In the last post we introduced dualism, the view that a person is something more than his or her physical body. We talked about different versions of dualism, with particular focus on soul dualism, the version of dualism that says a person is essentially a non-physical soul. We considered what might be appealing about such a view – namely, that it allows for the possibility of an afterlife as well as the possibility of not being subject to the laws of nature. We also considered some potential problems with the view: that it doesn’t explain why there are correlations between brain damage and reasoning, that there is something mysterious about how nonphysical mental states could causally interact with the physical states of a particular body, that it’s not clear what sort of organisms have souls and that it’s not clear when during the development of an organism do souls emerge. We didn’t, however, consider any reasons as to why one should believe in dualism. In this post, we will consider an empirical argument for dualism.
Before we consider this empirical argument for dualism, we should remember that there are philosophers who deny dualism and the existence of souls and claim that a person is just a certain physical body (or some part of it, such as a brain) that functions in a certain way. According to this alternative view, a person has mental states, which are located (or “housed” or “supported”) in a certain physical body or some part of it, such as a brain. Since this view says that a person is entirely physical and dualism says that a person is more than something physical, in the debate between the two views, arguably the dualist has the burden of proof.
To say that someone has the burden of proof is to say that he or she has a made a certain kind of factual claim, one that can’t be directly verified by sensory experience, and therefore has an obligation to support that claim. It’s not the obligation of the person who denies the claim to prove the claim false. The reason why the dualist has the burden of proof is that he or she is making the factual claim that there is more to a person that just his or her body. So the dualist has to give a good reason to support dualism. He or she cannot just say “You cannot prove me wrong”. If one cannot give a good reason to support dualism, then no one should take the view seriously.
But what is a good reason for a view? How good a reason is a matter of degree. A reason for dualism might be so good that it’s conclusive. In such a case, you should believe the view. However, a reason for dualism might have some persuasive force, that is, it i might give you some reason to believe the view, but not be conclusive. In such a case, the reason has a certain degree of goodness. Let us therefore say that if a reason is good enough to give you a certain degree of confidence in dualism, then it’s reasonable to accept dualism to that degree. But if a reason doesn’t give you any confidence in dualism, then the person giving it hasn’t met the burden of proof. In such a case, it’s reasonable to believe in physical monism.
According to dualism, a person is not identical with anything physical, such as a particular physical body, or some part of it, such as a brain. What reasons can be given for believing in the existence of something that is not physical? You cannot directly observe something is not physical. However, just because you cannot directly observe something doesn’t mean that you cannot give good reasons to believe in its existence. Observation is not the only way we justify our beliefs about the existence of things. Consider, for example, atoms. When they were discovered, then couldn’t be directly observed. Scientists assumed that atoms exist because by assuming their existence they were able to best explain many of the properties of matter. Perhaps the dualist can employ a similar type of reasoning to try to show that a person is more than his or her body. He can point to some feature that people have been observed to possess and then reason that we need to assume that a person is more than his or her body in order to best explain this feature. If the dualist can do this successfully, then he has given an empirical argument for dualism and met the burden of proof. It is considered an empirical argument because it’s based upon a feature that we know exists through the evidence of sensory experience.
The structure of such an empirical argument can be expressed as follows:
Premise 1: Based on empirical evidence, we know that some people have feature F.
Premise 2: No physical body could have feature F.
Premise 3: If no physical body could have feature F, then there is more to a person than his or her physical body.
Conclusion: There is more to a person than his or her physical body. [Dualism is true.]
PURPOSEFUL ANIMATION: Based on what we observe, we know that some people move around purposefully – i.e. they have purposeful animation. For example, right now I’m typing these words on purpose. So I have purposeful animation. Not all bodies have purposeful animation. For example, corpses do not have have purposeful animation. But the fact that corpses are purely physical bodies without purposeful animation doesn’t show that people are more than their physical bodies. After all, there is a perfect sensible physcialist explanation for why a corpse is not purposefully moving around. It’s because the physical parts of the body of a corpse are not functioning. Moreover, it seems that a purely physical could have purposeful animation. Take a heat-seeking missile, for example. Its body is moving with a purpose, namely to seek out targets that are emanating heat. Is there more to a heat-seeking missile than it’s physical body? No. So it seems that purposeful animation would not be the kind of feature F that the dualist needs to meet the burden of proof.
FREE ACTION: You might reply that a heat-seeking missile is moving around purposefully, but that it’s not freely doing this. In contrast, when people purposefully move around they freely do this. So people are more than their physical bodies because people have free choice, something that a purely physical thing could never have. We will return to this reply in a later post. For now, let me make two brief comments.
First, some philosophers argue that no one freely does anything. They agree that it might feel to you that you sometimes do things freely. But they believe this feeling illusory, just as illusory as the feeling we have that the Earth is not moving. In a later post, I will explain why they believe this.
Second, some philosophers believe that something entirely physical could be freely moving. Consider the second hand of a watch, something that is entirely physical. We say things like the second hand is freely moving around the face of a watch. What we mean (roughly) when we say this is that the second hand is not being obstructed by anything, such as a piece of dirt. If the second hand was stuck, we might say that the piece of dirt prevents it from moving freely. Perhaps we can say something similar about a person who chooses freely, even if a person is entirely physical. What we mean (roughly) when we say that a person is acting freely is that his or her actions are not being obstructed and they caused by his or her desires. Of course, this reply assumes that something entirely physical could have desires. This bring us to the next possible candidate for feature F.
REASONING: Based on what we observe, we know that people reason. Could a purely physical body reason? Some philosophers believe the answer is “yes”. They point to things like chess-playing computers and contend that they are reasoning. They point out that we say things like the computer thinks I’m going to move my queen. It wants me to move out my pawn. It intends to capture my rook. In short, we seem to treat chess-playing computers as as if they are reasoning. Does this mean that it really is reasoning? No. But these philosophers argue that if you think it’s not really reasoning, then you need to give a reason why. If you say that a computer is artificial, something made by people (and machines), you haven’t explained why it’s not reasoning. You need to explain what it is about being artificial that means it’s not reasoning. In a later post, we will discuss a famous argument given by the philosopher John Searle for why he believes that computers could never reason.
PERCEPTION: Based on what we observe, we know that people perceive things. Could a purely physical body have perceptual experiences, such as seeing or tasting? We do have physical machines with sensors that can discriminate colors and tastes. For example, there are simple machines that can put red balls in one basket and blue balls in a different basket. Don’t these machines have to perceive colors in order to do this? If perception is just behavior, then it seems that purely physical machines are perceiving colors. But, intuitively, there seems to be more to perception than behavior. When I perceive some color, the color seems a certain way to me. In other words, I’m conscious of the way the color appears to me, and this consciousness of the color doesn’t seem like behavior. Are machines conscious when they discriminate colors?
CONSCIOUSNESS: Consciousness is a feature of all kinds of perceptual experiences, not just visual experience. When I taste an onion, for example, I’m conscious of the way it tastes. It’s this consciousness aspect of my experience that makes eating so much fun. Yes, I can discriminate the taste of an onion from, say, the taste of orange juice. But a machine can do that. What I don’t think machines have, at least the machines that we currently have, is any consciousness when it “tastes” an onion or orange juice. So perhaps consciousness is the feature that a person possesses, but that no physical body could possess.
We should point out that there are other types of mental states, besides perception, that have consciousness. Sensations and moods and emotions and dreams all can be conscious. It’s not clear whether you could have one of these mental states without consciousness. Could you have a pain, for example, that didn’t feel anyway to you?
Do all mental states have consciousness? It doesn’t seem so. Cognitive states, such as beliefs, are mental states that don’t seem to have consciousness. I can think about my beliefs and so in some sense I can be conscious of them. But I think this type of consciousness is different than the type of consciousness that an itch has. When, for example, I reflect on my belief that 3 is a prime number my belief doesn’t seem or feel any way to me. In contrast, when I have an itch there is a way it seems/feels to me and the way it seems/feels to me is different than the way an pain or a tickle seems/feels to me. According to psychology, many of our mental states are unconscious, and an unconscious mental state, by definition, does not have any consciousness. So if psychology is correct, then not all mental states are necessarily conscious.
What can a one say in response to the idea that consciousness is the feature F that purely physical bodies cannot have? Some philosophers try to argue that we do at present understand how a purely physical machine could have mental states with consciousness. In a later post, we will discuss their reasoning for such a view.
A different response is to concede that we have no idea how a purely physical body could have a mental state with consciousness. But then argue that it doesn’t follow that dualism is true, since it’s also true that dualism cannot at present explain how a person could have a mental state with consciousness. So both the dualst and the critic of dualism are equally ignorant when it comes to understanding how a person could have a mental state with consciousness. But, unfortunately for the dualist, this means that dualism loses. This is because the dualist has the burden of proof. The dualist needs to do more than show that we cannot explain how a purely physical body can have a mental state with consciousness. The dualist has to show that a purely physical body could not have a mental state with consciousness. We may never be able to explain how a purely physical body has mental states with consciousness. But if the dualist cannot explain how a person (not a body) can have consciousness, then consciousness cannot be the feature F that he needs to prove dualism.
NEAR-DEATH EXPERIENCE: If purposeful animation or free will or reasoning or consciousness isn’t the feature F that is going to prove dualism, what about the experiences that many people have claimed to have had when they have been physiologically or psychologically close to death or have been pronounced clinically dead, perhaps due to some sort of trauma to the body, such as cardiac arrest or blood loss? The describe their experiences in similar ways and say things like
- I left my body and then could see my body as I floated above it.
- I could see and hear the doctors tools and hear the doctors talk about what they were doing to try to save me.
- I then floated out of the room, going through walls, and could see 360 degrees other things that were in the environment.
- I entered a tunnel and saw a bright light at the end of it.
- I saw and communicated with loved ones who had passed away.
- I experienced God and felt that I was part of God.
- I had an unpleasant sensation of being yanked back into my body.
- Except for the sensation of being yanked back into the body, the sensation was pure euphoria and serenity and warmth, filled with unconditional love, what I imagine Heaven to be like.
- The experience felt real, not like a dream, which doesn’t feel real.
- The experience was life-changing.
These experiences are called near-dear experiences (NDEs). Perhaps having a near-death experience is something a purely physical body could not have. Watch this 45-minute video about three people describing their near-death experiences.
Here are three more shorter videos of people telling their stories about their near-death experiences.
These near-death experiences are not conclusive empirical evidence for dualism because they might be a result of physical changes in a stressed or dying brain caused by things such as lack of oxygen, effects from anesthesia, neurochemical responses to trauma. While it’s true that science doesn’t have a complete understanding of how the brain produces all the aspects of an NDE, as I pointed out above in the discussion of qualitative aspect, it doesn’t need to. To meet the burden of proof, the dualist needs to show that the brain couldn’t produce an NDE, not that we can’t explain how it can do it.
Given that there is an alternative physicalist explanation for NDEs, they do not provide conclusive empirical evidence that dualism is true,. However, as I pointed out in the beginning of the post, a reason might have merit even if it’s not conclusive. And there are at least two things about NDEs that might give dualism some support. First, it seems that dualism is true, if a person has an NDE when his or her brain is inactive, and there are studies that indicate that a person can have an NDE even when no brain activity can be measured. Second, people claim that NDEs seem veridical (i.e. truthful) and do not seem like dreams or hallucinations. If a person thinks his experience of seeing a dead relative is veridical, then this should count as some evidence that the experience is veridical. These two reasons aren’t very strong. It’s not clear whether the tools with which we measure brain activity are sufficiently precise to register all brain activity. And it’s not clear how good people are in determining whether an experience is veridical. Athough these reasons aren’t very strong, they still may have sufficient strength to accept dualism on a tentative basis. To what degree should you tentatively accept dualism? I’ll let you decide.
