Tag Archives: Substance Dualism

Video: William Lane Craig and Peter Millican debate “Does God Exist?”

From Justin Brierley and the Reasonable Faith UK Tour:

The debate was held at the University of Birmingham, England in 2011. I would put this debate in the top 3 Craig debates ever, along with his debates against Austin Dacey and Walter Sinnott-Armstrong.

My summary of the Craig-Millican is below. This debate is really meant for advanced students, but if you read my post “What you need to know about the BVG Theorem” before watching the debate, it should help you to follow along.

Dr. Craig’s opening speech:

There are good reasons to believe that God exists.

There are no good reasons to believe that God does not exist.

A1) The origin of the universe

  1. The universe began to exist
  2. If the universe began to exist, then the universe has a transcendent cause.
  3. The universe has a transcendent cause.

The origin of the universe is confirmed by philosophical arguments and scientific evidence.

There cannot be an actual infinite number of past events, because mathematical operations like subtraction and division cannot be applied to actual infinities.

The Borde-Guth-Vilenkin (BGV) proof shows that every universe that expands must have a space-time boundary in the past. That means that no expanding universe, no matter what the model, cannot be eternal into the past.

Even speculative alternative cosmologies do not escape the need for a beginning.

The cause of the universe must be transcendent and supernatural. It must be uncaused, because there cannot be an infinite regress of causes. It must be eternal, because it created time. It must be non-physical, because it created space. There are only two possibilities for such a cause. It could be an abstract object or an agent. Abstract objects cannot cause effects. Therefore, the cause is an agent.

A2) The fine-tuning of the universe

  1. The fine-tuning of the universe is either due to law, chance or design.
  2. It is not due to law or chance.
  3. Therefore, it is due to design.

The progress of science has revealed that the Big Bang was fine-tuned to allow for the existence of intelligent life.

Type 1: Constants like the gravitational constant are finely-tuned, and are not dependent on the laws of physics.

Type 2: Quantities like the amount of entropy in the universe, are not dependent on the laws of physics.

The range of life-permitting values is incredibly small compared to the possible values of the constants and quantities. (Like having a lottery with a million black balls and one white ball, and you pick the white ball. Even though each individual ball has the same tiny chance of being picked, but the odds are overwhelming that the whichever ball you pick will be black, and not white).

Not only are the numbers not due to laws, but they are not due to chance either. It’s not just that the settings are unlikely, it’s that they are unlikely and they conform to an independent pattern – namely, the ability to support complex life.

A3) The moral argument

  1. If God does not exist, then objective moral values do not exist.
  2. Objective morality does exist.
  3. Therefore, God exists.

Objective moral values are values that exist independently of whether any humans believe them or not.

Michael Ruse, an atheist philosopher agrees that if God does not exist, then there is only a “herd morality” that is determined by biological evolution and social evolution. There no objective moral standard, just different customs and conventions that vary by time and place. Anyone who acts against the herd morality is merely being unfashionable and unconventional. On the atheistic view, there is nothing objective and binding about this evolved “herd morality”. However, people do experience objective moral values, and these cannot be grounded on atheism.

Furthermore, God must exist in order to argue that there is evil in the world. In order to be able to make a distinction between good and evil that is objective, there has to be a God to determine a standard of good and evil that is binding regardless of the varying customs and conventions of different people groups. Even when a person argues against God’s existence by pointing to the “evil” in the world, they must assume objective moral values, and a God who grounds those objective moral values.

A4) The resurrection of Jesus.

  1. There are certain minimal facts that are admitted by the majority of historians, across the ideological spectrum: the empty tomb, the appearances and the early belief in the resurrection.
  2. Naturalistic attempts to explain these minimal facts fail.
  3. The best explanation of these facts is that Jesus rose from the dead.

A5) Religious experience

People can know that God exists through experience. In the absence of defeaters for these experiences, these experiences constitute evidence for God’s existence.

Dr. Millican’s opening speech:

Dr. Craig has the burden of proof because he claims that God exists.

The Christian God hypothesis:

  1. An omnipotent, omniscient, omnibenevolent God created the universe.
  2. This God cares about humans.
  3. This God has acted in history though the life of Jesus of Nazareth.

This is a factual claim, and we are discussing the evidence for whether these claims are true or false. We are not interested in religious practice, or the consolation of religious belief, nor any other religions.

A1) Religious pluralism and epistemology

Human beings are purpose-finding creatures – we are prone to prefer explanations that involve purpose.

Human beings are pattern-finding animals – we tend to find designs in states of affairs.

Human beings have an interest in maintaining religious hierarchies because of the power it gives them.

Religious beliefs are not determined by rational considerations, but are determined by geographic location.

The same non-scientific method of generating religious beliefs (purpose-finding, pattern-finding, geographic location, parental teaching, charismatic speakers, praise songs and worship, religious education, ancient holy books) is being used in several religions, and it leads to different, contradictory truth claims. So at least some of those conflicting claims are false. And if the method is generating some false claims, then it’s not a good method, and it undermines all the religions that use those methods.

A2) Absence of evidence is evidence of absence

There is no scientific evidence for God.

A3) Mental processes depend on physical systems

There is no scientific evidence for a disembodied intelligence.

Our universal human experience is that intelligence and mental operations require a physical brain.

The quality of our thinking depends on physical conditions, like being tired or on drugs.

But Christian theists believe that mental processes can exist independently of an underlying physical reality, unimpaired by the death of the physical body and the brain.

R.A1) The origin of the universe

1. There is no evidence that whatever begins to exist requires a cause. All the evidence we have of things beginning to exist are when something is created from rearrangements of other things that already existed.

The closest analog we have to something coming into being from nothing is quantum particles coming into being from nothing, and that causation is random.

There is no evidence that thoughts can bring about physical effects, and Bill is arguing for a mental cause to the origin of the universe.

Even if things that begin to exist IN the universe have causes, it doesn’t hold for the universe as a whole. Bill is committing the fallacy of composition.

Time begins with the universe, but our experience of causation is that it is a temporal process. So if there is no time “prior to” the universe’s beginning, then how can there be a cause to the universe?

It’s possible that there could be something outside our universe that is eternal.

It’s also possible that the Big Bang could be wrong, and this universe could oscillate eternally and not require a beginning.

2. There are cosmological theories that avoid the beginning of the universe by positing a prior period of contraction prior to the Big Bang.

The beginning of this universe depends on general relativity, and that theory breaks down at the level of quantum mechanics.

3. There is no evidence that minds can exist without an underlying physical system. So even if there is a cause of the universe, then it is neither an abstract object nor a mind. It would have to be something else, and not something we are familiar with – we are just not in a position to speculate of what it could be.

R.A3) The moral argument

Atheists do believe in a standard of morality that is not based on what groups of humans believe.

Utilitarians think there is a standard of moral values that is objective, because the measure of human happiness (for the greatest number) is objective, even if people are mistaken about what promotes that happiness.

Kantians have a rational process for determining which moral imperatives should be universalized.

Humeans have a system that is rooted in natural human sentiment.

Dr. Craig’s first rebuttal:

I do not have the only burden of proof. The topic is “Does God Exist?”. If Dr. Millican answers “no” then he has a burden of proof, otherwise we are left with agnosticism.

R.A1) Religious pluralism and epistemology

First, there is no single common method of adopting a religion.

Second, MY method this evening is logic and evidence and personal experience – which is the same as his method. So his comments about how people in different religions adopt their religion through parents, church, singing, etc. have no bearing on the arguments I will be making.

R.A2) Absence of evidence is evidence of absence

Absence of evidence is only evidence of absence if we can reasonably expect that there should be some evidence that is not present. He would have to show that there should be more evidence for God’s existence that the 5 arguments that I already presented – something that we should expect to see that we don’t see.

R.A3) Mental processes depend on physical systems

No response by Dr. Craig. (but see below)

A1) The origin of the universe

1. He says that there are speculative cosmologies like the multiverse that escape the need for a beginning, but that’s false, the BGV proof applies to them, and they do need a beginning.

He says that you can escape BGV by positing a contraction prior to the expansion. However Vilenkin says that any contraction phase is unstable and would introduce additional singularities that would hamper any later expansion phase.

He  says that we need a theory of quantum gravity in order to describe the early universe. But Vilenkin says that the BGV proof is independent of gravity as defined by general relativity.

He did not respond to the philosophical arguments for a beginning of the universe.

2. He says that we don’t have experience of things coming into being except from material causes. However, it would be even more difficult to explain the universe coming into being on atheism since you can’t appeal to a material cause nor to an efficient cause. Even Hume recognizes that things can’t pop into being without causes.

He talks about how in quantum physics virtual particles appear out of nothing. But that’s false, because the quantum vacuum in which virtual particles appear is not nothing, it is a sea of subatomic particles and energy. Quantum physics is not an exception to the idea that things that come into being require a cause.

He mentions the fallacy of composition. But I am not saying that everything in the universe has a cause, therefore the universe as a whole has a cause. I am saying that non-being has no capacity to bring something into being. Non-Being doesn’t even have the potential to bring something into being.

3. He says that there are no unembodied minds, so the cause of the universe can’t be an unembodied mind. But the argument concludes that there is a non-material cause, and it can’t be an abstract object, so it would have to be a mind.

In addition, we ourselves are unembodied minds.  This is because physical objects cannot have the properties that minds have, like the property of having feelings.

Material conceptions of mind don’t explain identity over time.

Material conceptions of mind don’t explain free will.

Material conceptions of mind don’t explain intentional states (thinking about something).

Material conceptions of mind don’t explain mental causation.

The best explanation for our own first person experience of the mental realm is a substance dualism. We are non-material minds, and we can cause effects in the physical world. And God does the same thing. He is a mind, and he causes physical effects.

A2) He gave no response.

A3) He says that there are atheistic theories of morality that don’t depend on the opinions of groups. But these theories all depend on the idea that human beings have instrinsic value – that they are the sorts of things to which moral considerations apply. Naturalism cannot ground this moral value – human beings are no more valuable any other animal.

Also, there are no objective moral obligations in naturalist systems of morality, because there is no one in authority to command them. Moral prescriptions require moral prescribers.

A4) He gave no response.

A5) He gave no response.

Dr. Millican’s first rebuttal:

R.A2) The fine-tuning argument

We have to be careful not to judge what counts as finely-tuned through our intuitions.

We have to be careful about reasoning for a sample size of this one observable universe.

We don’t really know about the full range of possibilities for these constants and quantities.

There might be other universes that we can’t observe that aren’t fine-tuned, and we just happen to be in the one that is fine-tuned.

The fine-tuning might be solved by future discoveries, like the inflationary cosmology removed some of the fine-tuning.

There might be a multiverse that we don’t have evidence for right now.

We need to be careful about using science to prove God because science might change in the future.

The universe is very big and mysterious.

This argument doesn’t prove that God is good. He could be evil = anti-God.

God created the universe inefficiently if his goal was to produce life.

God created the universe too big.

God created the universe too old.

God created too many galaxies and stars that are not hospitable to life.

If the universe were fine-tuned for life, then there should be more aliens.

If the universe were fine-tuned for life, then there are probably lots of alien civilizations. But then Jesus would have to appear to all of the aliens too.

R.A1) The origin of the universe

2. It’s not a big deal that you can get multiple solutions to equations involving subtraction of actual infinities. For example, the equation 0 x y = 0 has many solutions for y, but that doesn’t mean that multiplication doesn’t work in the real world.

A2) Absence of evidence is evidence of absence

I would expect that there would be more evidence than there is.

R.A1) The origin of the universe

2. The BVG proof might be overturned by future scientific discoveries. We have no reason to be confident in current physics.

I agree that the quantum vacuum is something and not nothing, but it’s similar to nothing.

We don’t have any reason to believe that things that come into being require causes – except for our universal experience that this is always the case.

3. As to the cause of the universe coming into being, you said that it could only be an abstract object or a mind, and it can’t be an abstract object because they don’t cause effects, so it must be a mind. But there are all sorts of things we’ve never thought of that it could be other than a mind.

I agree that mental properties are not physical properties and that epiphenomenalism is incorrect. Physical objects can have “algorithmic properties” as well as physical properties, it doesn’t mean that computers have minds.

Dr. Craig’s second rebuttal:

R.A2) Absence of evidence is evidence of absence

He expressed his personal opinion that there should be more evidence, but that’s not an argument.

God knows how people will respond to getting more evidence or less evidence and he has to be careful not to take away their free will to disbelieve by piling them up with coercive evidence. God’s goal is not just to convince people that he exists. God’s goal is to have people respond to him and pursue him.

A1) The origin of the universe

2. He said that multiple answers to equations are no problem. But the problem is that you can’t translate multiple answers into a real world context.

The problem is that you are subtracting an identical number from an identical number and getting contradictory results, and that cannot be translated into the real world, where subtraction always gives a definite single result.

He talks about how you can get multiple answers with multiplication by 0. But 0 is not a real quantity, it is just the absence of something, and that cannot translate into the real world, because it has no being.

He says that I am only using evidence from current physics. But that is the point – the evidence of current physics and cosmology supports the beginning of the universe.

3. He said that an umembodied mind can’t be the cause, but we are minds and we cause effects on our physical bodies.

In addition, the design argument supports the idea that the cause of the universe is intelligent.

A2) The fine-tuning of the universe

He says we should be cautious. Of course.

He says the probabilities can’t be assessed. But you can just take the current value and perturb it and see that the resulting universe loses its ability to support life, and you can test an entire range around the current value to see that that vast majority of values in the range don’t permit life.

He says that the current physics is not well-established, but there are so many examples of fine-tuning across so many different areas of science that it is not likely that all of them will be overturned, and the number of finely-tuned constants and quantities has been growing, not shrinking.

He says it doesn’t prove that God is good, and he’s right – that’s what the moral argument is for.

He says that God isn’t efficient enough, but efficiency is only important for those who have limited time and/or limited resources. But God has unlimited time and resources.

He says that the universe is too old, but the large age of the universe is a requirement to support intelligent life – (i.e. – you need third generation stars to provide a stable source of energy to planets, and those stars require that two generations of stars are born and die).

He said what about aliens, and theists are open to that, and God can certainly provide for the salvation of those beings, if they have fallen into sin.

Dr. Millican’s second rebuttal:

R.A1) The origin of the universe

3. Just because epiphenominalism is false, it doesn’t mean that substance dualism is true.

The majority of philosophers of mind do not accept substance dualism.

R.A3) The moral argument

The majority of philosophers are moral realists, but a minority of philosophers are theists. So that means that there must be some way of justifying morality on atheism, which I will not describe right now.

Atheists can express their opinion that humans have intrinsic moral value.

He grants that atheists can perceive moral values. But if atheists can perceive moral values, then why is God needed to enable that?

Atheists can express their opinion that humans are special. We can be rational, and that makes us special.

Atheists can express their opinion that it is good to care about other humans because they are of the same species.

R.A4) The resurrection of Jesus

We don’t have any reasons to believe i the supernatural.

The gospels are written late for the purposes of evangelism.

The gospels are not independent, e.g. Matthew and Luke depend on Q.

John is the latest gospel, and the Christology of John is the highest of all.

The four gospels agree because the early church rejected other (unnamed) gospels that didn’t agree.

Matthew 27 – the earthquake and the raised saints – is not recorded in any other contemporary non-Christian source.

Dr. Craig’s final rebuttal:

A3) The moral argument

He says that human beings are rational, and that gives them value. But atheists like Sam Harris prefer the flourishing of sentient life. He includes non-rational animals as having moral value. So without God, we see that the choice of who or what has moral value is arbitrary. And where would objective moral duties come from if there is no moral lawgiver?

The fact that most atheists accept objective moral values doesn’t mean that they can rationally ground those values on their atheistic worldview. You can’t provide a basis for moral values on atheism by counting the number of atheists who accept objective morality. It’s not surprising that atheists can perceive objective moral values IF they are living in auniverse created by God who grounds these objective moral values and duties that atheists perceive.

A4) The resurrection of Jesus

He cites Geza Vermes and Bart Ehrman as authorities on the historical Jesus, but both of them accept all three of the facts that I presented as minimal facts. Ehrman doesn’t accept the resurrection of Jesus because he presupposes naturalism. He rejects the resurrection on philosophical grounds, not historical grounds.

Dr. Millican’s final rebuttal:

R.A5) Religious experience

Religious experience is an unreliable way to test the claims of a religion, because lots of religions have them and they make contradictory truth claims. In the future, we may discover naturalistic ways of explaining religious experience.

R.A4) The resurrection of Jesus

Even if you can make a case for the resurrection based on these3  minimal facts, there are other stories in the New Testament like Matthew 27 that are quite weird and they undermine the 3 minimal facts that even Geza Vermes and Bart Ehrman accept.

R.A1) The origin of the universe

Bill hasn’t shown that there is any reason for thinking that things don’t come into being, uncaused, out of nothing.

A4) The problem of evil

Theists can’t explain what God’s specific morally sufficient reasons are for permitting the apparently gratuitous evil that we see.

EEG device detects consciousness in persons in persistent vegetative state

Here’s an interesting article from the New Scientist.

Excerpt:

Signs of consciousness have been detected in three people previously thought to be in a vegetative state, with the help of a cheap, portable device that can be used at the bedside.

“There’s a man here who technically meets all the internationally agreed criteria for being in a vegetative state, yet he can generate 200 responses [to direct commands] with his brain,” says Adrian Owen of the University of Western Ontario. “Clearly this guy is not in a true vegetative state. He’s probably as conscious as you or I are.”

[Owen’s team] devised a test that uses the relatively inexpensive and widely available electroencephalogram (EEG).

An EEG uses electrodes attached to the scalp to record electrical activity in the brain.

Owen and his team used an EEG on 16 people thought to be in a PVS and compared the results with 12 healthy controls while they were asked to imagine performing a series of tasks.

Each person was asked to imagine at least four separate actions – either clenching their right fist or wiggling their toes.

In three of the people with PVS, brain regions known to be associated with those tasks lit up with activity, despite physical unresponsiveness. This suggested to the researchers that the subjects were carrying out a complex set of cognitive functions including hearing the command, understanding language, sustaining attention and tapping into working memory.

“It isn’t the case that just because somebody doesn’t respond they’re not conscious,” Owen says. “There’s a growing body of data now demonstrating that many of these patients aren’t what they appear.”

The rest of the article talks about how the scientists are planning to use their new technique to communicate with patients by asking them to think of specific things which will mean “yes” or “no”. The long-term goal is to get the patients to be able to communicate, perhaps even allow them to move a mouse pointer by triggering reactions in their brains by using their thoughts.

I think this research dovetails nicely with the OCD research I mentioned before. Maybe now would be a good time to talk more about that research.

William Dembski discusses the OCD research of Jeffrey Schwartz.

Excerpt:

Schwartz provides a nonmaterialist interpretation of neuroscience and argues that this interpretation is more compelling than the standard materialist interpretation. He arrived at this position as a psychiatrist specializing in the treatment of obsessive-compulsive disorder (OCD). OCD sufferers recognize obsessive-compulsive thoughts and urges as separate from their intrinsic selves. For instance, after a few washings, the compulsive hand-washer realizes that his hands are clean and yet feels driven to keep washing them. It was reflection on this difference between the obvious truth (the hands are clean) and the irrational doubts (they might still be dirty) that prompted Schwartz to reassess the philosophical underpinnings of neuroscience.

From brain scans, Schwartz found that certain regions in the brain of OCD patients (the caudate nucleus in particular) exhibited abnormal patterns of activity. By itself this finding is consistent with a materialist view of mind (if, as materialism requires, the brain enables the mind, then abnormal patterns of brain activity are likely to be correlated with dysfunctional mental states). Nonetheless, having found abnormal patterns of brain activity, Schwartz then had OCD patients engage in intensive mental effort through what he called relabeling, reattributing, refocusing, and revaluing (the 4 Rs). In the case of compulsive hand-washing, this involved a patient acknowledging that his hands were in fact clean (relabeling); attributing anxieties and doubts about his hands being dirty to a misfunctioning brain (reattributing); directing his thoughts and actions away from handwashing and toward productive ends (refocusing); and, lastly, understanding at a deep level the senselessness of OCD messages (revaluing).

Schwartz documents not only that patients who undertook this therapy experienced considerable relief from OCD symptoms, but also that their brain scans indicated a lasting realignment of brain-activity patterns. Thus, without any intervention directly affecting their brains, OCD patients were able to reorganize their brains by intentionally modifying their thoughts and behaviors. The important point for Schwartz here is not simply that modified thoughts and behaviors permanently altered patterns of brain activity, but that such modifications resulted from, as he calls it, “mindful attention”-conscious and purposive thoughts or actions in which the agent adopts the stance of a detached observer.

It turns out that people can freely choose to exert “mental effort” in order to change what their brains are doing.

By the way, if you like this topic, and want a resource to show your friends, be sure and get a hold of the debate on mind vs. brain between Jeffrey M. Schwartz and Michael Shermer.

Some arguments for substance dualism, and one objection

Philosophy of mind is not something I’ve studied very much, but I do know about the different views like physicalism, epiphenomenalism, property dualism and substance dualism. I also know some of the basic arguments for and against each view.

In this post, I just wanted to show people a little bit about how you argue for substance dualism, using philosophical and scientific arguments. I find this topic to be really really dry, and I can barely stay awake when J.P. Moreland talks about it in lectures. But I hope a little bit of exposure won’t put you all to sleep.

Philosophical arguments

Let’s start with this old paper by John Depoe.

He writes about the persistent identity argument:

Another argument supporting substance dualism is that one maintains personal identity through change. Even though one is continuously going through physical changes and experiencing different mental states, a person continues to be the same person. If persons were identical with their physical parts or mental states, they would cease to be the same persons as these changes occurred. Therefore, it is necessary to postulate an immaterial, substantial self that endures through change.

Suppose that someone believes that people do not maintain identity through change and concludes that the previous argument for substance dualism fails. This denial of personal identity through change, I contend, presents untenable difficulties. First, there is one’s own awareness of being the same person through change. Moreover, if one is not literally the same person through these changes, how can a person maintain long-term goals and desires?

If you are your body, and your body is always changing, then you aren’t the same person now as 5 minutes ago.

There are more arguments for substance dualism here, from J.P. Moreland.

Experimental evidence

Doug Groothuis talks about some experimental evidence in this paper.

Excerpt:

Dr. Wilder Penfield was known for his ground-breaking work with epilepsy. His work involved stimulating brain tissue in conscious patients in order to find the causes of epilepsy. During these sessions Penfield found that the prodding of certain areas of the brain triggered vivid memories of past events. The patients reported remembering clearly such things as the taste of coffee. One patient, while on an operating table in Montreal, Canada, remembered laughing with cousins on a farm in South Africa. What amazed Penfield was that his patients, who were not under anesthetic, were simultaneously conscious of the re-experienced memories and of being prodded by an electrode in an operating room. Penfield called this a “double consciousness” wherein a memory was stimulated physically but was attended to and recognized as a memory by a conscious patient. Penfield likened this to the patient watching a television program while remaining aware that it wasn’t now happening.

Penfield repeated these results on hundreds of epileptic patients and concluded that a separable mind was able to track what the brain was doing as a result of the artificial stimulation. One’s mind in a sense could transcend the operations of the brain, monitoring memories without actually placing oneself in the situation remembered. Penfield noted that “The mind of the patient was as independent of the reflex action as was the mind of the surgeon who listened and strove to understand. Thus, my argument favours independence of mind-action.” Penfield also stated that if we liken the brain to a computer, it is not that we are a computer, but that we have a computer.

Penfield, who began his research as a materialist, switched to dualism after extensive research with epileptic patients. He said, “Something else finds its dwelling place between the sensory complex and the motor mechanism. . . . There is a switchboard operator as well as a switchboard.”

Although nonepileptic patients do not respond similarly to brain stimulation, other researchers, such as Sir John Eccles, a neurobiologist, have similarly concluded that the brain alone cannot account for a many phenomena. Eccles’ hypothesis is that the self-conscious mind is an independent entity that is actively engaged in reading from the multitude of active centres in the modules of the liaison areas of the dominant cerebral hemisphere. The self-conscious mind selects from these centres in accord with its attention and its interests and integrates its selection to give unity of conscious experience from moment to moment.

Thus, Eccles’ conclusions agree with Penfield’s, and his areas of research extend farther than that of epileptic patients. Eccles deems the “monist materialist” hope for an eventual physical explanation for mental events as wrongheaded in principle because mental events are not “simply derivative of aspects of nerve endings. There is no evidence for this whatever.” Further, Eccles argues that his “strong dualist-interactionist hypothesis . . . has the recommendation of its great explanatory power. It gives in principle at least explanations of the whole range of problems relating to brain-mind interaction.”Eccles notes that it has been impossible to develop a materialist explanation of “how a diversity of brain events come to be synthesized so that there is a unified conscious experience of a global or gestalt character.” Given this impasse, Eccles proposed that “the self-conscious mind” serve to integrate the apparently disparate brain processes into a unified consciousness.

I think that Alvin Plantinga, Keith Yandell, J.P. Moreland, William Lane Craig, Stephen Davis, John Depoe, Douglas Groothuis and Charles Taliaferro all defend substance dualism. I’m a substance dualist, myself.

What’s the objection to substance dualism?

The big objection to substance-dualism is the problem of how you get the non-physical substance to interact with the physical substance. It’s like how people put forward the grounding objection when talking about middle knowledge and where God’s knowledge of counterfactuals of creaturely freedom comes from. I wonder if anyone can post a comment for me to point me to a resource on answering the interaction problem in the comments.

UPDATE: One of my elite special forces ninja commenters writes:

Here’s Ed Feser on the Interaction Problem:

http://edwardfeser.blogspot.com/2008/10/interaction-problem.html

and

http://edwardfeser.blogspot.com/2009/04/interaction-problem-part-ii.html

The thrust of his argument is that, if the soul is the extension of the body’s “form” without matter, then it interacts with the more material parts of us in the same way that forms in general interact with matter- this approach involves rethinking our metaphysical understanding of matter, rather than coming up with a clever idea of the soul, and it does get rather involved in Thomistic metaphysics, but I think it’s pretty interesting.