equated with the cessation of breathing. And before resuscitation methods were invented this was adequate. Once we realised that forcing air into the lungs of the "dead" person could revive them, we needed new definition of death. Around the same time the function of the heart was discovered and the cessation of the heartbeat became the new definition. Then we learned how to restart hearts and discovered brain waves and the cessation of brainwave activity. Popularly, however, the cessation of breathing is still associated with death. Someone who has been resuscitated is said to have died and come back, and their experiences while their breath or heart stopped is erroneously termed a "near death experience" and treated as a source of knowledge about the afterlife. The fact that we continue to have such experiences is seen by some as proof that there is an afterlife.
Other types of experience can also be interpreted as the mind being independent of the body: lucid dreams, out-of-body experiences, dissociative experiences brought on by trauma, drugs, or physical injury (think of Jill Bolte-Taylor's stroke). And we don't need to have one of these ourselves to find accounts of them plausible. Bronkhorst (2020) deals with how accounts of such experiences are transmitted by those who have not experienced them and become part of the public discourse. I keep in mind also the quote from The Ego Tunnel by Thomas Metzinger:
For anyone who actually had [an out-of-body experience] it is almost impossible not to become an ontological dualist afterwards. In all their realism, cognitive clarity and general coherence, these phenomenal experiences almost inevitably lead the experiencing subject to conclude that conscious experience can, as a matter of fact, take place independently of the brain and body. (p.78. Emphasis added)
The urge to dualism is really quite strong. It is matter-spirit dualism that keeps alive the possibility of an afterlife and also a desire for an afterlife that helps keep dualism alive. This is not something humans are likely to give up on soon, even though for many intellectuals life after death is simply not possible.
Another problem that John Searle pointed out that was that materialism is still rooted in ontological dualism. Materialists still divide the world into two substances; the difference is that they assert that matter is real and mind is not real. Idealists do the same but assert that matter is unreal and mind is real. Even though a materialist may argue that mind is not real—that it is a mere epiphenomenon—they still tacitly concede a substantial difference between mind and matter. They still talk about two distinct substances, even if one is unreal. Lay people pick up on this kind of equivocation even if they can't put it into words.
This tells us that materialism is not an answer because it does not go far enough. If the thesis is idealism and the antithesis is materialism, then we need a synthesis of the two. One synthesis is genuine ontological monism which holds that there is no ontological distinction between mind and matter, that neither can be reduced to the other. In order to address the persistence of dualism we have to invoke epistemology.
Epistemic Pluralism
We can all observe that we have different inputs into our sensorium. I know the world of objects through sight, hearing, taste, smell, touch, temperature, kinaesthesia, etc. I know the world of mind through conscious mental activity and the appearance of pre-formed results of unconscious mental activity emerging into my awareness (intuitions, etc). In other words, even if we formally accept a monistic world in which mind and body are manifestations of a singular, unified reality, there is still an inescapable epistemic distinction between our knowledge of the world and our knowledge of mind.
It is this epistemic distinction that fuels the plausibility of the ontological distinction,especially in the light of out-of-body experiences and other altered states that give the vivid impression of mind independent of matter.
Most people, most of the time, suspend disbelief and proceed in daily life as naive realists. To do otherwise would be inefficient and potentially dangerous. Anyone can examine their experience and ponder the distinction between perception and reality. We all know that there is a difference because our perceptions lead us astray in minor ways quite often. For example, mistaking an object for a threatening agent (e.g. a predator or a dangerous defensive agent like a snake or spider), or getting a colour wrong because of the lighting or background. But note that I never make huge mistakes like perceiving my home to be in Cambridge, England, only to discover one day that in fact I still in Auckland, New Zealand. Glitches on this scale are a sign of pathology. Moreover, minor glitches tend to resolve themselves quite quickly; we may mistake a stick for a snake at a glance, but this does not survive sustained attention. We usually recognise that the "snake" is a stick.
Of course there are abnormal perceptions. Colour-blindness, for example. One can live with colour blindness without too much danger, but one cannot safely pilot an aeroplane. With psychotic delusions the problem becomes more serious. If I perceive my children as demons and follow the urging of internal voices to kill them, the result is catastrophic for everyone involved.
Normal perception is quite reliable and where it is unreliable it errs on the side of protecting us from danger or it is trivial. And so, in daily life, we take perception as reality and most of the time this is fine. Keep in mind that humanity evolved over millions of years and attained the anatomically modern form about 200,000 to 300,000 years ago. For most of this time we were all naive realists and ontological dualists and we survived and thrived. There appears to be no evolutionary disadvantage to being an ontological dualist. Arguably, it is possible that belief in an afterlife keeps us from despair over the fact that we all die and that ontological dualism gave believers some advantage.
The problem is that naive realism encourages us to reify experience, i.e. to consider that what we experience is reality without any intervening processes. And this means we have a tendency to reify the epistemic distinction between world and mind. Hence, so many of us find ontological dualism so plausible. However, this is just the default setting for human beings. It's not a conscious ideology. On the contrary it is only with sustained (and educated) effort that some of us are able to break away from the gravity well of naive realism and subsequent dualism and see the world anew.
Subjectivity
We know that our senses respond to a range of different stimuli from visible light, to physical vibrations, to temperature differences, to our own muscle tension. But all of these are turned into identical electrochemical pulses transmitted by nerve cells exchanging sodium and potassium ions across a semipermeable membrane, linked by synapses in which the signal is briefly carried by neurotransmitters. The point is that the signals that arrive in the brain are not distinguished by being of different kinds. They are only distinguished by where in the brain they arrive and the architecture of the brain. We are still arguing over the extent of the role of the brain in creating experience, but recently Lisa Feldman-Barrett noted that the optic nerves account for only about 10% of the inputs to the primary visual cortex. Fully 90% of the inputs are from elsewhere in the brain. Vision must involve a considerable amount of self-stimulation. And presumably the other senses must be similar. Moreover, we see similar patterns of brain activity whether the subject is seeing something or imagining it. Vision and visualisation both use the same parts of the brain. Which explains why hallucinations can be so compelling.
If we stop back from this level of detail and simply take perception as we perceived it then our "world" is made up from a variety of kinds of sensory stimulation: appearances, sounds, smells, tastes, tactiles, temperature differences, muscle tension, etc. And the characteristic of all of these is that they are objective to some extent. You and I may disagree on the pleasantness of an odour (epistemically subjective fact) but we agree that there is an odour. And this agreement leads us to conclude that the odour exists independently of either of us. The smell is an ontologically objective fact. If the smell is the reek of methyl or ethyl mercaptan (the sulphur analogues of methanol and ethanol) then we may agree that it serves the function of making natural gas for cooking detectable by its odour (epistemically objective fact).
The point is that for many of our senses there is some aspect of the information we have access to that is public and accessible to any observer, even if we disagree on some of the subjective facts. No one would ever argue that the pungent smell of ethyl mercaptan is not an odour. Even the synesthete is aware of perceiving one sensory modality in terms of another. Synaesthesia is not a delusion.
Again, our awareness of mental activity is not like our awareness of the other senses. We may be able to use functional MRI to see enhanced blood flow in different parts of the brain correlating with some experience, but the content of our mental activity is not available to anyone else. Our mental sense is ontologically and epistemically subjective. In some senses mental activity is analogous to digestion. We swallow food and it is digested within our body. The nutrients are absorbed by our gut and circulate in our blood. Those nutrients are not publically available, they are contained within us. We can detect changes in blood flow or blood components, but this information does not permit my nutrients to nourish your body.
In this view, subjectivity is not such a mystery. The brain is an internal organ, housed within the skull, and with the body as its interface with the world. Sense data comes in, muscles move in response to signals from the brain (and to some extent from spinal cord). It would make no more sense for mind to be public than it would for nutrition to be public. Inputs from the brain to the brain, i.e. from one part of the brain to another part of the brain are going to have a different flavour to those which come from outside the brain.
Conclusion
Despite advances in science and refinements in philosophy, we still routinely encounter the so-called mind-body problem. I've argued that this is so because there is a striking epistemic distinction in the sensory modes through which we experience mind and body, self and world, spirit and matter. We all have a tendency to reify this epistemic difference and treat it as a metaphysical difference. And this lends plausibility to the belief. We feel that self and world are quite different and thus we believe that they are, we take actions based on this belief, and we subsequently float reasons why we believe or why we acted in that way. This is the process:
feelings → beliefs → actions → reasons
Scientists and philosophers have decisively come down on the side of monism in their work, with a few holdouts that are not taken very seriously. The methods employed tell us that what seems intuitive and plausible is not the case. If we are interested in understanding the world as it is, then this is important.
Part of the problem is that many science communicators are still working with the classical theory of rationality: if you just present someone with the facts they will changed their minds. That is to say we start with reasons and expect people to work backwards, against the flow, and change how they act, believe, and feel. And it doesn't work. Sadly, right wing politicians have embraced this new model and now spend all their time trying to manipulate how we feel, while left wing politicians are still trying to make rational arguments.
On the other hand, there is no great disadvantage to being an ontological dualist. There appears to be no evolutionary disadvantage and there is no day to day disadvantage. When we combine the intuitive plausibility with the lack of any disadvantage for being wrong we get a persistent fallacy. Many of the dualists I know are simply not interested in metaphysical monism. To them it seems to lack salience, or if it is salient, then it is counterintuitive.
There is no getting around the fact that the audience for philosophy is human beings. If we ignore this and pursue truths in the abstract then we can easily become irrelevant to most people. Worse, many intellectuals fail to understand why their ideas don't take off and they blame the audience. As communicators, the responsibility lies on us to get our message across. We are making assertions and thus the burden of proof is on us. If we fail to get our message across, then we have to consider this our failure, not the failure of the audience. It is a poor teacher who blames the student.
As I write this, I am waiting to hear back from a conference organiser about a proposal to give a presentation. What I propose to do is tear down 2000 years of hermeneutics and exegesis and argue for an entirely new way of seeing things. I have outlined the reasons for doing this in ten peer-reviewed articles and dozens of essays here on my blog. At the same time as feeling confident in my conclusions, I am acutely aware that none of these articles has been cited. I think some of them have been read by some people, but as yet my work is either unknown, or not considered salient. Heart Sutra articles still appear that are completely unaware of my articles. How to go about dismantling a familiar, and to some extent cherished, paradigm? If I had four hours I might present something like coherent case. But the best case scenario is that I'll have one hour. At best I'll be able to gloss some of the main points. I doubt anyone who has not already read the relevant papers will even follow the argument let alone be persuaded by it. And yet I have to try.
This is the kind of dilemma that philosophers face all the time in getting across new ideas. New paradigms seldom emerge fully formed and they are almost always resisted by the old guard. Max Planck quipped, perhaps a little unfairly considering history, that his field progressed one funeral at a time. In other words as the old gurda died they made space for new ideas.
Bibliography
Bronkhorst, Johannes.2020. "The Religious Predisposition." Method and Theory in the Study of Religion 33(2) :1-41.
Metzinger, Thomas. (2009). The Ego Tunnel: The Science of the Mind and the Myth of the Self. Basic Books.
P
. Birmingham: Windhorse.