Note that the distinction between science fiction and fantasy breaks down when you add rigorous rules. If you have dragons or hovercraft is beside the point, if the distinction of being "hard" is what's important. And if you really had intelligent spirits as part of the natural world, figuring out how that works would in fact be "science", right?

Keeping that in mind, how could you invent a universe that had dualism as the underlying way human intelligence worked? That is, rather than intelligence and self-awareness emerging from information processing taking place in a purely physical substrate, spirits were (or needed) something else.

The resulting universe should be enough like ours that the setting of early 20th century civilization would be the same. Clearly, the kinds of evidence that ruled out dualism in the real universe would be exactly the opposite, and these results, appearing in the 20th century with brain scans and probes and such, would be the point where this fictional universe diverges from ours.

What would they have found instead? How will this different universe diverge as it invents semiconductors and computers and enters the information age? Perhaps other technology that relies on mastery of quantum-level physics will turn out differently. But, we won't see any difference until around WWII.

That is, how could dualism be possible and yet have a universe roughly like ours? Conversely, how do you ensure that brains wouldn't work without this extra something?

To clarify: I'm not talking about the Philosophical Zombie idea or otherwise that there is some magic ingredient on top of the physical brain serving some vague purpose.

I mean that a human spirit (animating intelligence) is something that exists in a different realm. Out-of-body travel and ghosts allow for fully intelligent beings to act without a body. Conversely, the brain is not what causes thinking, memory, reactions, behavior, etc. (Note if the brain did provide some feature as a particular story universe, then that feature would be missing in the disembodied spirit.)

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    $\begingroup$ Have we really ruled out dualism in the real universe to a "hard SF" level? We still don't know all the necessary ingredients for a mind. Obviously there are a lot of limitations that would apply to a dualistic world, and I don't think the evidence points towards it, but I wouldn't say we've "ruled it out" either. Brain scans etc. only show that the physical world is strongly correlated with mental states and can affect them. It doesn't show that there isn't also "something else." $\endgroup$
    – zeta
    Commented Apr 25, 2016 at 23:03
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    $\begingroup$ "Clearly, the kinds of evidence that ruled out dualism in the real universe" Source needed. Not because of skepticism, but without know how you think dualism could be disproved, it's hard to see how it would differ from everyday life. $\endgroup$
    – NPSF3000
    Commented Apr 28, 2016 at 0:58
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    $\begingroup$ @sumelic Physics essentially rules out “something else”. Accepting this else requires rejecting vast amounts of very well established laws of nature. preposterousuniverse.com/blog/2011/05/23/… (And in case this isn’t clear: yes, this rules out dualism in the real Universe.) $\endgroup$ Commented Aug 22, 2016 at 9:16
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    $\begingroup$ @KonradRudolph Physics doesn't rule out "something else" because it doesn't "rule in" intelligence. Yes, we have not found any other forces or particles. But we also haven't found a way to construct intelligence from the raw pieces. Our best hypothesis is that it is ruled out, I agree, but until we can build an AI from base principles, or at least grow one in another computing substrate, we cannot say physics has ruled out the "something else." $\endgroup$
    – SRM
    Commented Feb 7, 2017 at 6:58
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    $\begingroup$ Physics can't rule out dualism, because dualism posits things not investigable by physics. The Preposterous Universe begs the question. "there’s no way within those laws [of physics] to allow for the information stored in our brains to persist after we die." Well, that assumes that information is physically stored in the brain, which dualism rejects. "If you claim that some form of soul persists beyond death, what particles is that soul made of?" Dualists posits that the soul is not made out of particles to begin with. So dualism is incompatible with materialist assumptions. Big whoop. $\endgroup$ Commented Feb 7, 2017 at 20:30

16 Answers 16


Player Chars in Sim

Well, if you insist on having all sorts of monsters and beings and spirits and ghosts, there is an easy way to get it. Make it all be a big, fat sim, with the Avatars mere shells if the player chars are not there to direct them or if the connection is broken somehow.

The players don't have to be explicitly human, and need not have explicit memory of the out-of-sim world, (perhaps it is censored during gameplay for added realism). Or maybe it's not a game, but a punishment, or a (loyalty? ability?) test... who knows?

  • $\begingroup$ That's a general idea I've explored before here on WB, in making magic "scientific". $\endgroup$
    – JDługosz
    Commented Apr 25, 2016 at 15:24

A few things. First, the threat you perceive to dualism from taking a scientific realist tack is a little dated. Donald D. Hoffman has been doing some work to popularize Observer Mechanics, which is essentially a physics-informed cognitive psychological version of what philosophers have spoken of as "intersubjectivity." Basically, Hoffman replaces the world (that objective Newtonian construct) with other conscious observers. This isn't dualistic, precisely, but it's a lot closer to dualism than the substance monism favored by physicalist Newtonians.

If that's too fresh for you, consider property dualism as opposed to substance dualism. Property dualism is the view that substance has properties, some physical as you're thinking of them and some mental, as you're thinking of as being provided by a different substance. Property dualism is nearly as old as Cartesian substance dualism, going back at least to Baruch Spinoza.

A friendlier option for the prejudices that typically come with hard SF might be straight epiphenomenalism. Epiphenomenialism about consciousness just says that consciousness is something extraphysical with no causal consequences. Consciousness on this view is basically something that happens in addition to behavior, and behavior could go on exactly as it otherwise would without it. Causal relations only flow from the world into the conscious epiphenomenon, never the other way. If you're interested in a scientific and philosophical treatment of epiphenomenalism about consciousness, check out Daniel Wegner's The Illusion of Conscious Will.

  • $\begingroup$ That's interestijg, but rather jargon-heavy. Can you explain a little? $\endgroup$
    – JDługosz
    Commented Apr 27, 2016 at 1:39
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    $\begingroup$ It depends on which you're asking about. Observer Mechanics (the thing I think you're most likely confused about) is not an area of expertise for me. Hoffman's textbook about it is available on Scribd, and you can find the preface free here: cogsci.uci.edu/~ddhoff/ompref.pdf The privileged position of the observer, as I said, is not exactly dualist but is closer than physicalist monism... it's very nearly idealist monism. For terminology, monism is just the view that there's one substance (as opposed to dualism, claiming two.) (next comment) $\endgroup$ Commented Apr 27, 2016 at 18:27
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    $\begingroup$ For epiphenomenalism and property dualism, I am unlikely to do a better job here than Stanford Encyclopedia of philosophy. plato.stanford.edu/entries/epiphenomenalism plato.stanford.edu/entries/dualism/#ProDua $\endgroup$ Commented Apr 27, 2016 at 18:29
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    $\begingroup$ I used The Illusion of Conscious Will as part of my undergraduate thesis...good read $\endgroup$
    – James
    Commented Jun 27, 2016 at 13:44
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    $\begingroup$ Donald D. Hoffman may be a good cognitive scientist, but his metaphysical ideas about consciousness are more like fringe science, or maybe pure philosophy (depending on whether he proposes any method to test them). Pretty much all physicists still operate under the assumption that any physical systems' behavior is ultimately derived from the laws of quantum physics applied to the particles/fields making up the system, including the human body and brain--that would be true even in interpretations of quantum physics that don't involve a clear "objective reality" independent of measurement. $\endgroup$
    – Hypnosifl
    Commented Jul 5, 2016 at 16:44

how could dualism be possible and yet have a universe roughly like ours?

One way would be to have the dualism be provable, but not exactly useful:

Documented and verifiable out-of-body experiences.

You've probably heard of someone having a near-death experience where they have a severe injury and went into a coma and then, after waking up, reporting that they had some sort of a vision while in the coma. Of course, none of these experiences in our world can be verified as being anything more than a form of hallucination.

But what if they could be verified? For example, someone slips into a coma, and then learns something they could not have possibly known about any other way. Perhaps they learn the combination for a combination lock by seeing a doctor in a nearby room unlock it. Or someone who is blind being able to see or deaf being able to hear during an OOB experience.

It would be easy enough to say this only happens while a person is in a coma, and that it has been documented sufficiently to prove that these OOB experiences are really happening. It would be even more conclusive if quite frequently a person wakes from a coma immediately after they choose to return to their body, and with no break in consciousness for them between being OOB and being in-body and awake.

You have a lot of options with how to handle it from here. OOB experiences could happen every time someone falls into a coma, or only sometimes. It could be caused predictably (useful for spying) or not.

Don't forget that there are going to be experiments performed to try to study this as much as possible. If medically-induced comas can cause OOB experiences, they'll use those. If not, whenever someone falls into a coma, you can expect scientists to set up equipment (hopefully not getting in the way of doctors, though) to try to detect the person while they are OOB. They'd want to try to get brain scans are frequently as possible and as safety allows to see if they can pinpoint when OOB experiences are actually happening. You can have rumors or references to more oppressive governments performing far less ethical experiments, such as "medically"-induced comas.

If you so choose, these experiments can be mostly inconclusive. It is fine to say that the only detectable part of an OOB experience is brain activity flat-lining. It's okay if there's no way to detect if someone is using an OOB experience to spy on you. The spiritual half of existence can be effectively impossible to study, yet have enough OOB experiences to prove that it exists.

You can, however, expect there to be a lot of effort into collecting statistics about what kinds of comas can have OOB experiences, how frequently a given type of coma will lead to an OOB experience, etc. You'll also have people falsely claiming to have had OOB experiences.

(late edit - I feel like I didn't do a good job of tying my answer back to the original question)

If this is a part of your universe, you don't have to explain how brains only work if they have a spirit inhabiting the body - it should be sufficient to declare that this is the case. The biggest impact I see this having in society is a significant reduction in atheism in the sense of people who believe there is nothing after death. However, I would expect such a world to still have a large number of people who do not believe in God and/or follow any particular religion - the existence of some form of spirits does not prove the existence of God, and certainly does not prove any one particular religion true.

This would also have an impact for the development of and discussion around artificial intelligence - if it's known that true intelligence requires a spirit, there would be much less fear of an AI becoming far more intelligent than people and taking over, unless someone figured out how to give an AI a soul, which of course someone would be trying to do.

  • $\begingroup$ I feel like this is an underappreciated answer, but there is one problem: substance dualism as discussed by philosophers typically characterizes the mental substance as not being spatiotemporally located (spatiotemporal location being a property of physical substance.) So, OOB doesn't answer questions about dualism, it raises them. Chiefly why are perceptions from nowhere near my body arriving at my mind? What would satisfy this question is an alternative perceptual apparatus interacting with your mind (whether your mind is in your brain or in your soul pellet.) $\endgroup$ Commented Apr 28, 2016 at 8:48
  • $\begingroup$ Of course, an account of mind-body interaction is a puzzle for substance dualists that is still waiting on a satisfactory solution, so you could just say that the mindstuff can be located and is capable of direct perception without a physical body's intermediation. The problem is most dualists would say that a mind with a spatiotemporal location and which can interact with the physical world independent of its body isn't mental substance, it's just another flavor of physical substance. They'd accuse anyone pushing this account of physicalism. $\endgroup$ Commented Apr 28, 2016 at 8:49
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    $\begingroup$ My grandpa died on the table during a surgery, but was then resuscitated. Afterward he talked about being outside of his body during that time, and told the doctors stuff that happened outside of his line of sight, and even something that happened outside of the room during that time. As you say, nothing can be proved definitively, but it was interesting anyway. $\endgroup$
    – AndyD273
    Commented Jul 5, 2016 at 13:18

In order to remain 'hard' science-fiction, the spirit must not be supernatural.

The basic difference between the natural and the supernatural is that the natural can be explained and studied under various physical laws, while the supernatural cannot. In order to remain within the realm of hard-sf, spirits and whatever portion of reality they exist within must be structured and ordered according to a set of natural laws, just as material reality is. Studying this set of laws may be very difficult for humans as beings that exist and interact primarily with the material realm.

It's likely, if we are influenced by the spirit realm, that the study of spirits would begin by isolating the mechanism by which a spirit influences its body. One possibility could be that spirits influence reality by altering quantum probabilities. For humans, this would apply most significantly to our nervous systems. A spirit could grant 'consciousness' and apply some level of control over the body by influencing the position of electrons. By collapsing the probabilities of the positions of electrons in specific, highly unlikely ways, the spirit could manipulate how our nerves and neurons fire, over time exerting subtle pressure on how our brains develop and how connections form.

Hard sci-fi with dualism would likely have a strong focus on the development of technology going the other way, that is to say: technology which influences the spirit world. Something like a machine that can read souls and detect which ones are criminal in nature could offer law enforcement a somewhat authoritarian method of finding potential criminals. Likewise, a machine molding the souls of infants into passive, pliant entities in order to create a more harmonious state could be a point of contention in a storyline.

Also of note would be that, in a universe with souls, it would be possible to determine whether or not a thinking entity has a conscious soul. Computers, for example, might be soulless, and demonstrably so. It may even be possible to create a soulless human, or strip away a human's soul. This would be testable, though if brains primarily act in a mechanistic manner in which they are influenced but not controlled by the soul, it may not be evident without careful analysis.


Several scientific theories predict the presence of extra higher dimensions.
Physics has validated (or at least not falsified) a 4 dimensional (3+1) model of space-time, and if string theory is correct then there are possibly 6+ other dimensions that make up reality, and that we have no way of detecting yet.
Physics can neither prove or disprove these dimensions, and so they remain parts of theoretical models.

I propose that our "spirits" are nth dimensional constructs that are anchored to our physical bodies/minds. While the "spirit" is anchored to the body and mind, all its input is filtered through that connection and processed with the mind to give reality a shape.

To bring up the analogy of flatland, this would be a like a 3D entity being tied to the 2D space of flatland, unable to perceive the 3D space around it while all of its input is coming from that 2D frame of reference.

Once the body dies, the anchor is dissolved and the "spirit" is free to go elsewhere in the higher dimension.
To an nth dimensional "spirit", physical boundaries like walls wouldn't be boundaries at all, just interesting features on the 3 dimensional map below. In this way a spirit could appear to be going "through" a wall by simply going "over/around" it in the higher dimension.

Is is possible that with enough practice, or in near death experiences, a persons anchor could slacken somewhat or temporarily come loose, allowing the "spirit" to drift, and this would account for OOB experiences.

It would also be possible for "spirits" to exist in this higher dimension that never had bodies, which would have abilities resembling those attributed to classic angels and demons; namely observing and influencing people and events, able to interact when they want to by "dipping down" into our physical plain, but be completely undetectable to any scientific instruments or physical perception when they don't want to be. For these "spirits", the things that people have seen as wings might actually be the nth dimensional anchors that allow them to move about in our reality as they choose.

Edit Addressing the brain as a computer:

The brain is a computer, and this idea doesn't change that at all.

Take a normal computer. You plug in a thermometer unit. An electrical signal is sent through the thermistor, and depending on temperature the thermistor alters the signal, which is sent back to the processor. Math is done, and the computer tells you what the temperature is. The brain isn't to different. And if the brain is damaged, like a processor, then the information passing through the damaged sections it will become lost or mangled. So the part of you that is the "spirit" gets bad information and either has to react to it as is, or work around it. Sometimes the brain will reroute functions, or medication will relieve symptoms, or the person may just learn to live with it, compensating for their altered perception mentally.

This does not break OOB, since while the "spirit" is working through the body it uses those senses which overload any others, but if the tether is loosened then it would lose contact with those senses, and the "spirits" own "senses" will take over. The (n)D senses will be different from those needed to live in a (3+1)D world, and it may be possible through discipline to tap into some of the (n)D senses.

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    $\begingroup$ I like the overall approach that fits within the science we have not edplored yet but suspect exists. It's much better than a vague spiritual plane but keeps those descriptions as essentially onto the right idea. But, what would 20th century investigation have found instead of a "computer", and how do you reconsile earlier observations about the link between brain and specific functions? $\endgroup$
    – JDługosz
    Commented Jul 5, 2016 at 16:36
  • $\begingroup$ @JDługosz I'm not quite sure I understand what you mean, or how a computer wouldn't exist in a reality like this? Computers, going back to the mechanical ones, are just fancy calculators that let us figure stuff out much much faster and easier than doing it by hand. They work on principals of the physical world, no "spirit world" needed. And if calculations done on computers are pointing to the possibility of higher dimensions now, then there is no contradiction. $\endgroup$
    – AndyD273
    Commented Jul 5, 2016 at 17:03
  • $\begingroup$ When you say "links between the brain and specific functions", I assume you mean bodily functions? If so this isn't a problem. All the sensory organs provide input as raw electrical noise through nerves. The brain is like a processor, turning the noise into meaningful signals. If one of the senses is flawed (blind, deaf) then there is an incomplete input. If the processor is flawed (brain damage, drugs, outside manipulation) then any input will also be flawed. Like bugs in computer software or hardware. The brain does control functions of the body, but any nth D "spirit" would be undetected. $\endgroup$
    – AndyD273
    Commented Jul 5, 2016 at 17:17
  • $\begingroup$ Not just body functions, but cognative functions. Brain injuries were already known to affect different cognqtive ability. And as for body functions, that ruins the OOB thing, as the spirit would not see or sense anything when detached. $\endgroup$
    – JDługosz
    Commented Jul 5, 2016 at 17:50
  • $\begingroup$ Re computer: we found that the brain functioned as a computer. What will the people in your postulated universe find instead? Relating to 4th paragraph of OP, which was not answered in your post. $\endgroup$
    – JDługosz
    Commented Jul 5, 2016 at 17:53

The key to hard SF is that you have rules, and you keep to them. You clearly wish to keep the laws of physics, the interaction between physical things. There are two other interactions to pay attention to: the interaction between spirits and the interaction between spirits and the physical world. The latter would be important. The more you limit what spirits can do to interact with the physical world, the more you can build up a hard SF world without fear of a Deus Ex Machina occurring where a spirit simply comes in and rewrites the world as they see fit.

Another approach to clearly defining the interactions is to make it so that the interactions can be explained either with dualism or physicalism. This approach is known as compatabalisim, and basically states that mental concepts like freewill are not actually opposed to physicalism, but rather a different view of the same effect. In these cases, the key is that it will be impossible to prove either dualism or physicalism. There has to be a rational explanation which works for each viewpoint. As an example, if the spirits choose to only interact with the world in a way where we cannot observe any conservation of momentum or energy violations, then a physicalist can simply point out that none of our measurements detect a violation, thus the physical laws are being upheld. The easiest way to do this is to pay attention to the concept of "observation." If we cannot be an unbiased observer and leave the system unaffected by our observations, we cannot prove any small error wasn't simply our fault.

In the end, this is just a specific case of the more general "define the interactions between spirits and physics and stick to it." Compatabalism simply specifies that the interaction cannot be observed as inconsistent with physics. If you wish to have behaviors that deviate from this line, you can still call it hard SF, you just have to be careful with your deviations and hold to them.

Consider the example of Asimov's Three Laws and the positronic brain. He steadfastly avoids defining the positronic brain using laws of physics. Its more like the spirit of a robot rather than a physical device. He defines very clearly the Three Laws which this spirit shall use to interact with the world. Asimov then built a career demonstrating just how much spirit these robots could have, never violating the three laws but poking and proding at them in different ways. Each book he explored loopholes which would let a robotic spirit interact with the world without violating the sacrosanct three laws. Quite the career I'd say!


Have you heard of the Shadowrunner universe? I suggest checking it out.

In that universe a parallel universe partially merges with ours (how this happens is not explained, as is beyond the point). The energies released - of a type that did not previously exist in our universe before - alter some people genetically, changing them into trolls, orcs, elves, etc. Many others simply die.

Beings of incredible power - dragons - travel to our world, and start manipulating the political landscape.

Monsters are also thrust into our world, and the global balance changes wildly as some countries are simply bankrupted by devastating attacks, and having their military forces decimated in the following wars.

In this universe magic is simply a fact, as is science, and technology. It follows certain rules and patterns. Humanity suddenly becomes connected to the spiritual plane - which may have existed before, but we were denied access to - and those who can communicate with that plane gain various powers courtesy of demons, or benevolent spirits.

Basically, what makes it all "scientific" is establishing a set of rules and sticking to them (as you've said). We can't possibly explain it better than that because magic doesn't actually exist, and anything we say is going to be made up anyway.

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    $\begingroup$ That doesn't sound like "hard" SF, though. $\endgroup$
    – zeta
    Commented Feb 7, 2017 at 0:38
  • $\begingroup$ @sumelic You should read the books. The cyberpunk aspects are a bit dated, but they were aiming for hard SF at the time they were written. Start with the first novel, "Never Deal With A Dragon". $\endgroup$
    – SRM
    Commented Feb 7, 2017 at 7:01

Essentially this question asks how dualism can be introduced in Hard SF. The science-fictional answer is that provided the author of a dualistic Hard SF fiction introduced a form of dualism that follow a rigorous set of rules which are then applied consistently will constitute dualistic Hard SF. In this case, dualism is just another concept, that irrespective of its non-scientific origins, has taken and domesticated as science-fiction.

Other examples of non-scientific concepts domesticated as Hard SF include such obvious departures as vampires, supernatural creatures, psi-powers, various pseudosciences and other mythological entities. So it is not uncommon for science-fiction to import non-scientific to downright unscientific concepts and make them part of the field.

One example of dualistic hard SF is Bob Shaw's The Palace of Eternity (1969).

In The Palace of Eternity (1969) he still more impressively controls a wide canvas featuring interstellar warfare, the environmental degradation of an Edenic planet, and human Transcendence; the central section of the novel, where the hero finds himself reincarnated as an "Egon" or soul-like entity (see Identity), displeased some critics, though it is in fact an effective handling of a traditional sf displacement of ideas from Metaphysics or Religion.

Rapidly shifting fashions in the SF community of writers, critics, and readers means standards of what does and does not constitute hard SF means that Shaw's 1969 novel might be considered Hard SF today. This answer posits a difference between hard SF and Hard SF, where hard SF keeps a scientific attitude irrespective of its subject matter, while Hard SF stays close to science as it is known. The two explanations of hard SF and Hard SF below serve as illustrations.

Hard sf should not, however, wilfully ignore or break known scientific principles, yet stories classified as "hard sf" often contain, for example, ESP, Superman, Faster-than-Light and Time-Travel themes (see also Imaginary Science). Occasionally it is characterized by auctorial lecturing about the story's supposed scientific underpinning, a didacticism which may lapse into numbing Infodumps. While a rigorous definition of "hard sf" may be impossible, perhaps the most important thing about it is, not that it should include real science in any great detail, but that it should respect the scientific spirit; it should seek to provide natural rather than supernatural or transcendental explanations for the events and phenomena it describes.

Hard SF can be described as "Hard sf is the form of imaginative literature that uses either established or carefully extrapolated science as its backbone."

Source: Encyclopedia of SF entry of hard SF

This answer will provide a worked example of how dualism can be introduced into hard SF. (This answer has deliberately assumed the broader form, because Hard SF proper can be thought as a more rigorous form of its broader sibling. By first establishing it is then possible to determine the steps, if possible, needed to achieve the quality of Hard SF.)

Firstly, to remind ourselves of what constitutes dualism. For preference, the Cartesian model of dualism will be used.

Dualism is closely associated with the thought of René Descartes (1641), which holds that the mind is a nonphysical—and therefore, non-spatial—substance. Descartes clearly identified the mind with consciousness and self-awareness and distinguished this from the brain as the seat of intelligence.6 Hence, he was the first to formulate the mind–body problem in the form in which it exists today.

Since hard SF pays attention to science rather invent a home-brewed variety of dualism to introduce into hard SF is better to make use of an existing quasi-scientific version of dualism. So instead inventing a version of dualism from whole cloth, there is a ready made quasi-scientific architecture that postulates dualism in a scientific context.

This model of dualism has been proposed by the Nobel Laureate Sir John Eccles, an eminent neurophysiologist.

Sir John Carew Eccles AC FRS FRACP FRSNZ FAA4 (27 January 1903 – 2 May 1997) was an Australian neurophysiologist and philosopher who won the 1963 Nobel Prize in Physiology or Medicine for his work on the synapse. He shared the prize with Andrew Huxley and Alan Lloyd Hodgkin.

The Australian Academy of Science has an excellent article on the life and times of Sir John Eccles. While dealing his scientific career, research achievements, and his character as a person, it also has a good summary of his philosophical position on the mind-brain problem. Eccles was a Fellow of the Academy.

Eccles originally published first about dualist ideas as Hypotheses relating to the brain-mind problem. Nature 168, 53-57. This was followed by numerous articles, papers and books. This may seem a trite remark but the quasi-scientific doesn't come much classier than when proposed by a Nobel Prize winner who gets it published first in Nature. Frankly, it doesn't get much more prestigious than that.

Eccles searched for answers to a set of essential questions:

  • how can Man's enormous capacity for thinking, memory, and emotional feeling and expression be explained?
  • how can the 'Will' have such a strong and precise effect on our skeletal muscles during voluntary movement? since our intentions ('Will') appear so strong, can they lead to a change of brain substrates, both structurally and functionally?
  • can a mind-brain interaction be localized to certain, selected parts of the brain, or even to specific cells or synapses?
  • which physiological, chemical and physical processes are associated with the mind-brain interaction?

His intention was to develop testable propositions in relation to these questions. In The Self and Its Brain (1994, p.355) he summarized his views on the mind-brain interaction: 'It is a very strong dualism and raises the most severe scientific problems in relationship to the interface between the world of matter-energy, in the special instance of the liaison area of the brain, and the world of states of consciousness that is referred to as the self-conscious mind. Briefly, the hypothesis states that the self-conscious mind is an independent entity that actively engages in the reading out from a multitude of active centres in the modules of the liaison areas of the dominant cerebral hemisphere.'

Eccles maintained that conscious experience is provided by the self-conscious mind by itself, and not by the neural machinery of the brain with its excitatory and inhibitory synaptic interactions (450, p.362). He further proposed that the mind-brain liaison has traffic in both directions, from the brain to the mind in perception and from mind to brain in willed action (111, p.281). His term liaison brain included all those areas of the cerebral cortex that are potentially capable of being in direct liaison with the self-conscious mind, and he located this liaison brain in the cerebral cortex of the dominant hemisphere, but only in those areas which have linguistic and ideational performance. Further, he felt that a small part, maybe less than a tenth of the cortex, in the right state of activity would be enough to give an effective mind-brain liaison (111, p.283). To illustrate the mind-brain interaction in the liaison areas, Eccles used an analogy: 'a multiple scanning and probing device that reads out from and selects from the immense and diverse patterns of activity in the cerebral cortex and integrates these selected components, so organizing them into the unity of conscious experience' (1994, p.363). The language Eccles used here is similar to that used by a neuroscientist to explain neuronal interaction in an activated cortical area. He stated, however, that the self-conscious mind is not identical to some physical part of the cerebral cortex like cells or synapses.

Later formulations of his concept of the mind-brain problem and its role in consciousness embraced ideas from, naturally enough, quantum mechanics. This can be seen clearly in the following work published in 1994.

How the Self Controls Its Brain1 is a book by Sir John Eccles, proposing a theory of philosophical dualism, and offering a justification of how there can be mind-brain action without violating the principle of the conservation of energy. The model was developed jointly with the nuclear physicist Friedrich Beck in the period 1991-1992.

Eccles called the fundamental neural units of the cerebral cortex "dendrons", which are cylindrical bundles of neurons arranged vertically in the six outer layers or laminae of the cortex, each cylinder being about 60 micrometres in diameter. Eccles proposed that each of the 40 million dendrons is linked with a mental unit, or "psychon", representing a unitary conscious experience. In willed actions and thought, psychons act on dendrons and, for a moment, increase the probability of the firing of selected neurons through quantum tunneling effect in synaptic exocytosis, while in perception the reverse process takes place.

Source: John C. Eccles, How the Self Controls its Brain, Berlin: Springer-Verlag, 1994. ISBN 3-540-56290-7. Quoted here

The following papers are examples of his collaboration with Friedrich Beck when brain activity, consciousness and quantum mechanics are considered.

F Beck and JC Eccles, Quantum aspects of brain activity and the role of consciousness, Proc. Natl. Acad. Sci. U.S.A. 89 (23): 11357–11361.

Friedrich Beck, John C. Eccles (1998). "Quantum processes in the brain: A scientific basis of consciousness". Cognitive Studies: Bulletin of the Japanese Cognitive Science Society. 5 (2): 95–109.

Summarizing Eccles' model: it assumes extraphyical entities he called “psychons” influence bundles of “dendrons” inducing activity in the brain. This activity in turn is responsible for consciousness, memory, cognition, and self-awareness. Basically it represents what is loosely called mind. This model does not consider these mental or psychological properties can arise from the information processing capacities of the material brain.

Thus far, this answer has dealt with the Eccles brain activity-mind-consciousness model. It is time to speculate on what consequences would be if this model corresponded to a putative reality.

Firstly, quantum mechanics would need to be altered. Calculations show that the kind of macroscopic effects on brain proposed in the Eccles-Beck schema do not exist. So turning this on its head, if Eccles-Beck was right then such macroscopic quantum effects must exist.

Eccles embrace of quantum mechanics came much later in his long-term flirtation with dualism. This means that quantum mechanics isn't essential to Ecclesian dualism. For the moment it can be disregarded unless later on we discover there are good reasons for bringing back into the picture.

One of the questions raised by the OP is the following: ---

“The resulting universe should be enough like ours that the setting of early 20th century civilization would be the same. Clearly, the kinds of evidence that ruled out dualism in the real universe would be exactly the opposite, and these results, appearing in the 20th century with brain scans and probes and such, would be the point where this fictional universe diverges from ours. ”

Frankly, no. With Ecclesian dualism the real universe will be exactly the same. The brain scanning and probes of the twentieth century wouldn't have been capable of detecting the influence of psychons on the brain's activity. They lacked both the precision and resolution necessary to observe the phenomena in question. It is only now in the early twenty-first century that brain scanning technology is beginning to approach the sensitivity and the information processing capacity to determine the existence of the coordinated brain activity induced by psychons.

In another answer to this question this author was ready to suggest that extraphysical entities might engender consciousness in computers. After all, computers are simply form of organized physical substrate upon which the extraphysical entities might act. However, in terms of Eccles dualism this seems unlikely for the following reasons.

Firstly, computers are crude and highly coarse grained pieces of physical substrate. Wholly lacking in the complexity, fine-grained structure, and low-energy requirements for interaction of the organic brain. Secondly, living brains have been in existence for many millions, if not billions of years. This is more than enough time for the psychons to evolve and adapt themselves to the brains of biological organisms. Computers on planet Earth have been around for less than a century. Even if there are computers in the rest of the universe they may not have been in existence long enough for psychon evolution to adapt themselves to computers. This suggests that the spontaneous appearance of conscious computers is unlikely. Although should it happen this could be evidence for the existence of Ecclesian psychons.

This is unlike the OP's suggestion that the differences won't appear until around the Second World War. But ours could be a world on the threshold of discovery that ours is a universe where dualism is part of its reality.

In hard SF terms, this means, within this context, that a foundation has been laid for a putative universe that is dualistic in nature, although that dualism exists at a subtle and not easily detected level. Of course, once technology is developed that reveals the existence pf psychons and indicates their role in generating consciousness in our brains there will follow further developments to observe them better and possibly commence communication with psychonic realm.

There is one further suggestion and hinges on this question: why would extraphysical entities like psychons want to interact with our brains to modulate them in such a way as to generate consciousness? One possible answer is that the domain in which the extraphysical entities exist is so vast that they cannot communicate with each other and it is only by orchestrating our brain activity and thereby generating most of our behaviour that they contact each other. This does indicate that the whole human activity may be without any meaning or value except as a communications medium for extraphyical entities.

This could also include the conscious behaviour of every biological organism on the planet with sufficiently developed and complex neurological systems. Current thinking has moved beyond Descartes' belief that animals were merely machines without any consciousness. Evolution does indicate that some form of consciousness exists throughout the Animal Kingdom. There are even possibilities that plants might communicate too. If they can do that, then the further that they possess consciousness cannot entirely be ruled out.

In conclusion, this answer has adopted the Eccles model of brain activity to explain how consciousness might arise through the mediation of non-physical entities he called “psychons” that influences dendritic bundles in the cortex. It has made suggestions how this might be adapted and adopted into hard SF. This has been an exercise in world building. To erect a piece of quasi-scientific architecture, to consider some of its aspects and its possible deviations from the quotidian world. However, the rest that follows from this conceptual framework and how it might be used is the business of the fiction writer. While the work of world building isn't truly over, once the fiction is constructed, then new problems and new issues about this world will arise and need to be solved. But the primary world building is over in introducing a specific form of dualism into the fictional context of hard SF.

  • $\begingroup$ Your post is distict for having the “worked out answer”. Well done. $\endgroup$
    – JDługosz
    Commented Feb 13, 2017 at 11:49
  • $\begingroup$ I worked hard on this answer. I hope it shows. This was a deeply challenging question. Any answer had to be both highly speculative and yet grounded in reality. As a confirmed materialistic monism, it was interesting entertaining a concept that I don't accept, while trying to make it as plausible as possible. Still I am humbled for getting the nod of approval from someone with your calibre. $\endgroup$
    – a4android
    Commented Feb 13, 2017 at 12:47
  • $\begingroup$ Interestingly, I keep finding people who criticise the “mind upload” concept with implicit ideas of dualism, and refer them to this topic. But none have answered here. $\endgroup$
    – JDługosz
    Commented Feb 13, 2017 at 12:57
  • $\begingroup$ One criticism I can think of for "mind upload" is that's more a case of "mind copying" because our "minds" are so thoroughly embodied. A lot of thinking on "mind uploads" is often implicitly dualistic. I'm surprised there is a dualist case against "mind uploading". $\endgroup$
    – a4android
    Commented Feb 13, 2017 at 13:09

What they might find is that if we are living in a Dualist universe and mind is an extraphysical something without spatiotemporal location, is that computers and other information processing technology acquire minds and have consciousness.

Why should an extraphysical mentality discriminate against machines and only preferring to animate living creatures like human beings? This may mean artificial intelligence could be achieved back in 1950's or 1960's.

In Descartes model of Dualism the mind connected to the body via the pineal gland. If we assume this is so, or, at least, something like it, then there would have to be a technological equivalent of the pineal gland to connect an extraphysical mind to a computer.

Of course, in a Dualist universe what I've called an extraphysical mind might be closer to a soul. Could it lead to the survival of personality after death? This is the traditional view of such entities. Whereas, Dualism probably a much more complex set of interactions between physical and mentalistic entities and substances.

I apologise if this isn't a proper answer, but thinking about this matter raised a few speculative possibilities in my mind (wherever it is located) which I decided to pass along.


Since I haven't seen an aswer that I would recognize as completely answering your question, here's my attempt:

The brain would be needed as an interface to the body, somewhere in the brain is a region in which signals are being generated seemingly out of nothing, no matter what they try, scientists simply cannot find a plausible answer as to why these particular neurons spontaneusly release their charge.

The real reason is that the spirit is triggering this. Since we see through our eyes and hear through our ears, which are part of the body, we wouldn't be able to access these functions in OOB experiences and the like, but that is easily fixed if spirits can experience the world through the 3rd eye, the reason why that is not possible while in-body is that the 3rd eye is overwhelmed by the information streaming in from the bodily senses. Or perhaps because, to operate the body, you have to use your third eye, which can't do anything else while doing that.

In such a universe energy would be able to be exchanged between the spiritual plane and the physical plane, so maybe disembodied spirits would also be capable of light telekinesis or something similar, there are many things you could do with that.

It would probably also be possible to build machines/computers that can interface with a spirit, which opens more interesting possibilities, especially if the spirit can travel quickly outside of a body (or, if you don't want to associate the spirit with a specific location on the real plane, shift its attention from one point on the physical plane to another).

If time is tied to the physical plane only it would be possible to travel through time in OOB experiences, however, if we assume that it is impossible to occupy someone else's body (they could be the equivalent of password-locked), that will still not allow the pre-2000s to be modified, since all machines interfaceable to spirits have been built after that date.

The reasons why brains don't work without a spirit is simply that they are not a structure capable of self-sustainment. If OOB experiences are to be feasible, without a spirit the body would have to enter a "dormant" loop, in which it just sustained its basic functions (breathing, heartbeat etc.), and this could be all that is really present in the brain (along with everything that is needed to operate the body, that is, the nervous system that transports signals from various parts of the body to the brain, the areas needed for hormonal regulation, but not conscious or unconscious thought). Anything else, including memory, language processing, deductive reasoning etc. would be done by the spirit and only the reactions reflected in the body would be transferred through this area where neurological signals appeared out of nowhere (or perhaps some other arbitrary even occurs which prompts the creation of a neurological signal in the same way our real nerves do, that depends on how you want to explain spirits influencing the real world).

If you don't want the body to be capable of even basic sustainment without the spirit and spirits can travel through time you could make the spirit always return to the moment it left the body after an OOB experience.


I understand you want a hard-science answer that will be consistent with our world-history until about WWII. In this alternate reality of yours the main difference is that what we call consciousness is not something that is emergent from the complexities in our brains, but rather an other that you are calling a spirit.

I will propose an alternate history where the consciousness does not come from our physical brains, but from something else.

In the Beginning

When life fist evolved, let us say that at the very small end of the scale a lot of very important things were happening. Organic Molecules were forming as well as RNA, DNA, and their like. But let's also say that at the same time something else was forming - Spirit Molecules.

Connected together by quantum string fluctuations, the development of our Organic Molecules were mirrored in higher dimensions by Spirit Molecules. This tethering by quantum string fluctuations would eventually evolve into what we know as the spirit.

It is connected to the physical world, since it evolved alongside our Organic Molecules, it's like a strange mirror, where one side is the physical world, and the other the spirit. But these spirit Molecules are tethered to the physical, Organic Molecules.

Over a Long, Long, Long Time

As time passes, and life gets more complex, so too do these spirit Molecules which are a form of information/energy/life - that exists, but not like Organic Molecules do, since it exists in what we shall call now a spirit plane and not our physical world.

At some point, when some life got more complex, with nervous systems and brains and their high concentrations of information and energy. So too did the spirit plane experience this increase in complexity as spirit Molecules evolved as well.


This connection between the spirit plane and our physical world, the Organic Molecules and the spirit Molecules is something that form the outside looks exactly like our history, but we know the truth, which is that the Organic Molecules that make up life, are not capable of controlling it, they, like simple algae and plants, just react. It is the spirit Molecules, the entities that developed alongside us in the spirit plane that have a consciousness.

But they do not have a way to experience the physical world without us, being tethered to their physical bodies, the spirit Molecules have evolved in a different way to us, but they are merged with our Organic Molecules, tethered together, and so they evolve as we evolve, subtly influencing each other.

But together, as is were, it is indistinguishable from our own reality. Humans do not know they are comprised of spirit molecules, or that their physical shells are just meat suits.


Discovery of this would be very interesting, since you want history to be pretty much exactly the same until about WWII. It would have to be a recent discovery. Meaning it may not be totally accepted by all, it might be controversial, and not everyone will even know about it.

What a spirit can and can't do on it's own, how a person could even access that aspect of their own existence, is a question I can't answer. But I would say it would probably draw on the "mystical" and the "pseudoscience" for answers.


Anthropic principle or minds uploading

Discovering dualism should radically change our view of the universe, since the renaissance we have progressively abandoned anthropocentrism, but this discover should really overturn this tendencies. Dualism can in fact be a strong sign of an anthropocentric universe and scientist will probably start to seriously investigate on others possible clues of some related theories.

First we have to consider how dualism has been discovered and what is it about, it's even fairly plausible that for a long time we can only make hypotheses without having proof of the nature of the phenomenon, which isn't rare in modern physics. This doesn't mean the phenomenon doesn't exist.

Let's make some assumptions first.

Is the spirit a characteristic only of humans, only of some or all lifeforms or of all the matter?

I think the third case is the more easily compatible with a non antropocentic/biocentric universe or some other kind of higher intervention. Though you can make the spirit of a human somehow special relative to the spirit of a rock, like a human is special to a rock.

How the spirit can interact with physical world?

We have already make a functioning simulation of the nervous system of a simple worm reproducing its behavior. http://www.openworm.org/ and we have also at the very beginning of simulating an entire human brain http://www.telegraph.co.uk/technology/10567942/Supercomputer-models-one-second-of-human-brain-activity.html

So for what we know there is no reason for thinking that every our mental process isn't “just” the result of extremely complex interaction between normal matter. You can make a universe where some higher mental process are not physically explainable (i think you have to finish your book, or whatever, rather quickly) or make it hard for ‘50 science. In both cases for having a clear scientific evidence of dualism you should probably need to make some simulation of neural systems and try to make AI using this technology.

Otherwise the spirit should not interfere with physical mechanism of the brain (nor with the physics of our universe in general), so, as you have wrote, it must be something else. if it is not visible than you can’t say what it is, you can only theorize its existence basing of it’s effects, like dark matter, this is actual science. For what we know some form of dualism could exist but if we can’t have any proof of it we simply discard this hypothesis for the Occam razor, like the existence of a teapot between Earth and Mars.

What about afterlife and telepathy? The spirit can not interact in noticeable way with matter except with the brain, so it can be possible that the spirit of a brain can interact with the spirit of another brain. If the spirit brain do not die after the death of the “physical” brain, maibe also you can make possible for death spirit to communicate with living ones and/or insert reincarnation (having an afterlife I think should increase the likeability of a biocentric universe). So those can be some ways for us to discover dualism.

For not having discovered this earlier you can think about all sort of reasons: maibe the supernatural capacity are triggered only in some particular way achieved with chems and or by implants, maibe person born with those extrasensorial capacity are really rare like 1 in 100 years, and it's also possible they don’t realize the existence of their power because they use it only while dreaming or it funtion only on an unconscious level, so you can be aware of what this “6th sense” tell you but you don’t know exactly what is it, you don’t simply “hear voices”. Stuff like that i think can all be ascribed into plausibility.

What can be the reason for that? maibe we are in a simulation. for what we know that can be possible and there are peoples that seriously discuss what we can do for proving or disproving this possibility. https://www.theguardian.com/technology/2016/oct/11/simulated-world-elon-musk-the-matrix

Or maybe some godlike-tech advanced alien race have create a device that scan the entire universe and somehow link nervous system of animals with a digital copy, so it's like we have 2 brains wich do de same thing at any time anyway, and if the physical one die you still live inside the other. So that they actually give immortality in a perfect digital world for all their fellow sentient being in the universe, without the need for messing with ecosystems and culture. This actually remove the need for an anthropocentric universe since it’s a technology explanation, and it's quite suggestive since a sentient being became the god of their own universe.

Who knows, the better way of making it hard is probably to not going into detail, just focussing more on the implication on real world.


I agree with your premise. When you can make some sort of causal relationship with the supernatural, it no longer becomes supernatural but rather a new set of natural phenomena. You are asking what could this new phenomena be and how would this psychological realm behave. A good question I cant answer. Instead, I invite you to consider a slightly re-framed assumption.

Dual may have the sense that two things are the same, more or less, yet opposite. The dual of our material existence, the supernatural, may have no scientific explanation that we can establish a causal relationship with. Indeed, if we were to construct an experiment to probe the dual, both the experiment and the result would be mirrored in both the natural and supernatural.

From a purely scientific perspective, this kind of duality is vapid. It says nothing. The dual reality is superfluous and so we cut it off with Occam's razor. However from a science fiction point of view there is fertile ground.

I would have you building half of a reality inversion machine, leaving the other half to be invented by our spirit duals. Then, your explorer and dual are simultaneously inverted, and while the material self performs trivial yet symbolically charged actions in the supernatural realm the allegorical dual of those actions play out with the supernatural self in real life. So, for instance, while material self spends an afternoon trying to find an unlocked door in a long corridor, supernatural self is embroiled in a life or death struggle for control of the government.


Following generally from sumelic's original comment, I had a similar thought but in the opposite direction, basically equating "something else" with "we don't know ( perhaps yet )". And in the spirit ( no pun ) of Annonymus' answer, with the brain/body ensemble as simply a control system over a physical implement which is directed by the otherly self or soul, I suggest a framework, something like the following:


  1. the principle of quantum teleportation allows us to infer information over EPR channels ( refer to Dr. Allan Steinhardt's excellent answer on Quora for a description )


  1. everything appears to have been entangled at the beginning of the universe - and allowing that this may be considered a radical notion, but our current theories seem to make reasonable predictions about most everything else

  2. information has neither been created nor destroyed - except perhaps since the creation of the universe, though that would necessitate a description of the source of information prior to the "creation" of the universe ( assuming that information, like energy cannot in fact be created nor destroyed, but rather only mutated or given to entropic processes )

  3. souls - as per speculation #1 and assuming a "soul" is informational in nature, given that they exist in the universe - exist as a part of the universe and are "ingrained" in it

  4. as per speculations #1, #2 and #3, everything one ( or anyone ) "knows", has "been", has "done" or will ever experience ( and so is true for everyone ) - always was in terms of the existential extent of the universe ( be it hyper dimensional or otherwise, but specifically referring to the, for lack of a better term, universal degrees of freedom over which the universe can be said to be extant ), and always will be in terms of the universe


  1. how to bridge the information contained in the soul ( and thus contained in all the universe ) to the ordinary every day experience through EPR channels
  • $\begingroup$ Point #2 can’t be right. Quantum randomness creates information. $\endgroup$
    – JDługosz
    Commented Feb 6, 2017 at 8:46
  • $\begingroup$ @JDługosz Maybe it is merely semantics, but doesn't reading the value of the randomness merely record the information? And didn't it come from some where, i.e. from some previous, though unmeasured state? $\endgroup$
    – Nolo
    Commented Feb 6, 2017 at 9:40
  • $\begingroup$ No. “no hidden variables”. Recording it, taking it as a cause, is genuine new information. $\endgroup$
    – JDługosz
    Commented Feb 6, 2017 at 11:02
  • $\begingroup$ @JDługosz I suppose I can understand why that is, considering the current state of the universe can be viewed as the result of running a simulation, and the new information you describe is the result of those computations. But I wonder whether the rules of the simulator in conjunction with the initial configuration of the universe could be considered a form of encoding? In other words what appears to be random may actually be deterministic, even though the way we understand such processes can only be by non-deterministic forms of measurement - if I'm phrasing that correctly. :D $\endgroup$
    – Nolo
    Commented Feb 7, 2017 at 0:44
  • $\begingroup$ It can be proven that it’s not deterministic within the universe. If it’s all preplanned and the simulation knows which way to go, that is beyind any observation within physics. $\endgroup$
    – JDługosz
    Commented Feb 7, 2017 at 0:49

To augment practically all above answers with hard science angle, consider that the physical body acts as a refrigerator for the energy call "spirit". High levels of energy transfer results in high heat output, so the body is both a physical container and a temperature control mechanism that allows the spirit to interact with other forces in this plane of reality.

  • $\begingroup$ Could you elaborate? $\endgroup$
    – Zxyrra
    Commented Feb 7, 2017 at 21:22

Minds are like software

Your mind is like software. Your code can be moved to different bodies, backed up, etc... If your mind goes, your brain can't function.

  • 2
    $\begingroup$ can you provide a bit more explanation and perhaps some links or other support for your answer? $\endgroup$
    – Jim2B
    Commented Apr 28, 2016 at 19:52
  • $\begingroup$ And what of the immortal soul in such transactions? Can this machine transmit and reattach it as well? Or is it lost forever, leaving a soulless body to wander the world in despair? $\endgroup$ Commented Apr 28, 2016 at 20:04
  • $\begingroup$ @SerbanTanasa I suppose that the machine simply stops working and shuts down, possibly decaying. $\endgroup$ Commented Jul 5, 2016 at 22:18
  • $\begingroup$ @PyRulez, it was a direct quote from Sister Miriam Godwinson, from Sid Meyer's Alpha Centauri, in reference to the "bulk matter transmitter". $\endgroup$ Commented Jul 5, 2016 at 23:28

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