Tag Archives: Body

Polemics

Alexander Pruss answers an objection to mind-body dualism

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I found this post on the Biola University Christian Thought blog. It’s by famous philosopher Alexander Pruss. In it, he considers 3 arguments against non-physical souls.

Here is the third objection:

The third objection is based on the Closure Principle: The physical world is explanatorily closed—the explanations of physical states of affairs are always physical in nature. The closure principle would let one be confident that scientists don’t need to look for miracles—that explanations of physical events will never go beyond science. If the Closure Principle is true, then no physical event in the brain has an explanation by means of a soul.

And here is his reponse:

I’m going to argue that the Closure Principle is more likely to be false than true.

My argument has two parts. The first part will be to establish the No Physical Explanation Thesis:

No Physical Explanation Thesis: Whether or not the Closure Principle is true, some physical states of affairs have no physical explanations.

The second part will argue that if the above thesis is true, then the Closure Principle is more likely to be false than true.

Sounds to me like he is just talking about the assumption of metaphysical naturalism, which some people accept because of the success of explaining nature using natural explanations. But can you really explain everything with only natural explanations?

Let’s see:

So, first, I need to argue that some physical states of affairs have no physical explanations. A quick argument for this thesis is to consider all of physical reality as a whole. This constitutes a gigantic physical state of affairs. This gigantic physical state of affairs cannot have a physical explanation. For if it had a physical explanation, that physical explanation would be a part of the gigantic physical state of affairs, since that gigantic state contained all of physical reality. But then the explanation, in explaining that gigantic state, would also explain itself, since it itself is a part of the gigantic state. But no physical state of affairs can explain itself—that would be like the absurdity of being one’s own parent.

A second (related) argument is that if every physical state of affairs has a physical explanation, we end up with a vicious infinite regress of physical states of affairs. Physical state #1 is explained by physical state #2 (maybe, my existence is explained by my parents’ existence), which then must be explained by physical state #3, and so on. So we have an infinite regress of physical states of affairs. But the regress does not stop there. For the whole infinite regress will be a physical state of affairs, and hence will need an explanation. So we will have another regress, and another, and so on. This is really absurd.

A third argument is that current science gives us good reason to think that physical reality is not infinitely old, that it came into existence some finite amount of time ago, maybe in a Big Bang. If so, then the state of affairs of physical reality coming into existence won’t have a physical explanation.

These three arguments for the No Physical Explanation Thesis are basically adaptations of the Cosmological Argument for the existence of God, but I am not concluding from them that there is a God—just that something physical has no physical explanation.

So now we’ve learned that some physical state of affairs has no physical explanation.

Let’s give a name to some such physical state of affairs—call it “Blob.” Blob, then, has no physical explanation. There are now two possibilities. Either (1) Blob has no explanation at all, or (2) Blob has a non-physical explanation.

If Blob has a non-physical explanation, then the Closure Principle is false, since the Closure Principle said that no physical state of affairs has a non-physical explanation, and here is Blob—a physical state of affairs with a non-physical explanation.

Of the two options, which is more likely? Blob having no explanation at all? Or Blob having a non-physical explanation? I will argue that think the likelier option is the latter—that Blob has a non-physical explanation.

For physical states of affairs are contingent—they don’t have to be there. Blob, thus, doesn’t have to be there. The idea of something contingent having no explanation is like the idea of something coming into existence out of nothing. It is intuitively absurd. Much more absurd than the alternative, namely that it has a non-physical explanation. Maybe it’s hard for something physical to happen because of a non-physical cause—but it should be far harder for something physical to happen for no cause at all. If we think that that something contingent could happen for no cause at all, it should be even easier for it to happen due to a non-physical cause. So it is more likely that Blob has a non-physical explanation than that it has no explanation at all. But if it has a non-physical explanation, then the Closure Principle is false. So, most likely, the Closure Principle is false.

Moreover, if we admitted that a physical state of affairs, namely Blob, could take place for no reason at all, with no explanation, then it would be a wonder why all sorts of other physical things don’t happen for no reason at all. Why doesn’t a dog-headed person suddenly pop into existence for no cause at all in front of me? Why doesn’t a golden mountain materialize in the middle of the Pacific Ocean out of nowhere? I can give a very simple explanation of why all these infinitely many strange things don’t happen: all physical states of affairs have to have explanations. But this explanation also implies that the Closure Principle is false. For we know that Blob has no physical explanation, and so Blob’s explanation must be non-physical.

The Closure Principle was introduced in large part to save science from giving up on physical explanations and looking for supernatural ones. But if we accept the Closure Principle, then we have to say that some physical states of affairs have no explanation at all. And it is much worse to be willing to give up completelyon a search for explanation than to be willing to give up on a search for physical explanation.

We should thus think that most likely the Closure Principle is false, and hence this argument against interaction between the soul and the body fails as much as the previous ones did.

This sounds a lot like William Lane Craig’s contingency argument, and I think that it is particularly mean (to the naturalists) to invoke science to smash their naturalism. I certainly accept non-physical causation when it comes to the origin of the universe – nothing too mysterious about that. And I think he’s right to say that this shows that it’s at least possible, then, that a non-physical entity could effect material things like our bodies. In fact, I’ve heard J.P. Moreland argue that this is what God actually is – a non-physical mind.

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Can computers become conscious by increasing processing power?

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There is a very famous thought experiment from UC Berkeley philosopher John Searle that all Christian apologists should know about. And now everyone who reads the Wall Street Journal knows about it, because of this article. (H/T Sarah)

Searle is writing about the IBM computer that was programmed to play Jeopardy. His Chinese room example shows why no one should be concerned about computers acting like humans. There is no thinking computer. There never will be a thinking computer. And you cannot build up to a thinking computer my adding more hardware and software.

Excerpt:

Imagine that a person—me, for example—knows no Chinese and is locked in a room with boxes full of Chinese symbols and an instruction book written in English for manipulating the symbols. Unknown to me, the boxes are called “the database” and the instruction book is called “the program.” I am called “the computer.”

People outside the room pass in bunches of Chinese symbols that, unknown to me, are questions. I look up in the instruction book what I am supposed to do and I give back answers in Chinese symbols.

Suppose I get so good at shuffling the symbols and passing out the answers that my answers are indistinguishable from a native Chinese speaker’s. I give every indication of understanding the language despite the fact that I actually don’t understand a word of Chinese.

And if I do not, neither does any digital computer, because no computer, qua computer, has anything I do not have. It has stocks of symbols, rules for manipulating symbols, a system that allows it to rapidly transition from zeros to ones, and the ability to process inputs and outputs. That is it. There is nothing else.

By the way, Searle is a naturalist – not a theist, not a Christian. But he does oppose postmodernism. So he isn’t all bad. But let’s hear from a Christian scholar who can make more sense of this for us.

UPDATE: Drew sent me a link to the full article by Searle.

Here’s an article by Christian philosopher Jay Richards.

Excerpt:

Popular discussions of AI often suggest that if you keep increasing weak AI, at some point, you’ll get strong AI. That is, if you get enough computation, you’ll eventually get consciousness.

The reasoning goes something like this: There will be a moment at which a computer will be indistinguishable from a human intelligent agent in a blind test. At that point, we will have intelligent, conscious machines.

This does not follow. A computer may pass the Turing test, but that doesn’t mean that it will actually be a self-conscious, free agent.

The point seems obvious, but we can easily be beguiled by the way we speak of computers: We talk about computers learning, making mistakes, becoming more intelligent, and so forth. We need to remember that we are speaking metaphorically.

We can also be led astray by unexamined metaphysical assumptions. If we’re just computers made of meat, and we happened to become conscious at some point, what’s to stop computers from doing the same? That makes sense if you accept the premise—as many AI researchers do. If you don’t accept the premise, though, you don’t have to accept the conclusion.

In fact, there’s no good reason to assume that consciousness and agency emerge by accident at some threshold of speed and computational power in computers. We know by introspection that we are conscious, free beings—though we really don’t know how this works. So we naturally attribute consciousness to other humans. We also know generally what’s going on inside a computer, since we build them, and it has nothing to do with consciousness. It’s quite likely that consciousness is qualitatively different from the type of computation that we have developed in computers (as the “Chinese Room” argument, by philosopher John Searle, seems to show). Remember that, and you’ll suffer less anxiety as computers become more powerful.

Even if computer technology provides accelerating returns for the foreseeable future, it doesn’t follow that we’ll be replacing ourselves anytime soon. AI enthusiasts often make highly simplistic assumptions about human nature and biology. Rather than marveling at the ways in which computation illuminates our understanding of the microscopic biological world, many treat biological systems as nothing but clunky, soon-to-be-obsolete conglomerations of hardware and software. Fanciful speculations about uploading ourselves onto the Internet and transcending our biology rest on these simplistic assumptions. This is a common philosophical blind spot in the AI community, but it’s not a danger of AI research itself, which primarily involves programming and computers.

AI researchers often mix topics from different disciplines—biology, physics, computer science, robotics—and this causes critics to do the same. For instance, many critics worry that AI research leads inevitably to tampering with human nature. But different types of research raise different concerns. There are serious ethical questions when we’re dealing with human cloning and research that destroys human embryos. But AI research in itself does not raise these concerns. It normally involves computers, machines, and programming. While all technology raises ethical issues, we should be less worried about AI research—which has many benign applications—than research that treats human life as a means rather than an end.

Jay Richards is my all-round favorite Christian scholar. He has the Ph.D in philosophy from Princeton.

When I am playing a game on the computer, I know exactly why what I am doing is fun – I am conscious of it. But the computer has no idea what I am doing. It is just matter in motion, acting on it’s programming and the inputs I supply to it. And that’s all computers will ever do. Trust me, this is my field. I have the BS and MS in computer science, and I have studied this area. AI has applications for machine learning and search problems, but consciousness is not on the radar. You can’t get there from here.

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J.W. Wartick explains why Christians should not embrace a materialist conception of humanity

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From the blog Always Have a Reason, a case against the idea that Christians can embrace a materialist conception of humanity.

Problem 1: a concept of the self that persists through the passage of time:

He writes:

How do we maintain identity through time? Here, the problem must be answered by all materialists, not just Christian materialists.

The problem is, of course, that our bodies don’t maintain physical identity. We are continually replacing the physical parts of our body over time. Now, I am hesitant to make the oft-repeated claim that our entire bodies are replaced every so many years, as I have been unable to find any research confirming it. However, it simply is the case that large portions of our body are replaced. Given this fact, how do we maintain identity? What is it that keeps us the same person over time?

Another major problem is this: to which part of our body are we identical? Or, to put it another way, which parts of our body do we need to keep in order to be the same person? Here we can appeal to a thought experiment. A mad scientist has us captured and he wants to see how long we can maintain identity. Slowly, he replaces each part of our body with a new one with the exact same DNA, structure, etc. As he replaces these parts, he discards the old ones and destroys them. He starts with the legs. Then he moves to the midsection, replacing one organ at a time. Then the heart, the arms,  the ears, the eyes. When he gets  to the brain, he goes through and replaces only single neurons at a time.

The question is pretty obvious: When do we stop being the same person? The materialist simply has to admit that we are our bodies (for what else could we be?). But given that fact, to which part are we identical? The brain? If so, at one point in the experiment do we cease to exist? 51% of our brain is gone? 70%? All but one neuron? So is our identity grounded in that one neuron? If so, which one? Or is it just grounded in having any one neuron as the same? If so, how?

Problem 2: materialism cannot make sense of the bodily resurrection:

He writes:

Central to the Christian hope is the hope for a future resurrection. The question which must be asked is this: Is this hope grounded in reality?

Suppose materialism were true. If that is the case, then humans are identical with their bodies in some fashion. I am intentionally vague here because I admit I’m not convinced as to how identity works within a Christian view of materialism (see above). If this were the case, then when we die and our material body decomposes, it may go on to become all sorts of different things, which themselves later pass away (plants may grow from the nutrients broken down from the body; then those plants may be harvested and eaten by other humans/animals/etc, which then die and are broken down, etc.). In the resurrection, then, God creates our body anew, complete–I assume–with our memories, experiences, etc. built in (perhaps they are simply functions of our brain, which God recreated perfectly, which thus contains our experiences).

Is there actual hope on this scenario?

Suppose the mad scientist were to come and kidnap you. He gleefully announces that he is going to use you for excruciatingly painful experiments which will take place over several years until you die. But, do not worry, because once you die, he is going to create a new body which is an exactly perfect copy of you, which will of course have all your experiences (minus this torturous one) and memories in place, and then he is going to give you billions of dollars.* Would you be comforted by this scenario? After all, you’re not going to remember the pain and you are going to come out the other end extremely rich!

Well there is a problem: the new body is not you. It is just a copy. For any materialist, this is problematic. We seem to know that identity transcends the body. But let us not delve into that difficulty right now. Instead, we will focus on Christian materialism. Now, it seems to me that this problem is almost the same for the Christian materialist with the Resurrection. After all, we are going to die. But we are told, don’t worry, we will be raised bodily by God! But whose body is going to be raised? How will God gather the material from our body (and at which time of our body–see above) in order to recreate us? And will not this body purely be a copy, rather than actually us?

There is a real disconnect here. Christian materialism cannot offer us the hope of the resurrection, without which our faith is worthless (1 Corinthians 15). Instead, it offers us the hope for our future copies, which will themselves have our memories and experiences, but will not be us. Our bodies will die and distribute throughout various portions of the world (even the universe–who knows if an asteroid might hit and distribute the molecules which made up our body elsewhere?). Then God will create us again in some fashion, and that body will live on in the Kingdom. But that body is not us. It will be a new body. This isn’t begging the question, it is merely stating a fact. The body that will be raised is not the body I have now. Thus, if I am my body, I am not raised.

And I would add to that additional problems with generic materialism, like first-person consciousness, freedom of the will, rationality, and so on. It’s just not a sound view.

I remember attending a philosophy of religion conference at Wheaton College a long time back, where the main speaker was Christian materialist Peter Van Inwagen. Both of these objections were raised against him, and neither objection was adequately responded to, in my opinion. In contrast, the orthodox view (body and soul dualism) holds up very well. The biggest problem with the dualist view (my view) is how do the body and soul/mind interact. But I think that problem is much smaller than the problems that J.W. raised above.