Metaphysics and the mind/body problem

If you have browsed through the shelves of popular book stores such as Barnes and Noble, you may have come across a section labeled metaphysics. Within this section, there are books about witches, UFOs, ghosts, and crystal healing. Within the academic study of philosophy, metaphysics deals with very different kinds of topics. In this post, I will explain what philosophers mean by ‘metaphysics’ and compare it to the science of physics. I will also argue that theories in physics—as well as the other sciences—make metaphysical assumptions. 

Metaphysics deals with questions about the nature of reality. Here are some of them:

Ø  Why is there something rather than nothing? 

Ø  What is the relation between minds and brains? Are minds and brains one and the same? Can minds exist without brains or are they dependent upon them?

Ø  Are future events just as real as the present or the past events? 

Ø  Do numbers exist?

Ø  What is the world ultimately like? Does science give us a complete and accurate description of what there is, or is there much more to reality that what we can observe? 

 The word ‘metaphysics’ goes back to the time of Aristotle, translating roughly to beyond or after physics. While I have not heard the discipline of metaphysics characterized like this before, I think that it can also be understood as a prequel to physics. Before engaging in theories about the physical world, you will likely need to have some views about the nature of reality. Reality is what the world is really like, whereas science tells us about the observable physical world. One may ask what the difference is between the observable world and reality. Aren’t they the same thing? Plato often made a distinction between appearance and reality. Large buildings may look very small when we are far away, but they in fact aren’t. Science gives us better tools for examining the world and its contents, but those appearances may be deceiving as well. The world may be very unlike how our current (and future) scientific theories describe it to be, and it is possible that we may not be able to know what the world is really like. Putting such skeptical worries aside, it is still intelligible to say that there are (deeper) facts of the matter. There is a way that the world is, and metaphysics is a discipline that actively tries to figure out the details.

 Rene Descartes in his book ‘Meditations’ tried to establish a firm foundation for science by reflecting upon the metaphysical views one may think it presupposes. For instance, science presupposes that there exists a physical world (made up of discrete objects) that is external to the minds of human beings. Descartes tried to defend such views by appealing to the existence of God, whereas philosophers such as George Berkeley tried to deny them, maintaining that everything that exists is mental in nature. On Berkeley’s view, there simply are no objects ‘out there’ in the world, it’s all in our (and God’s) mind. Likewise, philosophers such as Spinoza deny that the world is made up of discrete objects. On Spinoza’s view, there is only one thing in the world—the universe itself. The universe is comprised of many (possibly infinite) parts, and passes through various stages (or as Spinoza called them ‘modes’), but it is ultimately one highly complex object. The views of Berkeley and Spinoza may sound very outlandish, but it a matter of ongoing scholarly debate as to where exactly they go wrong (if they do at all). With respect to 1) whether the world is physical or mental, and 2) whether the world is one or many objects, science can carry on undisturbed. The truth or falsity of such metaphysical theories can be thought of as running parallel to scientific theories. Scientists may sometimes rightfully ignore metaphysical issues, but there are instances where science runs deep into metaphysical waters. 

Two of our best scientific theories (i.e. quantum mechanics and general relativity) run into problems of interpretation. By problems of interpretation, I mean that the experimental data is compatible with a multitude of metaphysical hypotheses (11 to be exact). To give just two examples, the many worlds interpretation states that there are an infinite number of branching universes, whereas the Bohmian interpretation states that there is only one universe. At the moment, it is thought by many physicists and philosophers that there is (in principle) no scientific test or observation that could favor one interpretation over another. But surely, only one of these interpretations can be correct. The world can only be one way. There have been different reactions to the problem of many interpretations. Some scientists reserve judgment, others argue for one interpretation over the others, and some adopt a position known as ‘instrumentalism’. Instrumentalism states that science is in the business of making accurate predictions and models, not informing us what the world is really like. Perhaps the instrumentalists have got this right. If science cannot tell us what the world is really like, maybe metaphysics and philosophy can. 

It is believed that most (if not all) metaphysical questions are to be solved through careful thought and logical analysis, rather than through observation and experimentation, two of the central investigatory tools of science. Scientific findings may inform the discussion, but they rarely answer metaphysical questions by themselves (*though most scientists believe the exact opposite is true!). Metaphysical views are compared with one another in terms of their overall plausibility, their compatibility with other theories, logical coherence and on measures of elegance and simplicity. To understand how metaphysical debates are carried out, I will focus on the relation between the mind and the brain. If we are to appeal to science alone, what kind of experiment or observation might determine whether minds and brains were one and the same?

 Let’s say that future scientists perfect brain imaging. Furthermore, let’s stipulate that such technology allows scientists to pinpoint the source in the brain for all mental activity. Your emotions are correlated with brain activity in region X, while your personality and moral character are correlated with brain activity in region Y, and so on. Could we conclude from such observations that the mind is simply identical to the brain, and that, for instance, there is no immaterial soul? Not from experimental data alone. Even perfect correlations between brain activity and mental activity do not establish causality, though it does provide one with good reason for thinking they are causally connected. Substance dualists, whom believe that the mind and brain are distinctly different kinds of things, will argue that the experimental data shows how the physical brain is affected by the immaterial soul. It doesn’t conclusively demonstrate that there is no soul. 

How can one rule out the possibility for there to be a soul causing all of the activity in the brain? Since the soul is said to be immaterial—i.e. not located in space—there would be no way to scientifically test for its presence. Instead of relying upon experimental data or observations, philosophers have offered several arguments for why there probably isn’t an immaterial soul. The first style of argument appeals to scientific theories and laws. It is argued that 1) the alleged causal interactions between souls and brains violate laws of conservation of energy and 2) are in conflict with Einstein’s relativity theory. 

A second style of argument is conceptual in nature. Such arguments question the coherence of mind-to-brain causation. If a mind is not located in space, and is not made up of anything physical, how does it interact with a physical brain located in space? Let’s suppose that the soul causes the brain to feel guilty about an immoral action. We can give a nice story about what goes on in the brain during such an experience, but what happens before the moment of soul-to-brain interaction? How does the soul initiate the sequence of brain activities? In everyday causal interactions (e.g. knocking over a glass of wine), objects typically interact through direct contact. My hand makes contact with the glass and then the glass falls off the table. But it doesn’t really even make sense to say that the soul ever “contacts” the brain since the soul does not occupy any space. The soul must interact with the brain in some other way. But given that the soul and brain have no properties in common (other than existing in time), it is hard to see how any kind of interaction is possible. Rene Descartes, an early proponent of substance dualism, conceded that this problem of causal interaction was a powerful objection to the view, and ultimately, was unable to give a satisfactory reply. At this point, a dualist might appeal to mystery. Just because we do not know how the causal interaction is possible doesn’t mean that it’s impossible. Soul-to-brain causation might just be beyond human comprehension.  

Lastly, a third style of argument appeals to a principle of logical reasoning called Occam’s razor. Occam’s razor states that you ought not multiply entities beyond necessity. Put in everyday English, if you have a theory that explains everything by positing one thing (e.g. the brain), then you shouldn’t posit something else (e.g. a soul) in addition to it. Positing additional entities runs the risk of error. A theory is more likely to go wrong if one starts adding extra parts that are unnecessary. For example, take a theory of electricity that appeals to electric demons. The theory is otherwise identical to modern theories of electricity, but insists that the flow of electricity is maintained by sprinting immaterial demons. What should we make of such a theory? It is clearly absurd to posit such entities to a theory because the demons don’t add anything to the explanation. If anything, they just complicate it for no good reason. The same is thought to be true of the addition of a soul to modern psychological and neuroscientific theories. Scientists and philosophers alike argue that we can explain everything without positing a soul on top of the highly complex organ that is the brain. Dualists might insist that there are certain things that psychology and neuroscience leave out. For instance, our subjective experience of the world. How can brain cells and chemicals give rise to consciousness? 

In closing, I have argued that there a subset of meaningful questions that science alone cannot answer. The distinction I’ve implicitly made between science and philosophy may be challenged. I’ve taken science to comprise the activities that scientists regularly engage in (e.g. observation and experimentation), and metaphysics—as a sub-branch of philosophy—to be the activities that philosophers regularly engage in (e.g. conceptual analysis, logical reasoning). I do not want to say that there isn’t a great deal of overlap between science and philosophy. On the contrary, I think that the two disciplines are entangled together. There are times in which we are all philosophers, and times in which we are all scientists. Philosophy and science are intellectual activities that human beings practice to better understand the world and their place in it. When we entertain purely metaphysical questions, we have our philosopher’s cap on. When we perform experiments, make predictions, or analyze data, we have our scientist’s cap on. Metaphysical questions have been lingering for millennia and offer no easy solutions. But each of us will likely find one of the (many) solutions to be plausible or, at the least, not as crazy as the rest. 

Free will and moral responsibility

On Halloween night, a man in a white mask goes door-to-door killing everyone in his sight with a large kitchen knife. He is arrested and brought in to trial. On a scale from 1 to 10 (1=not at all responsible, 5=somewhat responsible, 10=fully responsible), how responsible would you consider the man to be for his actions in light of the three following scenarios:

a)      The man was possessed by evil spirits

b)      The man was psychopathic with a severe self-control deficit

c)      The man planned everything and knew that his actions were immoral

If you think that the man wasn’t responsible in (a), but near fully responsible in (c), on what basis did you come to such judgments? Common sense says that the man who planned everything is responsible because he made the decision to kill all of those people whereas the man under possession did not. We consider ourselves to be responsible for those actions under our control. We do not blame small children or non-human animals for their actions because they are lack certain mental capacities (e.g reflective reasoning) and/or knowledge (e.g. moral norms) that allow for reason-guided action. It seems then that moral responsibility depends on whether or not we can freely act or make decisions, otherwise known as free will.

A view held by many scientists (and some prominent philosophers) rejects this common sense picture. Free will skepticism (FWS) entails that 1) no one has free will and that 2) no one is responsible for anything. If we are not morally responsible for our actions, then the correct answer for (a-c) should be a (1). The man who planned everything and knew his actions were immoral was no more responsible than the man who had all of his actions manipulated by evil spirits. 

FWS has radical implications for our moral, legal, and social practices. Unlike certain abstract philosophical questions (e.g. whether numbers exist), the free will debate is of real world significance. In this post, I will assess the plausibility of free will skepticism and defend compatibilist theories of free will—which I take to preserve many of our moral, legal, social practices—from recent attacks. Before I get into the details, I’d first like to state that the free will debate is deeply interconnected with many other philosophical topics (e.g. the nature of causation, philosophy of action, the mind-body problem, and laws of nature) for which there are no easy or obvious answers. In taking a side in the free will debate, one must tacitly accept views regarding all of these other topics. Likewise, the free will debate itself comprises a number of different questions:

·         What is free will?

·         Is free will compatible with determinism?

·         Is free will required for moral responsibility? 

·         What is moral responsibility? 

·         What follows if we don’t have free will and/or moral responsibility?

Free will can be conceived of in more than one way. There is first, the libertarian conception of free will, which states that free will gives us ultimate control of our actions or the unconditional ability to do otherwise. Possession of libertarian free will entails that if we were to rewind the clock right before the moment of some action (e.g. eat cereal for breakfast)—*fixing all of the past conditions (e.g. mental states, prior events, etc.)*—we would be able to do otherwise (e.g. eat eggs for breakfast). This conception of free will often goes hand in hand with dualism—the view which states that the mind and body are independent—as well as theism (1). Under a theistic reading, free will can be thought of as a god given power, giving humans ultimate responsibility for their actions. Many scientists and philosophers doubt that we have this kind of free will. Without this kind of free will, it is thought that humans are just like billiard balls, with each action the result of a long chain reaction of past events constrained (or determined) by the laws of nature. But there is also the compatibilist conception of free will, an alternative that’s been around since Ancient Greece (2).

Compatibilism states that we can have free will even if the universe, and our actions, are the result of past events and the laws of nature. In a nutshell, compatibilism is the view that we can be morally responsible even if we lack immaterial souls or magical causal powers. Hume thought of free will as the ability to make decisions without any external constraints (e.g. having a gun up to your head) (3). Eddy Nahmias, a contemporary compatibilist, conceives of free will as a set of psychological capacities (4). Such capacities include: self-control, future planning, and rational deliberation. The extent to which an agent has free will depends on whether there are any internal (e.g. mental illness) or external (e.g. gun to head) pressures working against these capacities. On this view, free will is not an all-or-nothing feature, but rather, a matter of degree. 

Many have challenged compatibilist theories on the grounds that their proponents are changing the subject. Free will skeptics claim that most people (i.e. non-philosophers) have the libertarian conception in mind, and that therefore, it is then misleading to say that we have free will, but of a different kind. Sam Harris gives a nice way to illustrate this objection.

“Imagine that we live in a world where more or less everyone believes in the lost kingdom of Atlantis. You and your fellow compatibilists come along and offer comfort: Atlantis is real, you say. It is, in fact, the island of Sicily. You then go on to argue that Sicily answers to most of the claims people through the ages have made about Atlantis. Of course, not every popular notion survives this translation, because some beliefs about Atlantis are quite crazy, but those that really matter—or should matter, on your account—are easily mapped onto what is, in fact, the largest island in the Mediterranean. Your work is done, and now you insist that we spend the rest of our time and energy investigating the wonders of Sicily” (5).

For Harris’s analogy to work, one must assume that everyone more or less believes in the libertarian conception of free will. This is an empirical question, one that, at best, remains unsettled (6). But let’s assume for the sake of argument that most people do have the libertarian conception in mind. Does it follow that we should then conclude that free will does not exist? Another option would be to state that the folk are simply wrong about the nature of free will. We wouldn’t want to say that energy doesn’t exist simply because the folk conception of ‘energy’ is erroneous. What’s relevant is whether the concept maps onto something in the world, not how many people happen to misunderstand it. There are further, pragmatic, reasons for siding with the compatibilists. 

It would be absurd, if not impossible to give up talk of moral responsibility altogether. As human beings, we have emotional reactions to certain kinds of behavior (7). We feel indignation towards those who do us wrong and we feel gratitude towards those who help us. If no one is morally responsible, then no one deserves blame or praise. It would thus be irrational to experience such reactive emotions and we would be rationally compelled to try and eliminate them from the human experience. Unless we come to the point where drugs and genetic modification can rid us of such emotions, I think they are here to stay. 

In summary, there are roughly three positions one may take up in the free will debate. One can be a libertarian, a skeptic, or a compatibilist. I have argued that compatibilism is the most appealing option, on the grounds that it preserves our common sense intuitions about moral responsibility (which may be part of our human nature), but this is far from a knock-down case for the view. There is much more to say about all three of these views. In the future posts, I will dive much deeper into many of the questions raised here. I will focus mainly on the debate between free will skeptics and compatibilists and ultimately argue that compatibilism is the more plausible view to hold. 

Works cited:

(1)   Not all libertarian views are religiously motivated. For example, the philosopher Robert Kane defends a naturalistic theory of libertarian free will. See his 1998 book, “The significance of free will”, for an articulation and defense of his view. 

(2)   Scholars have argued that ancient Stoics, such as Chrysippus, advanced compatibilist theories. Sharples, R. W. (1983). Alexander of Aphrodisias on fate: Text, translation, and commentary. Duckworth.

(3)   http://plato.stanford.edu/entries/hume-freewill/

(4)   http://opinionator.blogs.nytimes.com/2011/11/13/is-neuroscience-the-death-of-free-will/?_r=0

(5)   https://www.samharris.org/blog/item/the-marionettes-lament

(6)   Murray, D., & Nahmias, E. (2014). Explaining away incompatibilist intuitions.Philosophy and Phenomenological Research, 88(2), 434-467.

(7)   The philosopher Peter Strawson has written extensively about the relevance of emotions to the free will debate. See his classic text Freedom and resentment (1963).

Further reading:

http://plato.stanford.edu/entries/compatibilism/

http://plato.stanford.edu/entries/freewill/

Recommended films with connections to the free will debate:

The Adjustment Bureau

Minority Report

A Clockwork Orange