In this post, I will bring my exploration of the realm of the mind to a close.
What is the best explanation of the form and nature of our conscious experiences? In my last three posts, I have considered various features of our experience that, I believe, do not and cannot have any complete explanation in physical reality.
Given the nature of consciousness and conscious experiences, our ability to reason, and our awareness of the self, I think materialism is just as incomplete of a philosophy as idealism. Just as idealism fails to explain our experiences of the physical realm, materialism fails to explain how we can have experiences at all. The evidence overwhelmingly demonstrates that both the physical and the mental exist.
This leaves me with the philosophy of dualism. As I explained in an earlier post, there are two major forms of dualism: property dualism and substance dualism. And I think substance dualism is the more reasonable position of the two. Briefly, here are my reasons why:
- If there are two radically different kinds of properties, mental and physical, it makes sense for there to be two different kinds of entities that have those properties.
- Property dualism has mental experiences but no experiencers. In my view, it cannot account for the first-person perspective of our experience without becoming substance dualism in disguise.
- Substance dualism provides the most natural account of personal identity over time, while property dualism implies that the self-awareness I discussed in this post is illusory.
- Property dualism has no active causation and no agents. It implies that free will and rational thought are just illusions.
- Only substance dualism accords with certain other aspects of the worldview that I believe to be best explanation of all of reality.
To elaborate on these points further: first, property dualism already introduces a kind of dualism in the entities, and not just the properties, that exist. There are entities or systems with only physical properties, and entities or systems with both physical and mental properties.
However, most forms of property dualism only assign mental properties to certain complex systems – but there is no strictly physical principle which can single out just which systems these are. The systems themselves effectively become new entities, bearing properties that are not derived from the physical properties of the matter making up the systems.
This seems to me to be nearly the same as a form of substance dualism that has mental entities bearing the mental properties, and standing in an embodiment relation with the complex physical systems. In fact, I think substance dualism is a simpler and more straightforward way of framing the way mental phenomena are related to the physical realm.
To evade this objection, property dualism would have to postulate something like “atoms of qualia” that could be associated with less complex physical subsystems, and that somehow combine to build up the mental phenomena that we experience. But I do not see any way this could work.
Second, property dualism is usually joined to a position called epiphenomenalism, which is that the mental properties of a system are only “along for the ride” and do not affect the system’s physical behaviour. Property dualism is generally thought to imply epiphenomenalism because the only entities that exist are physical, and physical entities are subject only to the passive causation described by the laws of physics.
Now, there could be new causal powers and liabilities among the mental properties that are acquired by certain complex physical systems. But I do not think the forms of mental causation that are available to property dualism could be active causation: active causation is essentially performed by a first-person perspective, and that leads us back to property dualism’s problem with incorporating first-person perspectives.
So mental causation would still just be passive, subject to natural laws operating in the mental realm. There simply is no such entity, in property dualism, that is capable of acting of its own accord and for its own reasons. This makes free will and rational deliberation into an illusion, which I think is a fatal flaw for any philosophical position. Property dualism, if true, would eliminate the existence of rational thought – and that makes it a self-defeating belief.
Third, substance dualism is implied by another aspect of what I believe to be the most coherent and comprehensive worldview. Specifically, substance dualism is implied by the existence of God and Christian doctrines about the afterlife.
I will be exploring why I believe what I believe about God and Christianity in future posts. Suffice to say that because of the implications of God’s existence, whatever independent reasons I have for believing in God are also reasons for believing in substance dualism.
So for the reasons I have given above, and in the last few posts, I believe that reality contains mental entities in addition to physical entities: the mental realm is as real as the physical realm. In particular, the self that I am aware of through introspection is an immaterial entity: a mental substance. (Recall that this is the philosophical meaning of substance, not implying that the self is made of any kind of material-like stuff.)
Since my self is immaterial and non-physical, but it is a real entity, we have to call it something. So we may call this self a mind, or a spirit, or a soul. Since it is a conscious first-person perspective with the capacity to be self-aware, to reason, and to exercise free will, we may call my self a person.
(As an aside, I believe the correct definition of a person is along these lines: a person is a member of a natural kind, the normal members of which have the capacities for consciousness, self-awareness, rationality, free will, and moral accountability. This is because my intuitions say that, for example, human beings who are in permanent comas, or who have been mentally disabled since birth, are still persons with intrinsic value even if they do not exhibit the capacities that we usually associate with personhood.)
My intuitions about my self lead me to believe that minds (or spirits, or souls) are metaphysically simple entities: they do not have separable parts. My self cannot be divided up into different pieces capable of independent existence. Though we can divide minds conceptually (for example, considering emotions as distinct from the faculty of the will), they cannot be divided up in reality. The “part” of my mind that feels emotions and the “part” that makes decisions cannot be ripped apart into distinct entities.
Minds, according to my view, are mental atoms (in the original sense of the word “atom,” before we learned that physical atoms could in fact be divided). Though they have highly complex properties (such as thoughts about abstract mathematics), they are not composed of more simple entities. This is one of the things that makes the mental realm so different from the physical realm.
Finally, though they are distinct, non-physical entities, the minds we are most familiar with (our own) are intimately related to certain physical systems, namely, our bodies. We are embodied minds. (In fact, it may be more accurate to characterize ourselves as body-mind composites.) So my position is a form of interactionist substance dualism. The body can causally affect the mind, and the mind can causally affect the body.
We experience both of these directions of causation all the time. My mind is constantly receiving sensations from my body, and I exert my free will to use my body to perform various actions throughout the day. Of course, through science we have discovered that this interaction is mediated via the brain – and our minds and brains are so intimately related that our physical brain states significantly impact our mental states.
This is not really an astonishing revelation of modern science. People have known for millennia that there are things we can do to our bodies (drinking certain fermented beverages, for example) that may alter how our minds function. Modern science has just shown us how this can be done in more detail, and perhaps that this can be done to a greater extent than we once imagined.
But my arguments in the last three posts point to the fact that, despite their close connection, our mental states are not the same thing as our brain states. Influence is not identity; our mental states are influenced by our brain states, but their essential features show they are not identical to our brain states.
So what are we to make of the mind’s dependence on the brain? My view is something like this: the immaterial mind uses the brain as an instrument of thought. The mind uses the brain to think, experience, and act within the world, in the same way that a pianist uses a piano to play music. This is the view that, to me, makes the most sense of what we know about reality.
Why our minds and bodies are so connected, and how they got that way, are deep and important questions – but they are questions for another time.
Objections to Substance Dualism
Now that I have articulated my position of substance dualism, I will consider the reasons weighing against it.
The first argument against dualism is the interaction problem. How can these two vastly different realms of reality, the physical and the mental, interact with each other as the dualist says? The objection is that the dualist posits an inexplicable causal interaction relationship between mind and body.
This objection presupposes that it is unreasonable to believe that something causes an effect if we cannot explain how that thing causes the effect. But this is just false, so the objection fails. You do not need to know anything about the physiological mechanisms of intoxication to reasonably believe that drinking alcohol will get you drunk. Likewise, our experience provides sufficient justification for belief in the causal interaction between the mind and the body. An explanatory mechanism for the causal interaction is unnecessary – though of course, it would be an advance in understanding.
Fortunately then, it is also false that the causal interaction between mind and body is totally inexplicable. Here is a plausible explanation: it is just among the basic causal powers and liabilities of the immaterial mind to be able to affect the brain in certain ways, and to be affected by the brain in certain ways.
The postulation of basic causal powers is a reasonable and natural move, given that the mind is a basic indivisible entity with other complex properties. Without a similar move, physicists could never explain how fundamental particles and fields interact with each other, for example. Under this view, the mind and the brain just interact directly with no intervening mechanism. And the fact that the mind and brain are so different does not really seem to be relevant to this.
A related objection is that the mind and body cannot interact, because such interaction would violate the laws of physics, and these kind of violations have never been observed. But I think this objection misunderstands what the laws of physics are.
The laws of physics are descriptions of the causal relationships within a physical system. They say what will happen within a physical system, absent any external influences that have not been accounted for. But a mental cause is just such an influence, especially since the laws of physics have been formulated based on experiments outside of the complex environment of human brains. The claim that the laws of physics are totally inviolable, even by non-physical causes, is simply unjustified.
In any case, is there any reason to suspect that such violations due to mental activity would be detectable? The mind could interact with the body by means of extremely small effects, which then propagate up to the observable level according to the usual physical laws. Plausibly, the brain is a chaotic system in the mathematical sense, so that very small differences in initial conditions can lead to very large differences in outcomes. Only the initial tiny input would be against the laws of physics, and it seems unlikely that we could measure such a thing in the environment of a living brain.
The opponent of dualism might complain that this makes dualism into an unfalsifiable hypothesis. That would be a valid complaint if dualism were a scientific hypothesis. But that is not, strictly speaking, what it is. Dualism is a philosophical position motivated by our first-person experience. So this complaint only has force if you believe that science is the only valid source of knowledge – which is just a belief that is unjustified and self-refuting.
Problem of Other Minds
The second objection consists of two related arguments called the problem of other minds and the problem of many minds. These problems ask, how do we know that the other people we interact with have minds? And how do we know that they only have one each? If consciousness is only first-person accessible, how do we know that anyone else has it?
This, of course, is still a problem for the opponent of dualism, but it is supposedly more of a problem for the dualist, because substance dualism posits entities (minds) that can only be known through introspection. So the belief in other minds is apparently only justified by the weakest possible inductive inference: a sample of one (your own mind).
Of course, this objection is easily overcome. Because the belief that other people have minds, and only one each, is most plausibly seen not as an inductive inference, but an abductive inference: an inference to the best explanation. And the best explanation of the behaviour that we observe from others is that everyone has a mind just as we find ourselves to have.
This is on top of the fact that the belief in other minds could easily be taken as a properly basic belief: a belief naturally formed in the context of our interpersonal experience, and therefore possessing inherent justification. So without evidence that other people do not have minds, it is reasonable to believe they do.
(As an aside, this response means we can also infer that, most likely, many kinds of animals also have conscious experiences and minds. However, since there is less similarity between ourselves and animals than there is between ourselves and other humans, the inference is not as strong. So animals likely have different kinds of minds than we do, if they have them. Specifically, there is no conclusive evidence that animals have the rational and volitional capacities that we do, so while they may have minds, it would be a stretch to assume that they are persons.)
A third objection that I have seen is that substance dualism is just too strange. What are these mysterious immaterial entities and subjective phenomena? They are just too far removed from our experience to be believable!
Obviously, this is a pretty weak objection. The mind is only strange and mysterious if you assume that physical reality is all there is, or that all reality has to resemble physical reality. Without that assumption, the mind is not strange at all. Really, there is nothing we are more familiar with than the mind. We just spend more time looking outwards, at the things around us, than we do looking inwards, examining the mind itself.
The fourth argument that I have found against substance dualism is Occam’s razor. This is the principle stating that, when we are formulating hypotheses in an inference to the best explanation, we should not postulate anything more than necessary to explain the evidence. So according to the objection, dualism is less preferable because it postulates two kinds of entities, physical and mental, while materialism only postulates one.
However, this objection only works if materialism and dualism have the same explanatory power. But my whole argument in the last few posts has been that this is not the case: the existence of the mental realm is necessary to explain our subjective experience; the physical realm is insufficient. So Occam’s razor does not cut against dualism.
Here is another way to put this. A materialist might say something to the effect that dualists need (and lack) substantial justification to postulate consciousness as a fundamental constituent of reality in addition to the physical properties of mass, charge, and spacetime. But that objection misconstrues the problem, because consciousness is not something postulated to explain the phenomena we experience. Rather, it is one of the phenomena that needs to be explained.
This brings us to the fifth and final objection against dualism, the argument from science.
Some people might claim that biology and neuroscience show that consciousness can be explained without the hypothesis of an immaterial mind. But I think an honest look at what we know shows that this is not the case.
We know much about the processes going on inside the brain, and there is absolutely no explanation for how those processes might give rise to first-person subjective experience. In fact, it is worse than that. There is absolutely no explanation for how any conceivable physical process might give rise to first-person subjective experience, even in principle.
The argument from science is that, even in spite of this difficulty, we should continue to expect that science will be able to explain consciousness by a natural, physical mechanism. Science, the objector says, has been all about demystifying the universe, explaining everything by the laws of physics. Dualism goes against this program, threatening to undo the progress of science and spread a primitive, anti-scientific worldview.
This, I think, is really nothing more than an optimistic scientism.
Science has certainly been successful in explaining many natural phenomena, but it is not the only source of knowledge. And it is simply false that, as some materialists put it, everything we have investigated so far has turned out to have a natural explanation via the laws of physics. Consciousness itself is the foremost counterexample. (The origin of the universe and its fine-tuning for life are two other problems that have proven quite difficult in this regard, I might add.)
Mental phenomena differ in very significant ways from other natural phenomena that we observe. Their first-person perspective and their subjective experiential quality are fundamentally unlike any natural phenomena that has ever been explained by science. So an inductive inference or reasoning by analogy that says, “Science has explained these other things, so it will be able to explain consciousness too,” simply is not justified.
Because of the privileged first-person access of conscious experience, the most that biology and neuroscience will be able to show is that there are certain correlations between our mental states and the physical states of our brains. But this kind of correlation does not conflict with the position of substance dualism – far from it, if we believe that minds use brains as instruments to think.
Furthermore, the justification for substance dualism does not come from its ability to explain our physical brain states, but from its explanatory power in the realm of our subjective experience, and from direct introspective awareness. So scientific advances that increase our understanding of neurology do not affect the justification for dualism. To do so, the scientific theory would have to explain how and why we have conscious experience – but as I have argued, the physical realm has no mechanism that can do this.
In the end, the study of science is actually impossible if dualism is false. Science depends on our ability to reason, and if materialism is true, reason is an illusion. So far from being an anti-scientific worldview, it is dualism rather than materialism that is the worldview most compatible with science. The real scientific worldview is the one that includes the possibility of rational scientists.
Weighing the arguments for and against the position of dualism, I can only conclude that the physical world is not all there is. There are very strong reasons to believe that the laws of physics cannot possibly explain the existence of our conscious experience. Rather, the very nature of our experience reveals that there is an immaterial component to our existence.
The mind, or soul, or spirit, is real. This belief is supported by many religious teachings, but I hope by now I have shown that it can be arrived at independently of such considerations. Dualism is not a relic of more primitive ages, but a rational and justified belief – and a more complete explanation of reality, compared to philosophical materialism.
This seems to me to be a very important thing to know about ourselves, something that gets to the very core of what we are. As I said early on in my blog, what we believe affects the way that we live. Recognizing our spiritual nature is a significant part of understanding reality, ourselves, and how we should live in it.
There are many questions that I have not endeavoured to answer here, of course. Can the mind or soul survive apart from the body? The radical dependence of the mind on the brain does not make this appear likely from a scientific perspective – though there are other important considerations, and many people find unembodied existence to be intuitively possible. Or, when does the immaterial part of each of us come into existence? The first-person privileged access of mental phenomena makes that a very difficult question to investigate.
But I think that questions like these, and others, are ones that we should investigate. By gaining a better and more complete understanding of ourselves, we can better understand the best way to live in our world.
With that, I am almost done the second major section of my blog. There is one more topic in this section that I want to cover. So in the post after next, I will be writing about certain things of value – the true, the good, and the beautiful.
(First though, since I have covered so much ground, my next post will be a summary of my conclusions, thus far, about the nature of reality.)