Hi all,
My name is Casper, I'm new here. I'm a neuroscientist and an astrophysicist, at the same time :). I'll try to keep it short because there's so much to say on this topic. (edit: Wow I sure didn't succeed in keeping it short!)

I personally find the perspective of emergentism / dynamicism to be very fruitful when thinking about the relationship between consciousness and the brain. It helps to step beyond the whole physicalism-dualism dichotomy. It can be summarized by the statement of Gestalt psychologist Kurt Koffka: "The whole is other than the sum of its parts." I always come back to that one because its implications are so profound. Taken seriously, it implies that consciousness can be something fundamentally different from the brain, yet still emergent from it. Also, consciousness as a higher order phenomenon can act indirectly on neural processes by constraining the possible outcomes.

Soul is describing something altogether different (although not separate) from consciousness. The soul is the life of a person. I think the life of a person can never be separated from the body because we need our bodies to have human life in any meaningful sense. This is also why the bodily resurrection is so crucial to the Gospel. So what happens between our death and the Second Coming? Well I suppose we sort of exit time and pass into the Kingdom immediately. Jesus said to the criminal next to him on the cross, "Truly, I tell you, today you will be with me in Paradise."

I don't know whether Sarah Lane Ritchie is still following this thread, but I would like to respond to something she said in her first post here:

I find nonreductive physicalism to be unsatisfying instance of wanting to "have one's cake and eat it too." That is, nonreductive physicalists want the credibility that often comes with calling yourself a physicalist - it's an academically respectable position.

I think this is not a fair accusation to make if the science is strongly indicating a physical origin of consciousness (which is indeed the case if you ask any neuroscientist...). Compare this situation to that of an astronomer who wants to integrate the old age of the universe with his or her faith. Is this motivated by a desire to be respected by one's colleagues? Surely not. It is a commitment to truth that drives this. Or the same could be said of a geneticist who is grappling with the idea of a historical Adam as the sole progenitor of the human race. Indeed, the same accusation is often made by Ken Ham and colleagues towards Christian scientists who accept the evidence for evolution, "They just do that because they want to fit in with their secular colleagues." With the cake reference you even compare it to an act of indulgence. This is simply not a helpful accusation if we're looking for constructive dialogue. Naturally, every scientist tries to integrate familiar scientific knowledge with one's overall worldview. I think we should be looking beyond such taunts to be able to understand each other.

Blessings,
Casper

A quick aside to say that on reading this chain of comments, I relish the range of issues arising - as well as the quality of grace evident in the interactions. Antony, thank you so much for helping hold the threads together and at the same time flagging up other relevant issues we might discuss . My only plea is to try to simplify terms as much as possible for those looking on who are unfamiliar with the meaning of the technical labels - such as 'non reductive physicalism'

For now I simply wanted to pick up on the intriguing question of animals having 'souls' and with them the prospect of immortality. it is an question that, I confess, occurred to me only a few years ago but I think it worth taking seriously.
My own openness to the thesis that animals might have souls is rooted in my sense that the heavenly state appears to have much in common with the 'things' of earth. Even allowing for the apocalyptic language of Revelation, the reader is struck by the clear references to elements of the natural world -such as rivers and trees- as well as to the built environment -city structures. (However there will be no sea, it seems.) Is this all symbolic? I wonder. Perhaps the heavenly environment is a redeemed version of what we enjoy on earth. But perhaps I stray too far from the subject.
My line of thought here is that perhaps nothing is lost from heaven from what God has bestowed on earth. Is God only interested in the redemption of mankind? Not so according to Romans 8 which promises the redemption of the whole creation. Wouldn't it seem wasteful to dispense with the wonder of the animal kingdom? I
I am presently dipping into a book entitled 'CS Lewis on Scripture.' Lewis is open to the view that the immortality of animals is linked to the immortality of man. In this sense he shares the view of Wesley. He notes that in evolutionary biology man and animals share a common origin.(My paraphrasing of his view. ) This view is, I think, consistent with the contention that ' soul' and 'God consciousness' are quite distinct. It all does raise other less attractive possibilities. Is there a place for mosquitoes in heaven? Forgive this light diversion. We should return to the main menu!

Hi Iain,
You are right, specialistic terms can be thrown around so carelessly that we forget how they come across to others who are reading along. If it helps to describe "non-reductive physicalism" more elaborately, here's my shot at it for anyone who's interested:

Many people these days believe the "earthly realm" is one whole. This means that everything on earth is part of the same world, the natural world. The words physical and natural can be used interchangeably there. Note that the study of nature contains much more than "just physics". It includes chemistry, biology, neuroscience, and more... Under that approach, the physical world would include even animal and human forms of consciousness. We call this view of human nature physicalism. (It does not necessarily exclude the spiritual aspect of our nature, because that aspect could be seen as intertwined with the physical such as to be conceptually inseparable.)

However, some people (and especially, atheists) tend to mix this idea with nothing-buttery reasoning: "You are nothing but..." Fill in the option of your preference: A) a bunch of firing neurons, B) chemical reactions, C) elementary particles. These people are doing harm to reality by limiting it to one level of description (be it biology, chemistry, physics, or something else). This effectively "reduces" the truth to something lesser, something impoverished. This is called reductionism.

Now, there are people who endorse physicalism while taking care to reject reductionism explicitly. This gave rise to the term "non-reductive physicalism". Nancey Bussy is a prominent Christian theologian who gave a particular formulation of that idea. That's what has been discussed here.

As for your question regarding animal resurrection, here are my thoughts. I tend towards thinking that the promise of eternal life is confined to those who are made in God's image. We can live eternally because we are like Him who is eternal Himself. So the Resurrection would then be limited to those who are capable of relating to God. I believe that is how we gain eternal life: through a living relationship with God through Jesus Christ. I do not think individual animals are capable of this (but some alien races might be?). I do entertain the possibility that many of the forms of the natural world will somehow persist into the New Creation. Then again, that imagery from the Bible may be used simply because it is the only kind of imagery that we are able to understand right now...

This is somewhat of a tangent, but the reference in Revelation 21 of "there was no longer any sea" I believe draws on the theme of the sea as an image of destructive chaos. God subdued this chaos in Genesis 1 to establish our earth as an inhabitable place. God allowed the chaos to return in the story of the Flood in Genesis 6-9. Later, Jesus subdued the Sea of Galilee as a sign of His divinity. Revelation 21 then completes this theme "there was no longer any sea".

Casper

Thanks very much for your thoughts Casper. It is really good to have a neuroscientist involved in the discussion. Though I may disagree with some of what you have written, please believe that I respect your thoughts.

It would seem that your position is, as you say, of 'emergentism'. This maintains that consciousness emerges from the (non-reductive) network of neural activity in the brain. Philosophers tend to call this 'property dualism'. It is dualism in the sense that consciousness is not physical but it is nevertheless entirely produced by physical underlying mechanisms. Another word for this is 'supervenience' The mind/consciousness is supervenient (almost like something floating above the brain).In this view, which I assume you hold, consciousness is not independent and every form of consciousness (let us say a particular pain or a belief) has an underlying causal physical brain state producing it.

Probably the main criticism of this view is that we really do seem to have freedom in our thoughts. We can consciously decide to do one thing or another. There is autonomy. We are responsible individuals who can do right or wrong. Our freedom is central to our responses to one another and to God. If so, then our conscious decisions cannot be simply produced by physical states. They must be independent. This is because a physical system, such as the brain, is not free - it is simply subject to the laws of physics and the environment, a very complex machine. Quantum randomness does not help here either because there is no freedom in randomness.

You say that consciousness is a higher order phenomenon which can act indirectly on neural processes by constraining the possible outcomes. I do not see any freedom in this. It would be good to know how you see us having free-will.

You also say '.....science is strongly indicating a physical origin of consciousness'. I would really like to hear what is the evidence for this. I have not found so far anything in neuroscience that demonstrates a mechanism for producing consciousness.

I am interested also in your thoughts about how we continue to exist after death, before Christ returns. You say that we cannot exist without the body and perhaps we somehow exit out of time. The problem with this is that the body of the deceased is in time - and thoroughly dead and decaying! Where is the person then? We cannot say the person is part of that body. A non-material 'soul' however can exist as a person without the body.

Hello Anthony, thank you for your objections and remarks. They help to clarify the discussion.

Allow me to start with a general point. Earlier you said that your reasons for dualism are mainly philosophical ones. I think that is one of the major problems of discourse on consciousness. There is too little interaction with the actual neuroscientific findings and too much with our own personal lines of reasoning. To a neuroscientist, that sounds a bit like reaching a conclusion about the age of the earth completely based on philosophy instead of actually studying geology!

God indeed gave us the ability to reason, but this does not guarantee that our conclusions based on reason are always correct. On the contrary, lines of reasoning that appear to be intuitively correct have often been proven wrong in the past. One of the reasons to reject heliocentrism in Galileo's time was that we don't fall from the earth at gigantic speeds. This reasoning appeared logically sound back then, but it was ultimately incorrect. I see why the reasons you draw upon in your paper and in these replies would hold intuitive appeal for you. However, that does not guarantee they will guide you to the truth regarding this topic.

It is good that you asked for clarification on emergentism, because I find your description of it unsatisfactory. I would say that consciousness emerges from the interaction between brain and environment (note, this is not "just neural nets"). Causality here must be understood as a two-way street. It's not merely "an underlying brain state" causing consciousness. The daunting complexity of our neural system allows for causal influences to travel across many orders of magnitude in space and time. This is "emergence" properly understood. It's not about a mind "floating above a body"... That's totally misrepresented (I would say that's actually more a problem of dualism!). There is enough evidence both ways, from low-level physical descriptions to consciousness and vice versa. We haven't figured out the precise mechanisms, but we at least have enough evidence indicating that these phenomena are part of a single reality. (As an aside, I would not call this view "property dualism" because I believe every level of description exhibits properties that cannot be completely reduced to lower levels: plain physics is different from chemistry, which is different from biology, which is different from consciousness, which is different from sociology, and so on.)

There's abundant evidence for this two-way causality street between consciousness and other natural phenomena. I'll give a few examples.

Simple physical actions directly affect consciousness
- Everyday example: someone can become unconscious by shortly applying a force to their head (knock-out).
- An incision to the pathway that connects the two halves of the brain can literally split our human consciousness in two. This has been observed for many tasks in such split-brain patients.
- Applying electrical charges to certain neural pathways in live human subjects has directly improved conscious control over behaviour in people with Obsessive-Compulsive Disorder.

Consciousness affects neural processes (and more)
- For you as a medical doctor, a clear example would be the placebo effect. Simply believing in positive health benefits of a fake medicine has been found to correspond with actual changes in neurobiological functioning on lower levels.
- Consciously attending to stimuli has been observed to correspond with a remarkable brain-wide synchronization of neural activity. One idea here is that consciousness can have a broadcasting function, spreading relevant information throughout the system.
- Conscious intending can be envisioned as "self-programming". One interesting treatment in that regard is found in this paper.

You made this request:

You also say 'science is strongly indicating a physical origin of consciousness'. I would really like to hear what is the evidence for this. I have not found so far anything in neuroscience that demonstrates a mechanism for producing consciousness.

The two-way causality described above and many more findings suggest that consciousness is inextricably linked to neural processes. These are important pieces of evidence for the physical origin of consciousness. We didn't completely nail down the mechanisms. But it is unclear to me how you want to explain such strong interdependencies in a strictly dualistic framework.

Another crucial body of evidence is that consciousness has no difficulties to arise in physical systems, both in our evolutionary history and (on a more frequent basis) during embryonic development. Descartes in his time struggled to explain how mind and body are connected... and any dualist does, because the strictness of this dichotomy is artificial. With our current knowledge of evolutionary history and embryology, this problem becomes even more obvious. Why would a completely "physical" structure evolve towards a completely separate mental reality? Why would we need to develop elaborate neural architectures for consciousness if it's something completely separate? Instead, it is far more insightful to view it as one integrated whole. This is the consensus among neuroscientists, for what it's worth.

The max number of characters forbids me to go into the theological questions you asked regarding free will and between death and the Second Coming. I'll get back to that later. For now, I would suggest that "freedom" should be accurately defined and is relative (e.g., compare children and adults). We know that God is ultimately in charge and "knows all of our days" before we are born. Yet we are responsible for our own actions in this world.

Casper

Hi Casper. Many thanks. Apologies for taking time to reply - it has been busy here.

I do read neuroscientific literature and try to keep abreast of the latest research. I agree that we need to stay in touch with both science and philosophy and not speak to each other from isolated positions. My impression of most philosophers of mind is that they are fairly aware of the what science is telling us.

Your post is mainly asserting that neuroscience has now got plenty of evidence about consciousness. You say however "We haven't figured out the precise mechanisms". This sentence might make us think that scientists had worked out much about the mechanisms for producing consciousness. However you have not given any information about how the brain produces consciousness. I will go through some of your other evidence below - but if you make a statement like this, one would expect at least one neuroscientific piece of explanatory mechanism to produce conscious states. So far you have not done so and I have never read any.

You say knocking someone out affects consciousness. No one would deny this! However, bashing the hardware will inevitably affect how the person is. Substance dualism of the type Descartes espoused, links the person/soul intimately with the brain. Each needs the other (in this world). If you bash into my car then my car will stop but I am still sitting alive and well in the driving seat!

As for split brain - I have already mentioned this in another post. Clearly there are effects due to the 'wiring'. No one denies this. But one should expect to have two separate persons in the divided brain. My reading of the research and of the many thousands of patients who had this operation is that not one of them changes personality or feels 'different' in the sense of being either a different person or 2 conflicting people. Some recent research seems to confirm this: Pinto Y, Neville DA, Otten M, Corballis PM, Lamme VA, de Haan EH, Foschi N, & Fabri M (2017). Split brain: divided perception but undivided consciousness. Brain PMID: 28122878

You mention other evidence such as the fact that conscious states affect neural processes. I am not clear why this is any different from classic substance dualism which maintains, as you do, that there is two way causality between consciousness and the brain. None of this gives us any clue how the brain could produce consciousness.

You say that evolution seems to have easily produced consciousness from the physical over time. How easily and by what mechanism? - I submit respectfully that you do not know and neither do I.

Lack of evidence does not mean there is no scientific evidence for how the brain produces consciousness, but so far there is none.

I do not see this as a 'soul of the gaps' sort of argument to secrete some spooky soul into the machine. There are other reasons, which we can discuss again, why in principle we can never know how a conscious state is produced in physical terms.

Best wishes

Antony

Hi Anthony,
Please don’t feel the need to apologize, I’m thankful for the interaction we have and for the effort you invest in your writings. There’s nothing as stimulating as some thoughtful opposition to my ways of looking at the world. My own availability is very variable so I might reply slowly at times. Sorry for being again rather lengthy in my reply.

I see from your writings and the book you published that you are deeply invested in dualism, so I do not expect we’ll be converging here any time soon. It may be helpful to identify the common ground we have, apart from any labels that we might assign to our positions. We both believe that consciousness and the brain are intimately linked and that there’s two-way causality going on (although by no means a symmetric relationship). We both affirm consciousness as something causally efficacious, which is essential for any conception of human free will. The question, I suppose, is how this relationship can be conceptualized in a way that is most faithful to the actual truth.

[consciousness has a gradual aspect]
I think Descartes’ approach of substance dualism was a good first guess, given the knowledge available to him at the time. Conscious experience does have this “all-or-nothing” quality to it that invites dualistic descriptions. At the same time, there is a gradual aspect that should not be overlooked. One problem with Descartes’ thinking is that he viewed animal as automata and human beings as having “free will”, while both have very similar brains! The car analogy is not a helpful one, I believe, but I will take it up for the sake of the argument. Why would one car (“micro-organism” or “animal”) drive around completely reflexively, while the other more advanced car (“human”) suddenly needs to rely on a driver (“soul”) to function? Instead, it seems more elegant to view this as a continuum of freedom with respect to the environment. This continuum involves varying degrees of consciousness and human beings as a definite outlier. What definitely sets us apart is our awareness of God (as Iain referred to) and our elaborate self-reflection. One of the reasons we can view ourselves as an outlier is that most intermediate species became extinct.

The gradual aspect is what I meant to indicate with my references to evolutionary history and embryonic development. I think we both agree that a bacterial population and a fertilized ovum do not have anything resembling conscious deliberation. Yet, somehow, the first one eventually led to the evolution of human beings, and the second one routinely leads to fully mature, conscious human beings. How does such a transition occur in biological systems, if consciousness is of a different substance?

[mind-brain connection]
It can be insightful to explore your car analogy a bit more. One problem is that you as the driver of the car are still physically present in the car. That’s why you (and your consciousness) will be damaged if the car is hit. But if your consciousness was truly another “substance”, it would be more like controlling a space craft from a distance. Even if the space craft is completely destroid by an asteroid, you will still have the conscious experience of your black screen. This is definitely not the case when you’re being knocked out. In that case, your conscious experience is just gone for a moment. Even the spacecraft analogy does not represent real dualism because you still need a physical mechanism that sends, receives, and translates this signal to the spacecraft system. In your framework, how do you envision the contact between the mental substance and the physical substance? Why would we need complex brains for such contact? This can be seen as the dualistic equivalent of the quest for the mechanism for producing consciousness within physicalism.

An emergentist perspective on consciousness relies on neural complexity to capture the relationship between mind and brain and does not require different substances. I would not label it “property dualism” because emergentism allows for more valid levels of description than just two. We have physics, chemistry, biology, neuroscience… All require different paradigms for study, yet all are part of the physical. This pertains to your request for a robust physical mechanism for producing consciousness. There are several theories that have respectable support in observations from neuroscience (e.g., global workspace theory, local recurrent processing theory, entropic brain theory ), but we haven't nailed it down yet. Given the immense complexity of the brain, it is not expected to be an easy task. In any case, invoking another substance does not help us to understand the mind-brain relationship. It just shifts the problem to the question of how these two substances interact.

See my follow-up post below with my comments on split-brain patients, I didn't have enough characters for that here.

[split-brain patients]
I must say I'm rather surprised by the disagreement you express wrt the findings of split-brain patients. There are numerous accounts of split-brain patients who experienced conflicts of consciousness between hemispheres in various types of perception and decision-making, especially shortly after the surgery. For example, see this story of a woman named Vicki (note that the left, speaking half of her brain can only control the right hand):

‘In the first months after her surgery, shopping for groceries was infuriating. Standing in the supermarket aisle, Vicki would look at an item on the shelf and know that she wanted to place it in her trolley — but she couldn't. “I'd reach with my right for the thing I wanted, but the left would come in and they'd kind of fight,” she says. “Almost like repelling magnets.” Picking out food for the week was a two-, sometimes three-hour ordeal. Getting dressed posed a similar challenge: Vicki couldn't reconcile what she wanted to put on with what her hands were doing. Sometimes she ended up wearing three outfits at once. “I'd have to dump all the clothes on the bed, catch my breath and start again.”’
Read more in this Nature news article.

If this does not qualify as a conflict, I’m lost for words. There are many of such accounts. One especially interesting, well-documented case concerns a man who reported that he hated the left side of his body. When he was watching TV, his left hand (controlled by the right halve) would change the channels against the will of the right hand (controlled by the left halve, also speech control). Or when talking (left half of the brain) on friendly terms with another person, his left hand (right half of the brain) could suddenly lash out at that person in anger.

Such extreme dissonance is rare, but the experience of Vicki is very common and the most severe during the first weeks after the surgery. Our understanding is that neural plasticity allows these people’s brains to recover partially, because the surgery only severes the cortical connections and not the sub-cortical connections. Over time, these patients’ brains seem to be able to reunite their consciousness to some extent through subcortical connections. That is what happened in the article you cited, because those two patients had their cortical connections removed more than a decade ago! Those authors also note this in the final paragraph of their article. If the unity of conscious experience depends heavily on the post-surgery rewiring of the brain, that only seems to undermine your case. Even after all that time, these patients still show separate conscious experiences in some limited ways. They presented these patients with two different shapes, one for each hemisphere. The left half was able to consciously report seeing a “tank”, the right half was able to report seeing a “kangaroo”, but both halves were unable to report whether the two stimuli were the same or different (experiment 2C in that paper). This was even the case for simpler features like geometrical shapes.

Any trained neuroscientist would submit that the phenomenology of split-brain patients poses a significant problem for (substance-)dualistic accounts of human nature. Yet this is only one of many examples of basic physical interventions that directly change the properties of consciousness. Another interesting one is psychedelic drugs which can even trigger animal-like modes of consciousness in people. I would be happy to explore that one too, if you wish.

Casper

Many thanks again Casper. I will try to respond to your detailed and helpful reply.

Concerning animals: I have previously said in this forum that as far as I am concerned the higher animals (at least) may have souls. I am not aware of any theological objections to this.

You ask how does the non-material soul becomes partnered with the physical through evolution from bacteria and in the development of the embryo to become a human. We do not know, but this is hardly a reason to reject it. Just because it seems physically implausible or impossible is hardly a reason to reject it. After all the soul is not physical. If you begin from a physicalist world view then it is a problem. However our faith is surely founded upon the fact that there is far more than just the physical in reality.

Concerning the admittedly weak analogy of the person in the car; it is just an analogy and must not be taken too far. The person in the car stands for the non-physical person or soul. Even the alternative you give of control of a spacecraft from a distance is a physical operation using radio signals.

You suggest that when someone is knocked out then consciousness is gone for just a moment and this shows that consciousness is simply a physical phenomenon. However we do not know from this about the continued existence of the soul or person. All we know is that the physical part of us is out of action, and that this physical part of us, which expresses or transmits the person's thoughts is not working. I think we may be mixing up the difference between the person and consciousness. The phenomenon of consciousness requires the brain (at least in this world) and is an expression of the person or soul. That does not make it the same as the brain. Absence of consciousness does not imply absence of the person.

You also ask the age old question of how does the soul, if non-physical, communicate with the physical brain. Actually this is the sticking point for many who reject substance dualism. But just because we do not understand is not a reason to reject - again, as people of faith I do not find any contradiction at all. Every moment is a miracle.

You say the emergentist view of the mind/consciousness is well founded in neuroscience but not nailed down yet. It is far from nailed down. But perhaps we are writing at cross purposes here. I believe there may be breakthroughs in showing how the brain expresses conscious thoughts. There is of course a physical aspect to how consciousness is expressed. This is not the same however as nailing down the person or soul who experiences consciousness. Of course there is mystery here but even the fact of free-will is enough to show me that we are not simply physical.

Split brain: I have read carefully each case presented. Concerning Vicki, it is of great interest that though she has conflict with not controlling one side of her body, she always speaks as her usual unitary self. Actually the conflicts she experiences are very like what happens when someone has a stroke. Words come out that are clearly not meant - very frustrating! We do not then conclude there are two people in there. The person has wiring issues and the wrong expressions/actions are very common. In fact Vicki's case confirms quite strongly that there is only one consciousness there. Plasticity of the brain will then over time allow new connections/readjustments to be made. Exactly the same seems to be the case with the man trying to use the TV controller: to a doctor this looks similar to the conflicts patients have after a stroke, though clearly different because strokes rarely if ever cause the commissure to stop functioning. In each case the person is frustrated but still the same person. As far as the 2 shapes being shown to different sides of the brain, there is a useful review of a case on youtube: https://www.youtube.com/watch?v=82tlVcq6E7A In this youtube clip, the chap concerned is the same person, with no conflicting other selves, being just the same as before his operation. All the phenomena are explicable in physical connection terms. The fact that he is not conscious of what his right brain sees, does not imply there is someone else seeing it! If the left hand started writing something else such as "help, I am trapped in here" then I might agree.

I may sound as if I know all the answers, I don't! I am finding the conversation very helpful in expressing my own views on a complex subject.

We should really try to tackle free-will and responsibility. Can a physical object have free-will? Please join in this conversation all those who have an interest.

Hi Anthony,
Thanks again for the reply. I think we're making some progress here, especially with the distinction between conscious experience and personal existence.

[Consciousness and personal identity]

Anthony: "The phenomenon of consciousness requires the brain (at least in this world) and is an expression of the person or soul. That does not make it the same as the brain. Absence of consciousness does not imply absence of the person."

I can actually agree with this. An emergentist perspective captures how consciousness can be essentially different from, yet dependent on the brain. Personal existence as an emergent phenomenon in some way transcends even conscious experience. Then the question becomes whether that personal existence depends on our bodies. It turns out that personal identity and the human body are intimately connected as well.

This pertains to the argument from incommensurability of conscious experience that you made in your paper. From a neuroscientific perspective that argument does not really hold water. To truly share in your conscious experience, I would have to attain the same environment and the same body/brain as you, with all your past experiences etched into it. I can’t take along any of my own memories because those are etched into my own brain. If I would do that, I would essentially have to *become* you in a very literal way. Conscious experiences are incommensurable between persons precisely because identity and conscious experience are inextricably linked to the human body including the brain.


[Animals]

Anthony: “I have previously said in this forum that as far as I am concerned the higher animals (at least) may have souls. I am not aware of any theological objections to this.”

I thought you would probably be open to the idea of animals having souls. However, that does not solve the graduality problem. It requires you to draw a line below which organisms are considered too "low" for having souls. That's why I included microorganisms in my description. Looking at all the branches of the evolutionary tree from bacteria to microorganisms to higher animals, where does your mental substance "kick in"? That looks like a philosophical swamp to me! It's like looking at an embryo and trying to pinpoint when that clump of cells becomes "connected" to that mental substance. Within non-reductive physicalism, we don't need such an artificial boundary or appeals to miracles for that. Consciousness and freedom with respect to the environment can exist in a gradual sense.

[Invoking miracles]

Anthony: "You ask how does the non-material soul becomes partnered with the physical through evolution from bacteria and in the development of the embryo to become a human. Just because it seems physically implausible or impossible is hardly a reason to reject it. After all the soul is not physical. If you begin from a physicalist world view then it is a problem. However our faith is surely founded upon the fact that there is far more than just the physical in reality.
(...)
You also ask the age old question of how does the soul, if non-physical, communicate with the physical brain. Actually this is the sticking point for many who reject substance dualism. But just because we do not understand is not a reason to reject - again, as people of faith I do not find any contradiction at all. Every moment is a miracle. "

I think these two sections alone go a long way in illustrating the problem in our discussion. Just to be clear, I'm okay with things that appear to be physically impossible. After all, I also believe in miracles and the Resurrection of Jesus Christ. However, that does not mean it is wise for "people of faith" to accept implausible ideas. We still need to be open to perspectives that make more sense from the available findings. The communication between non-physical souls and physical bodies is such an age-old question precisely because substance dualism was never equipped to deal with it. Appealing to a constant miracle is not any form of explanation. If you need that to keep your perspective from collapsing, I'm afraid you've lost every comparison in terms of explanatory power. If the only way of enforcing "free will" in your framework is by invoking "mystery" and "miracle", any other explanation might appeal to that just as well.

I'll follow up with another post, but I want to echo Anthony's invitation for anyone who's interested to come and join the conversation!

[Free will]
In my view, we don’t need to appeal so much to mystery or to a “spooky substance” to allow for free will in a physical world. We just have to ask the question: “Free from what?” We definitely don’t want to be free from our brains, because our brains allow us to have freedom with respect to our environment. As I expressed before, consciousness understood as an emergent phenomenon can exert causal influence on the world. But that is dependent on our brains. Our understanding of maturation and healthy functioning of the brain is crucial for our conception of free will and responsibility. I know a philosopher of mind / neuroscientist who is working in an interdisciplinary setting for court decisions on the legal responsibility of children, mentally ill, and elderly suffering from dementia. From a legal perspective, the degree of personal responsibility for your actions is directly dependent on the functioning of your brain. This gradual understanding also makes more sense of freedom within the animal kingdom, without having to denote any artificial borders.

Now, a physical system might be deterministic for an outside observer such as God, which appears to contradict free will. But this is not the case if we define it as “free will with respect to our environment”. Besides, within Christianity, a similar tension exists between God’s sovereignty and human free will. We know from the Scriptures that God is sovereign over everything that happens and already knows all the days of our lives before we are born. Yet, we somehow have free will and responsibility right now, where we are. All perspectives have to deal with that tension. A soul substance doesn’t solve that.

[Is the soul physical?]
It is an important question how the human soul (or life, or personal existence) can be best conceptualized within a Christian worldview. You state with a lot of confidence that "the soul is not physical", but that is actually an open question. I do believe there is more than the earthly realm (or the physical). Then we're talking about the heavenly realm of God, angels, and demons. But if we look at, for example, the Lord's prayer, it is clear that humanity is living on earth and not in heaven. Note that my perspective of the whole of reality is not physicalist because I believe in a heavenly realm which can interact with us (that lies by definition beyond the scientific method). However, my perspective of human nature is physical. As humans including our souls, we are completely "earthly". When Jesus was with us in the flesh, He also became completely earthly for our sake. We are able to relate to beings from the heavenly realm, which gives rise to our spiritual life.

We stumble on the most intense mysteries when we consider the eternal Kingdom of God that will be established on Earth after the Second Coming. I’m completely fine with appealing to miraculous works when considering how God is going to resurrect us while our old bodies are long gone. One important hint is that resurrection involves new bodies that have some kind of continuity with the old ones, like Jesus’ body still having the marks from the crucifixion… My guess is that that allows our identity to continue its existence into the Kingdom of God. It also involves the famous paradox of “already, but not yet”. The criminal on the cross next to Jesus supposedly already entered that Paradise on that very same day he died! From his perspective, it’s like he didn’t even die in between. Everybody wrestles with that paradox. The image of a bunch of disembodied souls floating around, waiting for new bodies isn’t really supported by the Scriptures.

[Split-brain patients]
I think you’re missing the bigger picture here. Split-brain effects are very different from those of a stroke in which there is lack of control. All parts of Vicki’s body were showing healthy intentional behavior, but they were being controlled by two different parts of her brain which each hosted their own conscious intentions. It is the conflict between those intentions that caused the problem. If they were both controlled by a single “self”, there would not be different parts wanting different things. Vicki’s left half of her brain controls her speech and speaks as a unitary self. But if her right half could speak, it would tell us a different story, also as a unitary self! (This was shown by asking people’s hands to “speak.”) That tendency to perceive ourselves as one entity has been understood in terms of Gazzaniga’s interpreter theory. Thinking in terms of a unified self became hardwired in our brains because it works fine in most situations throughout evolutionary history. Even after being separated, both halves of the brain will be doing their utmost best to interpret everything in a unitary way. Yet, split-brain research has demonstrated these halves are each having their own conscious experiences, interpretations, and intentions (as demonstrated in cases such as Vicki’s). At times, that can lead to some strange incoherencies. In one famous study with split-brain patients by Gazzaniga, researchers secretly instructed the right half of the brain to perform a certain action. Then they asked the left half, “why did you do that?” The answer would involve some kind of confabulated reason for that action. The researchers knew that the reported reason was made up, but the left, speaking half of the participant’s brain believed it was a completely truthful answer. This experiment demonstrates that every half of the brain will attempt to interpret everything in terms of a unitary self, even if that interpretation becomes counterfactual.

Thanks for the interaction, Anthony :).

Dear Caspar. Thanks again for your reply and I do appreciate this discussion. I hope that others will become as fascinated as we are by the whole subject.
I do understand that you are not a 'physicalist' in the sense that you believe of course in God and in miracle, not least the resurrection of Christ. Nevertheless you hold to the concept that as humans we are entirely physical and there is no non-physical part of us. Though not orthodox in historical theological terms, this is the view taken by a fair number of Christian scientists and philosophers.

My own dualist approach is not simply 'appealing to constant miracle', as you infer. It is based upon an interpretation of conscious experience - some on philosophy and of course much based on Scripture. Unlike you I do think scripture is strongly in favour of a dualist view - not least some of Jesus' teaching (which is discussed elsewhere).

I could say that you are also just appealing to mystery when we talk about continuity after death - for instance. As a believer in the after-life you do need to have at least some rationality in approaching how you or I survive death. I do not think that resting on a concept of leaving the dimension of time holds water. If my body is dead then where am I then, at that moment? I see a dead person in front of me. To say they have left time for eternity and still live (minus that body which is still very much there) implies an existence separate from the body until the Lord returns. The only alternative seems to be some sort of pause in existence and then miraculous reconstitution of the exact elements of that body at a later date. That seems forced and does not do justice to the passages of scripture that say the person continues to exist. As Jesus said "He is not the God of the dead, but of the living, for to him all are alive." Luke 20:38. At the transfiguration Moses and Elijah appeared alongside Jesus - while their bones were in the earth.

It is too easy to mock an idea souls 'floating' around without a body after death......how do we know what form this takes? Moses and Elijah were not just floating around - as if there was some ghastly limbo. I was interested that at least you write that the question of the soul not being physical is 'an open question'.

Free-will: Your explanations do not seem to me to have any real substance (with due respect!). You talk of 'free-will with respect to the environment'. You have not explained this. Essentially the problem is that any purely physical system - your brain and the environment - is just that, physical. It is subject to the laws of physics and nothing else - period. What you are deciding now is therefore entirely and totally out of your control - each brain state (which might include a 'decision') is dependent on the prior state plus any inputs from outside (the environment). There cannot be freedom in this. Trying to avoid this conclusion by referring to non-reductive physicalism is how some attempt to rescue free-will. I have not time to discuss this here but find such arguments strained and ultimately false. I am not just trying to insert something spooky into our nature to account for free-will. There is, in my opinion, no other possible explanation. Some physicalist philosophers accept this and therefore have concluded, bravely and consistently, that free-will is an illusion. You and I do believe we have free-will and so need to tackle this equally consistently.

Regarding the state of people with say dementia - interestingly I find from my regular attendance with such folk that there is a remarkable continuity going on (particularly in committed Christians who continue to reflect fruits of the Spirit even when in an advanced dementia). Of course legally someone whose brain is damaged by dementia cannot make proper decisions - the hardware fails.

Split brain: I refer you to a paper here: http://www.brain-mind-institute.org/ICBM-2012/proceedings-html/full paper/paper 16.pdf The title is 'The myth of dual consciousness in the split brain'

This is a much more nuanced article which shows there are not two conscious minds in conflict. As far as the case 'Vicky' is concerned, the conflict between the two hands is still explicable in terms of connections - not 2 separate people living in the same skull. Because one side of the brain does not know what the other is doing, is hardly surprising given the operation to sever the connections, and the fact that one side is unable to coordinate with the other is entirely expected. The fact also that the person seems unconscious of what is happening in the right brain does not lead me to think the right brain is a separate consciousness. You say 'if the right brain could speak' - well it could communicate by writing. All such writing from the right side is simple recognition of an image or something projected to that side only - there is no indication of another person in there. I go back to my point that in these people there is no evidence of 2 people - always a unitary person persists. Their families know no difference in personality. Are you saying there are two people in there? For a Christian that is very loaded. Which is saved for instance? If I am right - and the evidence from split brain patients does support the continued unitary person, then we are not just physical.

Reading the literature I see that neuro-science really has no idea how conscious experience is produced. I note for example an article in Nature 2nd March which suggests consciousness may possibly be based around the part of neo-cortex called the 'claustrum' but there is no concept even in theory, of what could produce conscious phenomena. And so I think neuro-science needs to be very cautious and humble about this....far more than say trying to understand black holes. The very nature of conscious experience and its non-physical attributes, suggests to me that actually we never will have a physical understanding of it.