#42 God and Neuro-Science

Dr. craig’s response

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To answer this week’s question, I’ve asked Prof. Michael Murray of Franklin and Marshall College, who has been studying this area in some depth, to write a guest Question of the Week. Here is Prof. Murray’s response:

Godfrey raises two distinct issues here, and we must consider them separately. The first issue actually has two parts:

and

The second issue is this:

Let’s consider these in turn.

Until the twentieth century, the vast majority of (though not all) scholars, Christian and non-Christian, scientist and non-scientist, accepted dualism, the view that human beings are composed of minds and bodies, two types of substance that are fundamentally distinct. Bodies were understood to be living objects composed of material parts, extended in space, subject to the laws of nature, and incapable of deliberation, reason, and thought. Minds or souls, on the other hand, were taken to be immaterial, partless entities that are capable of rational reflection, deliberation and free choice. As experimental psychology and neuroscience has progressed over the last hundred years, most scientists in these fields have come to think that there is no need to hypothesize these two distinct types of substances; instead they think that every aspect of human life, physical and mental, can be explained in terms of the workings of bodily stuff. Indeed in psychology and neuroscience, describing a theoretical position as “dualist” is often a term of derision. What has led to this radical shift?

In large part the shift can be explained because research has shown what seems to be a remarkably close correlation between the activity of the brain and the activity of the mind. Many of us are familiar with pictorial representations of the human brain, which map various mental activities onto various parts of the cerebral cortex. Neuroscientists are quick to report that we now know where (in the brain) memory, visual perception, moral reasoning, emotion, linguistic processing, and other aspects of human mental life “go on.” Because of these correlations, we can reliably cause certain kinds of mental states in human minds by electrically, chemically, or magnetically stimulating certain parts of the brain (in fact, the neuroscientist Michael Persinger claims to have developed a magnetic “helmet” capable of inducing “religious experiences”—it is in fact available for sale on the internet—though sold out the last time I checked!). What is more, we can reliably predict which kinds of mental abilities will be impaired or extinguished in cases of brain injury simply by knowing which parts of the brain have been destroyed. These clear and striking correlations between brain activity and “mind activity” have led many to conclude that there is nothing more for an immaterial soul to do. Mental activity seems to be constituted entirely by brain activity.

Are these neuroscientists right? Perhaps. But the evidence in favor of their view is not as one-sided as the near scientific consensus would make one think. In fact, there are two main sorts of problems with the reasoning that has led scientists to this consensus. First, it is not at all clear that the correlations between mental activity and brain activity signal the identity of the two. Perhaps the problem can be illustrated as follows. Imagine that life on earth is destroyed. Shortly thereafter (very shortly), aliens descend on the planet. A pair of aliens stumble into an older home and find an old-fashioned antenna-equipped broadcast television set (on which there happens to be playing old reruns of the I Love Lucy show). Never having seen such a device, the pair decides to figure out “how it works.” They remove the back of the set and one alien stands in back fiddling with wires and electronic components while the other watches from the front to see the effects. After some time (and perhaps a few jolting electrical shocks) they notice that disconnecting the red wire causes the blue color to disappear from the screen. Disconnecting the green wire causes the bass sounds to cease emanating from the speaker. Etc. After a while, they have noticed a perfect correlation between the activity (and disruption) of certain circuits in the set, and the picture and sound that the set produces. Their conclusion: working the television set is to be explained entirely in terms of the activity of the electrical components within the set.

WRONG! What the aliens did not realize (and perhaps could not realize given their experiments) was that the television also required the activity of the television station that was broadcasting the program signal. Without that, there would have been no I Love Lucy show for them to disrupt with their electrical shenanigans.

Perhaps minds and brains are related to each other in ways that are similar to the relationship between television stations and television sets. However, while this analogy is instructive, it is going to be far less than perfect. For one thing, if minds are distinct from brains, the lines of communication run both ways (unlike the television station and the set). But what this example shows is that merely finding strong correlations between neural activity and the “picture and sound” that constitutes our mental life is not enough to show their identity.

Second, there are a number of philosophical (as opposed to strictly scientific) problems with “physicalism” (the view that the mind is nothing more than the material brain) that might give us powerful reason to reject it (though the reasons won’t be scientific). First, we are all generally committed to the idea that human beings are capable of free choice. By free choice we typically mean the ability to choose between alternative courses of action in ways that are not determined by the mere workings of the laws of nature. Typically, we think that actions that are determined by the laws of nature are unfree, beyond “our control,” and thus not worthy of either praise or blame (“You can’t blame her for breaking the vase, she was sleepwalking.”). Thus, free and responsible actions are actions we undertake in virtue of choices we make that are not determined by the laws of nature. And this seems to be a problem for the physicalist. Why? Because if minds are nothing more than brains, and brains are nothing more than physical objects, and physical objects are governed by the laws of nature, there just cannot be any such thing as free choice. The reality of free choice seems incompatible with physicalism.

Here is a second problem. We are all confident that we endure through time. Once upon a time all of you reading this weighed less than twenty pounds, could not speak, and had to be fed. Not any longer. How did we pull off this trick of enduring through time, and through so very many changes (in size, weight, dexterity, and self-maintenance)? To answer this question we first need to answer the question: What does it mean for me to be “the same thing or person” that I was back then? Well, surely it does not mean that I am a thing with the same properties. So what is it that is the same? Perhaps it is that my parts endure. Perhaps. But unfortunately, as a matter of fact, they don’t. The human body is constantly undergoing repair and renewal to such an extent that we undergo a complete turnover in (molecular) parts every seven years (on average). So it looks like my enduring through time is not going to be explained by all or even some of my parts enduring.

What other options are there? There are, it seems, only two. Either I endure because some property or characteristic that is distinctive of me endures, or my endurance is explained by something quite distinct from anything material. What about the first option? The problem with the first option is that it seems, in principle, possible to duplicate the property that is “uniquely you” in another human body. Let’s say you think the distinctive property is your memory or your personality. I am writing this response on an airplane. So let’s imagine that my personality or memory is perfectly duplicated in the fellow sitting next to me right now. Question: where am I sitting? Unfortunately, every possible answer to that question is unsatisfying (I leave it to the reader to puzzle out the answers and see why). The result: this cannot be the right way to think about endurance.

The upshot of all this is that many philosophers conclude that endurance only makes sense if each of us is an entity without any parts that exists across times and is associated with our bodies, i.e., if we are a soul.

So much for some of the difficulties with physicalism. Let’s now turn to the second part of that first question (1b above). If it turns out that the scientific consensus is correct, and that, despite these problems, our minds are just our brains, does this fact clearly and directly conflict with what Scripture teaches about the nature of human beings? The answer is: not obviously. While it is true that Christian theologians have largely favored dualism through the ages, there is no small amount of evidence favoring physicalism. Consider, for example, the following passages that concern our origin and our ultimate destiny:

Taken at face value, these passages seem to indicate that we are made of material constituents (“dust”) that God has brought to life, and that when we experience physical death, we will be extinguished and without hope unless our bodies are brought back to life in a bodily resurrection. All of that makes perfectly good sense on physicalism. However, those passages require a strained reading on dualism.

I don’t mean to imply that the biblical case for physicalism is a slam dunk. Far from it. There are, for example, passages in which it appears that the spirits of dead human people are able to “appear” (Samuel, Moses, and Elijah all seem to make such appearances for example). But Christians need to be cautious in drawing philosophical conclusions about the nature of human mentality from the pages of Scripture. The fact is that the evidence is ambiguous.

Now let’s turn to question (2). Does recent psychology and neuroscience show us that belief in God is the result of a purely natural psychological process? The answer to that question is: “it depends.” Evolutionary and cognitive psychologists have recently developed a number of different naturalistic explanations of religion. These explanations aim to show that human beings are naturally disposed towards religious belief and ritual because of certain innate or native “mental tools.” Some theorists go on to argue that we have these mental tools because they, or the religion that they spawn, is and/or was adaptive for our ancestors, and were thus passed down to us.

What sort of evidence is there for such a claim? The answer to that question depends on which of the six major models of explanation one adopts. The most popular model (which we can call the “cognitive model”) contends that human beings have specific and identifiable mental tools that make religious belief easy and natural. For example, we have a mental tool that makes us think there are agents around when we detect certain sounds, motions, or configurations in nature. This “agency detector” leads us to hypothesize agents that, for example, control the forces of nature. In addition, our minds are naturally disposed to remember and transmit ideas that violate certain innate expectations we have about the workings of the world. For example, we are born (they claim) thinking that agents are physical things. When we (using the agency detection tool) are led to hypothesize agents causing the lightning or the wind, we are led to think that there are invisible agents. But invisible agents are counter-intuitive and strange. As a result, we easily remember them and talk about them, thus making such concepts spread rapidly (and thus religion is likely to spread rapidly). In addition, there is very strong evidence that we are naturally disposed, from an early age, to see goal-directedness in everything, including the natural world. This tendency has come to be called “intuitive theism” by developmental psychologists, since it is a tendency to see purposiveness throughout our world. This naturally disposes us to believe in a purpose-giving force in the universe: gods or a God.

There is a great deal of additional evidence of this sort, all of which makes it seem that religion is a natural product of the mental tools of a properly functioning human mind. But doesn’t this show that religion is just a trick that our minds play on us? Not exactly. It looks as if someone drawing this conclusion must be arguing as follows:

However, this argument commits a well known logical fallacy called the “genetic fallacy.” Genetically fallacious reasoning aims to argue for the truth or falsity of a belief simply from considerations of the origin of belief. But, of course, perfectly true beliefs can emerge even from crazy sources. I might think there are 449 people in the library because my watch reads 4:49. Can we conclude that this belief is false as a result of my strange reasoning? Of course not. It may be true, despite the strange origin.

Still, we can modify the above argument in such a way that it does not commit the fallacy but still seems to raise trouble for religious belief, as follows:

Just as my belief that there are 449 people in the library on the basis of reading my watch would be unwarranted, perhaps believing in the existence of God based on the workings of the identified mental tools would be unwarranted.

But would it be? Let’s look at the argument again, taking out the underlined word “gods” and replacing it with any of the following: human minds, rocks, rainbows, the past, that science can discover the truth, etc. Surely the conclusion of the argument in each case seems wrong. Human minds naturally form beliefs in those things and in doing so, we think, they get things right. So why not conclude that they get things right when it comes to belief in God? What makes this case different? One could say: “Well, because religious belief is false.” But that is not much of an argument—it just begs the question.

Perhaps the problem raised by these accounts is something different altogether. We might put the worry this way. In the case of our natural disposition to believe in rocks or human minds, the beliefs we formed are caused by rocks and human minds acting directly on our minds (through our senses, for example). But in the case of religious belief, belief in God arises from our “agency detector” firing off in the presence of the wind and the waves. That makes these religious beliefs very different. Rock beliefs are caused by rocks, while God beliefs are caused by . . . the wind. So, one might say, we would believe in God, even if there were no God there. And that is a problem.

This critic is right—that would be a problem. But it is not clear that what the critic is saying is true. Is it true that:

I don’t think so. I don’t think there would be a universe if there were no God. I don’t think the universe would be fine-tuned for life if there were no God. And I don’t think there would be any actual life, believers, human beings, or religion either if there were no God. Am I wrong? If I am, nothing about evolutionary or cognitive psychology indicates that I am. So, contrary to our initial conclusion, evolutionary accounts do not teach us that we would have religious beliefs whether or not they are true. As a result, this argument fails.

Perhaps there are other reasons to think that these psychological accounts raise problems for religious belief but it is not at all clear what those reasons would be. For the moment, it seems perfectly acceptable for the Christian to hold that God created the world, human beings, and human minds in such a way that when they are functioning properly, they form beliefs in the existence of rocks, rainbows, human minds, and . . . God.