Neuroscience and the Soul

The Human Person in Philosophy, Science, and Theology

Thomas M. Crisp, Steven Porter, Gregg A. Ten Elshof

• Éditeur: Eerdmans
• Année: 2016
• ISBN:
  9781467445658
• Sujet: Theology & Religion
• Sous-sujet: Philosophy of Religion

An interdisciplinary look at arguments both for and against traditional belief in the soul It is a widely held belief that human beings are both body and soul, that our immaterial soul is distinct from our material body. But that traditional idea has been seriously questioned by much recent research in the brain sciences. In  Neuroscience and the Soul  fourteen distinguished scholars grapple with current debates about the existence and nature of the soul. Featuring a dialogical format, the book presents state-of-the-art work by leading philosophers and theologians—some arguing for the existence of the soul, others arguing against it—and then puts those scholars into conversation with critics of their views. Bringing philosophy, theology, and science together in this way brings to light new perspectives and advances the ongoing debate over body and soul. CONTRIBUTORS:
Robin Collins
John W. Cooper
Kevin Corcoran
Stewart Goetz
William Hasker
Veli-Matti Kärkkäinen
Eric LaRock
Brian Lugioyo
J. P. Moreland
Timothy O'Connor
Jason D. Runyan
Kevin Sharpe
Daniel Speak
Richard Swinburne
 

PART 1

Recent Debate in Philosophy about the Mind-Body Problem

CHAPTER 1

Do My Quarks Enjoy Beethoven?

William Hasker

Do my quarks enjoy Beethoven? Perhaps that seems to you a strange question. If you were able to make any sense of it at all, you most likely thought of it as a rather extreme metonymy—a way of asking whether I enjoy Beethoven, somewhat as if someone had asked whether my taste-buds enjoy a medium-rare filet mignon. If that were the intended meaning, the answer would be an emphatic Yes—to both questions. In fact, however, I intended the question quite literally, as a question about the quarks in my body—those tiny particles that, combined in certain ways, make up the protons and neutrons that, together with electrons, compose the atoms that constitute that body. And my question is, do those quarks enjoy Beethoven, or don’t they?

Given this, however, you may be returned to your initial state of bafflement, unable to understand the question in any sensible way. Nevertheless, I shall attempt to show you that the question is indeed deserving of our attention, at least if we have the aim to gain an understanding of the human mind. My project in this essay is to develop that puzzling question with reference to the philosophical view known as materialism. More precisely, the view to be considered is the doctrine of material composition—the claim that human beings, and other sentient organisms, consist of the physical stuff of the world and of nothing else. Now the doctrine of material composition is less demanding than some other views that go under the label of materialism. It does not require us to accept that there are no mental properties or mental states, or that mental properties are reducible to physical properties, or that mental states and properties have sufficient causes that are entirely physical in nature. All of these commitments are required by some of the currently popular forms of materialism, but material composition as such does not require them, though it is consistent with all of them. So material composition is a comparatively undemanding materialist view, and yet I will show that, when interrogated in terms of our question, it yields some extremely interesting results.

This paper has three parts. In the first part, I develop a version of compositional materialism, termed the theory of emergent material persons (EMP). This theory is largely based on the views of John Searle; towards the end I bring in some ideas from Timothy O’Connor. In the second part, I investigate further the EMP theory. First, I develop some implications of the theory concerning causation of and by mental states. Then, I raise the question: according to this theory, what is the subject of experience? It is here that the question about my quarks and Beethoven comes to the fore. A brief final section sums up the results and points to some direction for future research.

The Theory of Emergent Material Persons

We begin, then, by examining some ideas of John Searle. Searle is notable in that he is a committed naturalist who has nevertheless set out an unusually full and insightful account of the nature of consciousness.¹ Our task will be to see how he manages to accommodate this account of consciousness within his naturalistic commitments, including compositional materialism. For his account of consciousness, we may usefully begin with his article, “The self as a problem in philosophy and neurobiology.” He begins with a definition: “consciousness consists of those states of feelings, sentience, or awareness that typically begin when we wake from a dreamless sleep and continue throughout the day until those feelings stop, until we go to sleep again, go into a coma, or otherwise become ‘unconscious’ ” (Self, 141). This of course is not a scientific analysis; it merely “locates the target of our investigation,” but as such it is hard to fault. He goes on to point out three essential features of consciousness:

1. “Conscious states . . . are qualitative in the sense that there is always a certain qualitative feel to what it is like to be in one conscious state rather than another” (Self, 141).
2. “[C]onscious states are subjective in the sense that they only exist as experienced by a human or animal subject. Conscious states require a subject for their very existence” (Self, 141-42). The same point can be made by saying that these states have a “first-person ontology.”
3. Conscious states are unified: “Conscious states always come to us as part of a unified conscious field.” “[W]hen I am listening to Beethoven’s Ninth Symphony while drinking beer, I do not just have the experience of listening and the experience of drinking, rather I have the experience of drinking and listening as part of one total conscious experience” (Self, 142).

These three features, moreover, are closely connected to each other: “You cannot have a qualitative experience such as tasting beer without that experience occurring as part of some subjective state of awareness, and you cannot have a subjective state of awareness except as part of a total field of awareness. . . . So we might say, initially at least, the problem of consciousness is precisely the problem of qualitative, unified subjectivity” (Self, 142).

A further important point made by Searle is that, as we consider these features of consciousness, we are forced to regard the subject of experiences as a “non-Humean self.” “In order to make sense of our experiences,” he tells us, “we have to suppose,

There is some x such that

x is conscious;

x persists through time;

x has perceptions and memories;

x operates with reasons in the gap [i.e., between motives and the decision to act];

x, in the gap, is capable of deciding and acting;

x is responsible for at least some of its behavior” (Self, 148).

Searle insists, however, that this x is merely a “formal feature” of the conscious field, not a separate entity distinct from that field: we have to guard against “sounding like the worst kind of German philosophers (Was ist das Ich?)” (Self, 148).

Clearly, more could be said about each of these features of consciousness, but our present question is, how does Searle go about fitting them into his naturalistic worldview? As a first move, Searle repudiates the dichotomy between mental and physical states and properties, and with it the “property dualist” label that some readers have tended to attach to his views.² Conscious states are biological states; they are states of a biological (and therefore physical) organism. Mental properties are “higher-order” properties, grounded in the basic biological properties of the organism, in much the same way that solidity is a higher-order property of a physical object. When the molecules of an object are bound together in a certain way, so that they resist deformation and penetration by other objects, the object is said to be in the “solid state.” Similarly, when a biological organism is functioning in a certain way—a way that as yet is not well understood, though it is being intensively studied by neuroscientists—the organism is in a certain conscious state. This can be described as a case of emergence, but it is an uncontroversial and relatively unexciting sort of emergence, one that is perfectly familiar in contexts unrelated to the mind and consciousness.

This parallel between mental properties and higher-order physical properties such as solidity does important work for Searle in his project of incorporating consciousness within his naturalistic worldview. But there is a significant difference between the two cases. Solidity and other higher-order physical properties are both ontologically and causally reducible to the microphysical base properties. When the molecules of a certain quantity of matter stand in such-and-such relations, it is in principle deducible that the matter in question will exhibit the behavior characteristic of solidity. Solidity, we can truthfully say, is “nothing but” those molecules standing in those relations to one another. And in general, the causal properties of the solid object are wholly deducible from the causal properties of the molecules, etc. of which it is composed. With consciousness, the situation is somewhat different. Mental properties, as was explained above, have a “first-person ontology”; that is to say, they can exist only as perceived by a subject. This is not true of the physical properties of the organism, and because of this mental states and properties are not deducible from, nor are they ontologically reducible to, the physical base properties. However, Searle holds that they are causally reducible; all the mental properties, events, and so on are completely accounted for in terms of the causal powers of the biological base properties. And this, he believes, is sufficient to enable his project of “biologizing” the mental to go through. He states: “from everything we know about the brain, consciousness is causally reducible to brain processes; and for that reason I deny that the ontological irreducibility of consciousness implies that consciousness is something ‘over and above,’ something distinct from, its neurobiological base” (Self, 156).

An important advantage Searle claims to derive from his view is that problems concerning epiphenomenalism, causal closure, and the like simply do not arise for him. He states, “Of course, the universe is causally closed, and we can call it ‘physical’ if we like, but that cannot mean ‘physical’ as opposed to ‘mental’; because, equally obviously, the mental is part of the causal structure of the universe in the same way that the solidity of pistons is part of the causal structure of the universe; even though the solidity is entirely accounted for by molecular behaviour, and consciousness is entirely accounted for by neuronal behaviour” (Self, 157). No one objects on this account that solidity is epiphenomenal, so why is there a worry about consciousness as epiphenomenal? “Consciousness does not exist in a separate realm and it does not have any causal powers in addition to those of its neuronal base any more than solidity has any extra causal powers in addition to its molecular base” (Self, 158).

It may occur to us that Searle is moving a bit swiftly. If consciousness is not ontologically reducible to brain processes, it seems that only two alternatives are available: consciousness is something other than (“over and above”) brain processes, or consciousness does not exist at all—and the latter option has clearly been ruled out. If consciousness involves properties other than the familiar physical and biological properties, the question does arise whether those additional properties convey any causal powers other than those that are entailed by the non-mental properties of the organism.³ On the face of it, Searle’s answer to this would seem to be “No”—he does, after all, affirm causal closure—and if so, the problem of epiphenomenalism seems to have returned.

In fact, Searle is himself forced to confront this problem, or a very similar problem, because of an additional feature of our conscious experience that has not been emphasized up until now. That is the experience of the “gap”—the “open space” in which decisions are made, without (apparently) being determined by anything that has gone before. Searle has long been aware that our experience as agents seems to provide support for a libertarian understanding of free will. “For example, it seems that when I voted for a particular candidate and did so for a certain reason, well, all the same, I could have voted for the other candidate all other conditions remaining the same” (Free Will, 39). Furthermore, Searle believes that this “seeming” is deeply embedded in our experience as agents, so much so that we cannot really free ourselves from it even if we come to accept determinism as the truth. In his early work, Minds, Brains, and Science,⁴ he was content to suppose that this impression of freedom is, in effect, a trick played on us by evolution, a persistent illusion which we cannot in practice overcome even when in theory we recognize its illusory character. But this is at best an uncomfortable position, and more recently he has come to entertain seriously the possibility that the intuition of freedom might be veridical.

A helpful discussion of this possibility is found in Searle’s paper, “Free will as a problem in neurobiology.” Consider the following situation: a person makes a decision that seems to be “free” in the sense described above. The person is aware of various motives for and against the decision actually made, but the motives do not seem to be causally sufficient to bring about the decision. Rather, there is a gap between the antecedent situation and the decision, and this gap is filled by the person herself, actually making the decision. By hypothesis, the conscious experience of making the decision is a higher-order property of the person’s brain, which both causes and realizes the conscious states involved. Now, here is the question: Is the brain-process which causes and realizes the conscious decision-making itself deterministic in character, as most scientists and many philosophers would assume? Or is there also a gap on the neurobiological level, corresponding with the gap consciously experienced by the agent?

One possibility, the one Searle thinks most neurobiologists would assume to be the actual case, is that the brain-process is indeed deterministic. Searle, who apparently once accepted this view himself, now finds it to be problematic:

But this is intellectually very unsatisfying, because it gives us a form of epiphenomenalism. It says that our experience of freedom plays no causal or explanatory role in our behavior. It is a complete illusion, because our behavior is entirely fixed by the neurobiology that determines the muscle contractions. On this view evolution played a massive trick on us. Evolution gives us the illusion of freedom, but it is nothing more than that—an illusion (Free Will, 62).

Note how the problem of epiphenomenalism, which supposedly had been banished by the view of consciousness as a higher-order property, now makes its reappearance. From now on I shall refer to this option as the illusory-freedom hypothesis.

But if this view is unsatisfying, what is the alternative? The key assumption in the alternative real-freedom hypothesis, and the one that creates the difficulties in formulating it coherently, is that the experience of freedom is not epiphenomenal, that consciousness as such, and our conscious decision-making, really make a difference in the functioning of the physical organism. In order to grasp this, we have to think of consciousness as a “system feature,”⁵ one that is “literally present throughout those portions of the brain where consciousness is created and realized” (Free Will, 63). Further, we have to suppose that “the logical features of volitional consciousness of the entire system”—that is, I take it, the syntactic structure, semantic contents, affective components, and so on of the conscious state—“have effects on the elements of the system” (Free Will, 63). This hypothesis, then, involves three claims:

First, the state of the brain at t₁ is not causally sufficient to determine the state of the brain at t₂ (Free Will, 64).

This is necessary to provide the gap in the chain of physical causation which is needed to match the experienced gap in the mental decision-process, thus allowing roo...