Interdisciplinary Perspectives on Materialism and the Value of Conscious Life

Apart from the time devoted to collaborative reading sessions during Ordered Universe Symposia, there is also room for broader conversation and exchange of ideas. These conversations are very interesting and maybe also quite unusual, as they represent a rare instance of academics from very different disciplines being brought together. Interdisciplinary discussions are challenging in many ways and they require trust and respect on both sides. It is wonderful to see how during Ordered Universe Symposia, an atmosphere of open-mindedness and friendliness is all around so that this kind of true interdisciplinary exchange becomes possible.

Another reason for why interdisciplinary discussions can be challenging is that sometimes different disciplines approach the same issue from very different angles, with different underlying assumptions and goals. In such instances, it can be difficult to understand why the other party has qualms with what one the other considers completely unproblematic. Nonetheless, these situations bear the potential to encourage taking a step back, thinking about whether one has so far been missing an aspect that is actually quite relevant to the issue in question. Here, I want to talk a bit more about one such issue that is of interest to both scientists and humanities, namely the mind/body problem.

To set the scene, let me start with some philosophy. The mind/body problem is a metaphysical problem about the nature of the relationship between body and mind, and it has spurred philosophical thinking for hundreds of years. In our times, it’s mostly applied to the relationship between brain and mind. By mind, we mean our phenomenological experiences, and one might also want to use the term ‘consciousness’ here. To make it more concrete, processes of the mind span all conscious experiences we have, from perceiving aspects of the natural world, for example, having the sensation of seeing something red, all the way over having specific thoughts to feeling emotional states, like being happy, relieved, disappointed, angry, or sad.

With regard to what precisely the nature of the relationship between brain and mind is, there is a debate mainly between two philosophical positions. Materialism is a form of monism that assumes that all there exists is the brain, and our phenomenological experiences, be they perceptions of the natural world, thoughts, or emotional states, are fully reducible to the physical states that constitute the brain. In other words, all mental states are thought to be nothing but brain states. To the contrary, dualism postulates that mind and brain exist alongside each other. They are different substances so that one cannot be reduced or explained by the other; nonetheless, there might be some sort of link between them.

Somewhere in between materialist and dualist positions, so called supervenience claims have been posited. The claim that mental states supervene on brain states says something like this: When all neural states have been specified all mental states have been fixed. However, mental states are not reducible to brain states but have existence properties above and beyond the brain states through which they have been fixed. For an illustration of what supervenience means, imagine an arrangement of dots that together create the figure of a for example a human face. Once the dot arrangement is fixed the face follows; but,  the face has properties that go beyond the properties of the dots. For instance, a Martian unfamiliar with how human faces look like would perceive a pattern of dots but not the face. It would be possible to say then  that the face supervenes on the dots.

Scientists could say that this is all very interesting, but belongs to the realms of philosophy and hence is nothing they need to consider in order to be good scientists. However, it seems that the mind/brain problem is hugely relevant to all disciplines that either study cognitive processes or neural mechanisms, and this applies not only to neuroscientists but also to most psychologists and also to some biologists and linguists. The reason why the mind/brain problem is relevant to them is that the answer one adopts fundamentally influences the conclusions one feels entitled to draw: A materialist scientist can claim that by elucidating neural computational mechanisms, they at the same time generate answers to how the mind works, simply because the mind can be fully reduced to what is going on in the brain. A dualist scientist, on the other hand, is constrained to the much more humble conclusion that her elucidation of neural processes explains something about how the brain operates, but it cannot tell us about the mind, that is, about why we have the phenomenological experiences we have, think the thoughts we think, and feel what we feel. Thirdly, someone who makes a supervenience claim would be able to say that research findings about neural mechanisms can tell us something about mental processes, in the sense that changes in neural states always come with changes in mental states. Nonetheless, as mental states have existence properties that cannot be reduced to neural processes, the precise nature of these mental states cannot be found out about through neuroscientific investigations.

What has repeatedly struck me is that people who are heavily involved in neuroscience generally do not talk about the mind/brain problem, and the vast majority of research papers on fMRI, EEG or related techniques do not even mention these fundamental questions. The second thing that is striking is that those scientists who do talk about how mind and brain are related sometimes assume with rather high levels of certainty that materialism is true. Why materialism is an attractive position to hold for cognitive scientists becomes clear when one considers the metaphors they use and the goals they are trying to achieve. In cognitive science, mind and brain are often compared to a super computer, and researchers aim to understand the nature of its hardware and the algorithms implemented, the overarching goal being the development of mechanistic accounts of how mind and brain operate. To think of mind and brain as an organic computer-like machine, then materialism is an obvious position to adopt. Furthermore, the monist aspect in materialism comes in handy as only one substance, that is, physical substance, is what researchers need to concern themselves with. By contrast, the adoption of dualist or supervenience claims adds to the picture another kind of substance with different existence properties. This would bring with it a whole new level of complexity that would make things even more difficult to get to grips with.

That scientists are tempted to be materialists is hence understandable, and in any case materialism is not at all an unreasonable position to adopt. However, it seems that scientists who implicitly or explicitly hold materialism to be true often have not thought about the range of difficult consequences this position entails. For a philosopher, by contrast, it goes without saying that any serious materialist should have grappled with the difficulties of materialism before deciding that this is the position he wants to follow.

One of the consequences of materialism that might be difficult to deal with relates to the sort of implications a materialist position might have for questions about whether there is any special value to human life, or, to keep it more general, to any form of conscious life. Consciousness is a term connected to mental states, and according to the materialist, mental states are nothing but brain states, and that is, physical states. Now, let’s hold this for a moment and add to this picture issues concerned with morality. Moral rules tell us which actions are good vs. bad. Generally, we apply them to some entities but not others, and importantly the distinction between these two categories of entities is not a moral but a metaphysical one. For instance, our moral intuition suggests that it’s bad to kill a human being but acceptable to log down a tree, and the relevant difference between human beings and trees is often taken to be that humans have consciousness (or at least the potential to have it) and trees do not. If we now go back to how the materialist conceptualises consciousness (namely as nothing but physical states), then it becomes difficult to see how the physical states that make up a tree differ in relevant ways from the physical states that make up a human, with the consequence that it’s acceptable to destroy one but not the other.

At this point, there are two routes open to the materialist: (1) he or she bites the bullet and accepts that there is no relevant metaphysical difference that distinguishes conscious from non-conscious life. Logging down a tree and killing a human being would then have the same moral status. (2) He or she tries to identify aspects that distinguish conscious from non-conscious life and that do not draw on consciousness as the differentiating property. I assume that option (1) will be contrary to many people’s moral intuitions. Option (2) allows for retaining the notion that conscious life is particularly precious and that it is morally wrong to destroy it. To make option (2) work, the materialist could try to argue that conscious life is special not because it differs from non-conscious life in substance (both ultimately consist of physical states) but because of the specific physical states that are what we refer to as consciousness. If he goes down this line, the materialist would probably suggest that the more complex physical states become, the more special or valuable they are and the more wrong one does when one destroys them. Human beings would be seen to be more complex than trees and therefore killing a human would be morally wrong in a way that logging down a tree would not.

It might be possible to get this argument to work, but nonetheless it seems to me that it misses the point. Intuition suggests that conscious life is special because it is conscious, not because its degree of complexity exceeds a certain cut-off. This would entail that the materialist has not managed to square his position on the mind/body problem with his moral intuitions. More generally, I think in this particular instance scientists interested in mind and brain would benefit a lot from taking seriously what philosophers, in particular amongst humanities experts, have said about the mind/brain problem. Engaging philosophically with how mind and brain are related would certainly enrich the way scientists frame their big-picture questions, it would influence how they interpret their data and the long-term goals they set themselves. I think this discussion is a case in point in how interdisciplinary exchange allows people to question their assumptions and to incorporate into their thinking perspectives from other disciplines. I believe that this process relevantly enriches the frameworks within which we conceptualise what we do, and that it prevents us from settling overly quickly for answers that might be comfortable but which do not represent, necessarily, the complexity with which we chose to concern ourselves.