Science and the Search for the Soul (3): Pluralistic Causation and How to Avoid the Reductionistic Fallacy


Many sciences use a broad model of causation that allows causal relations to exist on many levels, including social interaction; a reductionist view, by contrast, would even hamper scientific progress instead of supporting it; and agnosticism, after all, is a viable and rational position in a debate if neither side can present convincing arguments.

What we discussed so far

In the first part of this series we learned something about the controversial view that the person is identical with his or her brain and became acquainted with the idea of the theoretical physicist Sean Carroll who stated that the physics underlying our everyday life is completely understood and all we need to understand the everyday life’s phenomena.

In the second part I argued that physics is not the only domain where we can get to know what kind of things exist and discussed that compatibility between the sciences is all we need to make progress in understanding the world; actually, a reductionistic account would hamper scientific progress, in my view.

In this third and final part I will introduce a broader view on causation and also return to the question of whether agnosticism with regard to the existence of a soul is a rational alternative position.

Causation broadly perceived

In discussions about the theory of science, particularly with respect to the relation between psychology and neuroscience, I sometimes meet people advocating the view that we can only speak of a causal relation on the physical level and in terms of energy transfer. This is an old-fashioned understanding that I like to call the cueball model of causation:

When you strike the white ball on the billiard table with your cue, you do this in order to transfer your cue’s energy by means of the white ball to other balls – to make them move in a certain way, usually to win the game. This is a nice and simple model of causation, but it becomes problematic if we want to transfer it to all situations in the world that are much unlike the happenings on a billiard table, for example, when my compliment makes you feel better and you smile in consequence.

A reductive account of science

Reductionism promises simplicity by claiming that ultimately, everything is just physics. However, this view is not only counterintuitive, but cannot explain the success of ever more individual disciplines instead of reduction to physics.

A common test for a causal relation in the behavioral, social, and life sciences goes as follows: If variations in one variable (psychologists call this the independent variable, IV) are followed by systematic variations in another variable (the dependent variable, DV), not the other way round, and if there is no third variable (a confounding variable) that can explain the variations in both variables, then there is evidence for a causal relation between IV and DV. The IV in my given example would be my verbal expressions, the DV your facial expression, and a confounding variable might be some person standing behind of you threatening you with a gun and saying “Smile!” every time I happen to pay you a compliment.

The power of a compliment

If my compliment were only related to your smile whenever that third person shouted “Smile!”, we should have serious doubts about a causal relation between this IV and DV; but if we found out that systematic variations of my verbal expressions varied with your facial expressions, particularly that my compliments correlated with your smiles even in the absence of the third person giving the commands, then we would have evidence in favor of a causal relation. We would then be justified to say that, other things being equal, my compliments have a causal influence on your frequency of smiles.

Given that we presently know next to nothing about the physical principles underlying mental phenomena and achievements, there is no reason to assign the level of neurons [or physics] a privileged explanatory role. (Rainer Mausfeld, 2012, Frontiers in Psychology, p. 4)

Such relations can even be used to make and test predictions about human behavior; and to describe such relations, we need not invoke the three basic physical kinds of particles and forces that Sean Carroll claimed underly everything in our everyday life and that are sufficient to explain everything that happens around us. Even worse, invoking these particles would not get us anywhere in understanding or predicting what is happening. We would lose much if not everything of what we know about the everyday life including the causes and effects of human behavior.

The world is more than just physics

Does our incapability to formulate my compliment and your smile in physical language mean that they do not exist? No. Does it mean that the former cannot cause the latter? No, again. If we lived in a world of pure physics – electrons, neutrons, and protons –, then most of our everyday world would not exist in the first place. Even physics as a scientific discipline would not exist. Physics is not the only domain in which things exist.

Chairs, thunderstorms, trees, and clowns all do exist; and they can have effects on others things. Sometimes we may be able to explain the effects of one of these things in virtue of some of their physical properties; but most of the times this will not work, just because this is not a simple part-whole-relationship (philosophers call this “mereological”).

A pluralistic account of the sciences

Pluralism explains the manifoldness of scientific disciplines and leaves enough space for investigations, explanations, and predictions on various levels, thus supporting the progress of science.

The clown is not a mere aggregate of her electrons, protons, and neutrons – even if these particles are necessary for her existence – and we do not laugh because, say, the electrons are bouncing that way instead of the other. We cannot even see the clown’s basic physical particles. This is neither a problem for the physicist investigating basic particles nor for the psychologist investigating humor, but only for the physicalist who thinks that everything that exists is purely physical or that all descriptions can and must be translated into physical descriptions. Yet, the theoretical physicist Sean Carroll claims:

All we need to account for everything we see in our everyday lives are a handful of particles — electrons, protons, and neutrons — interacting via a few forces — the nuclear forces, gravity, and electromagnetism — subject to the basic rules of quantum mechanics and general relativity. … That’s a remarkably short list of ingredients, to account for all the marvelous diversity of things we see in the world.

This is not a scientific statement, strictly speaking, because it is either wrong or an unfulfilled promise. We have not the slightest clue how to describe the “marvelous diversity of things” of everyday world in terms of electrons, protons, and neutrons interacting via three elemental physical forces. That is also why we have all the other academic disciplines, in the first place, because sticking to physics will not get us too far when describing the behavior of, say, hemoglobin, clowns, or markets. Only a physicalist like Carroll who says that everything can be accounted for by physics has a problem with this absence of a purely physical description of our everyday world, not a pluralistic researcher using his or her methods to understand the world.

Agnosticism is a viable alternative

At the outset of this series, we briefly discussed the rationality of agnosticism, the idea that someone is undecided between claims that there is or that there is no immaterial soul; that there are or that there are no deities; that an afterlife is possible or that it is impossible. Agnosticism is a humble middle position between those opposing claims on the existence of some kind of things, a position that implies that if we cannot decide this debate, then we should perhaps remain undecided.

Portrait of Thomas H. Huxley

Thomas H. Huxley (1825-1895), also known as "Darwin's bulldog", wrote a famous essay on agnosticism. He wondered that his contemporaries of the 19th century had difficulty accepting his philosophically humble position.

If someone formulates a variant of an immaterial soul or an afterlife that does not violate basic physical laws or that of another established science, there need not be a problem. I wrote already in the first part that I do not know a convincing argument in favor of any of these entities. A theologist or spiritual teacher might have a different view on this issue, though; but the important philosophical point to make here is that just because physical theory does not refer to an entity this does not mean that it does not exist. So agnosticism regarding a soul or afterlife can be a rational position, according to the understanding of the biologist-philosopher Thomas H. Huxley:

Agnosticism, in fact, is not a creed, but a method [...]. Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect do not pretend that conclusions are certain which are not demonstrated or demonstrable.

This difference is of practical relevance because in recent discussions, particularly in science blog forums, people with different kinds of beliefs are sometimes considered as educationally retarded. There certainly are educationally retarded people in the world, but not in virtue of believing in the existence of entities not accountable for by basic physics. Those who believe in the existence of souls or an afterlife should present good and testable reasons for their position when they are arguing with us; but also those who think that only physical things do exist should present good and testable reasons for their philosophical stance.

A social-science alternative to metaphysical debates

Personally, I think that this metaphysical debate does not get us very far. Instead, we might actually wonder (and investigate) whether those people telling us that there are souls or afterlives might have hidden interests for telling us so, for example, to first make us feel guilty or afraid and then offer us their unique solution to save our souls, a kind of spiritual salvation.

We can investigate power structures of institutions based on and promoting such beliefs; but likewise we can ask ourselves whether those people who tell us that all that exists can be ultimately accounted for by physics might have hidden interests to make us support their ends with our means. For example, they could directly benefit from spreading the belief that their science is the ultimate access to reality when applying for research grants.

Such questions about people’s interests are not metaphysical and can have quite an impact for people’s everyday lives. Even if we cannot tell whose beliefs are the true ones in such debates, the behavioral and social sciences provide means to investigate why some people hold such beliefs.

P.S. Ironically I finished this post today while attending a workshop on Laws of Nature including a presentation titled "Why Physics Can't Explain Everything" held at the Technical University of Munich.


20 Responses to “Science and the Search for the Soul (3): Pluralistic Causation and How to Avoid the Reductionistic Fallacy”

  1. Troy McConaghy Reply | Permalink

    You wrote:

    We have not the slightest clue how to describe the “marvelous diversity of things” of everyday world in terms of electrons, protons, and neutrons interacting via three elemental physical forces. That is also why we have all the other academic disciplines, in the first place, because sticking to physics will not get us too far when describing the behavior of, say, hemoglobin, clowns, or markets.

    (End quote)

    Are you sure? Hemoglobin, for example, is just a molecule, and we have great models for how molecules behave (based, ultimately, on the fundamental physics of its constituent parts). What is a clown, if not a collection of molecules, and what is a market, if not a collection of clowns?

    • Stephan Schleim Reply | Permalink

      Hemoglobin: We may have great models, but do we have great purely physical models? I think not. Hemoglobin is a molecule, yes, but it is not "just" a molecule; it has an essential function in the metabolism, providing organisms with oxygen and energy, see aerobic glycolysis and oxidative phosphorylation.

      There are also physical accounts, yes, for example, that different hemoglobin molecules (e.g. hemoglobin, oxyhemoglobin, and carbonmonoxyhemoglobin) have different magnetic properties (Pauling & Coryell, 1936, PNAS 22 (4) 210-216 – actually a contribution in chemistry), a basic physical property underlying BOLD fMRI.

      What is a clown, if not a collection of molecules…

      A person wearing a funny hat and nose and entertaining people with her tricks?

      … and what is a market, if not a collection of clowns?

      Well, this one is irrefutable, I admit.

      • Troy McConaghy Reply | Permalink

        Purely physical models of hemoglobin exist. I'm surprised you think otherwise. Look up "molecular dynamics" to get a sense of how those models are built and used. If you'd like to read some papers about simulating (purely physical) models of hemoglobin, do a search for "simulation of hemoglobin" on Google Scholar.

        • Stephan Schleim Reply | Permalink

          Thanks for the hint – the question then is, of course, what we mean with "purely physical".

          In the context of this blog, I referred to Sean Carrolls understanding that everything in our everyday life can be accounted for by electrons, protons, and neutrons interacting via three forces (this was just his argument derived from Quantum Field Theory).

          The hits on Google Scholar that I have skimmed seem to rely on a more diverse understanding of what hemoglobin is made of; this is particularly what I know from the examples of papers in neurobiology that I read about the function of hemoglobin – Carroll's basic particles are not even mentioned in those papers; and for a good reason, because they usually do not have an explanatory function for what neurobiologists want to understand.

          Even if there were such simulations (i.e. models), this is only scarcely relevant to this discussion: For first, they needed to be not just models of some aspect of hemoglobin, but all functions of hemoglobin and second, hemoglobin is just one aspect of everyday life (if it is an aspect of everyday life at all, and not just a microscopic entity), whereas Carroll claimed that the whole of the everyday life's diversity could be understood in terms of three basic physical particles and forces.

          The reason for this discussion is to show how strong – implausibly strong, in my view – this assumption is that everything can be explained in terms of these three particles and forces.

          If we want to understand the world, then we have to, in my opinion, take account of a diversity of things, not just three kinds of particles and forces.

  2. Balanus Reply | Permalink

    Dear Stephan, you wrote:

    »We would then be justified to say that, other things being equal, my compliments have a causal influence on your frequency of smiles.«

    Yes, of course.

    But nevertheless, this causal connection is based on a vast amount of purely physical events, i.e., causal relations.

    You can’t escape from the material world. Without the causal relationships on the basal physical level, there were no any causal relationships on the higher levels of description (like psychology). If you cut the physical connection between the speaker and the listener, then a compliment will have no any effect. And if you cut distinct connections in the neural network of the listener, no smile will occur on his face.

    The reductionistic approach is still very successful in biology and medicine. But it makes no sense to go below the level of ions and molecules (except in some special instances like energy transfer, molecular conformation changes, etc.). Our research on the physical mechanisms underlying the psychological events has just started.

    We are living in exciting times.

    • Stephan Schleim Reply | Permalink

      But nevertheless, this causal connection is based on a vast amount of purely physical events, i.e., causal relations.

      Perhaps in your dreams.

      If you equate "causal relation" and "physical event", then you simply beg the question (and ignore my text).

      You can’t escape from the material world. Without the causal relationships on the basal physical level, there were no any causal relationships on the higher levels of description (like psychology)

      How can you know? We often don't even know what causation "really" is; I suggested a working definition for "causal relation" in this text – and for this working definition your understanding of physical causation is mostly, if not completely, irrelevant.

      If you cut the physical connection between the speaker and the listener, then a compliment will have no any effect. And if you cut distinct connections in the neural network of the listener, no smile will occur on his face.

      And if I don't utter the compliment or if the listener does not listen, it will have no effect either. So what? You go from "X is necessary for Y" to "X must be the necessary and sufficient cause for Y" – this is a logical mistake.

      The reductionistic approach is still very successful in biology and medicine.

      No, the other way round: Just because scientists in biology and medicine, like in other disciplines, too, do not care much about reduction they are so successful.

      Our research on the physical mechanisms underlying the psychological events has just started.

      I don't know – some doctors tried to treat headache with electrical stimulation (by means of electrical fish, for example), thousands of years ago.

      We are living in exciting times.

      I agree – but probably this is a trivial insight, as every generation may have thought that they are living in exciting times; during some online discussions I actually get the feeling that our times can be quite boring. ;-)

  3. Balanus Reply | Permalink

    @Stephan

    Thank you for your detailed reply.

    » If you equate "causal relation" and "physical event", then you simply beg the question (and ignore my text).«

    Hmm, I think, I do not beg the question because I do not »equate "causal relation" and "physical event"«. What I’m doing is to name the prerequisite for psychological causal influences, namely the physical (causal) connection of the interacting subjects.

    »And if I don't utter the compliment or if the listener does not listen, it will have no effect either.«

    Yes, of course, if you don’t initiate a physical causal chain, then there will be no psychological effect.

    So you agree that physical causal chains are mandatory for psychological causes?

    When I wrote: »The reductionistic approach is still very successful in biology and medicine«, I had the ontological and methodological reduction in mind. Without this reductionistic approach you would know absolutely nothing about hemoglobin, nerve cells…

    »I don't know – some doctors tried to treat headache with electrical stimulation (by means of electrical fish, for example), thousands of years ago.«

    At that time, the soul still resided in the vesicles of the brain.

  4. Stephan Schleim Reply | Permalink

    Perhaps you do not think that you "equate 'causal relation' and 'physical event'", but this is what you wrote when you referred to "a vast amount of purely physical events, i.e., causal relations." In this statement you claimed that causal relations are a kind of (or a subclass of) purely physical events.

    Thus you are begging a question by claiming that there can be only physical causal relations.

    So you agree that physical causal chains are mandatory for psychological causes?

    I do not deny that there are physical happenings when I utter a compliment; and I do not deny that some such physical happenings are necessary for my uttering that compliment.

    What I say is that when I utter a compliment, this sometimes causes a smile to happen; to understand this causal relation in the sense of explaining why compliments sometimes are related to smiles I do not need much knowledge of the physical happenings – this is what I actually observe frequently when meeting people on the dance floor and paying them a compliment for their dressing and/or dancing style. And you know what? I don't need to think about physical happenings at all.

    • Balanus Reply | Permalink

      @Stephan

      »What I say is that when I utter a compliment, this sometimes causes a smile to happen; to understand this causal relation in the sense of explaining why compliments sometimes are related to smiles I do not need much knowledge of the physical happenings […]«

      Yes, of course not.

      But perhaps someone wants to know, what’s happening at the physical level when such psychological interactions occur. And then and only then we need presumably not more than the known particles and forces---as Carroll has stated (even though we surely need not go down to level of particle physics).

      • Stephan Schleim Reply | Permalink

        But perhaps someone wants to know, what’s happening at the physical level when such psychological interactions occur.

        Yes, right, just as you can investigate virtually every question scientifically and with more detail.

        But the important question in this context is whether this purely physical explanation of the causal relation between compliment and smile would tell us anything essentially new about why compliments and smiles are in this relation, what we already can explain sufficiently psychologically.

        And then and only then we need presumably not more than the known particles and forces---as Carroll has stated (even though we surely need not go down to level of particle physics).

        Right, again, but a scientist might then still like to ask what the underlying mechanisms of the protons, electrons, and neutrons and the forces constituting the smile are. :-)

  5. Markus Dahlem Reply | Permalink

    This post is more interesting -- to my mind. The example with the compliment, that causes someone to feel better, reminds us--us, who think in terms of physics--that the (twisted and complicated) state space configuration should be more emphasized when we highlight our simple truth that all is based on a few particles and forces.

    I don't like to go into this again. But even as someone who likes to think in such reductionist terms, I, of course, do not think that all the other academic disciplines will one day be replaced. Just that they build on physics in very clear ways that become, however, too fast too complex to follow.

    • Stephan Schleim Reply | Permalink

      Nice statement, Markus; I had the pleasure to participate in a presentation by Klaus Mainzer, professor for the philosophy of science at the Technical University Munich, on complexity and how to cope with it in science. Very convincing and impressive, though he was a bit more optimistic than I find warranted. :-)

      Anyway, he has an interesting book forthcoming 2013 on this issue. I am likely to blog here on it once I find the time reading it.

      Merry Christmas!

      • Markus Dahlem Reply | Permalink

        Merry Christmas, Stephan! Looking forward to what Klaus Mainzer has to say.

        And best wishes for a happy and prosperous New Year 2013!

  6. Chrys Reply | Permalink

    German speakers here may also be interested in accessing the recent NZZ article by Felix Hasler, author of 'Neuromythologie – Eine Streitschrift gegen die Deutungsmacht der Hirnforschung'. [NZZ am Sonntag, 7 Oct 2012]

  7. Trajan Reply | Permalink

    "Does our incapability to formulate my compliment and your smile in physical language mean that they do not exist?"
    It means that we don't yet understand how the brain creates meaning and understands the world.
    This is a good example for circular reasoning: The brain creates meaning which we don't understand, and under the assumption that one can't - in principle - explain the brain one can't - in principle - explain the brain. It begs the question because it assumes that a KI which can identify meaning by itself isn't possible.

    • Stephan Schleim Reply | Permalink

      This is a good example for a misunderstood question:

      We understand a lot about how we create meaning; but if we only look at the brain, or only at electrons, protons, and neutrons, we do not understand anything about meaning. That's one of the points of the series and no circular inference.

      Whether there will ever be an AI that identifies meaning – and what this means – and whether we will then be able to understand this AI and how it does this is yet another question.

      There is no circularity; there is only your misunderstanding. If you re-read my quote then you understand, I hope, that this is a statement about the existence of meaning and not about the question whether we understand it or not in terms of neuroscience or physics.

      • Trajan Reply | Permalink

        “if we only look at the brain, or only at electrons, protons, and neutrons, we do not understand anything about meaning.”
        Yes, but the question isn't if we can already understand meaning in physical terms, but if it's in principle possible to do so.
        One could also ask if the brain creates meaning through physical mechanics, or through some sort of paranormal “soul”.
        Since we don't understand the physical mechanics in the brain yet (not even close), there's no way to know if our inability to describe meaning in physical terms is because of our lack of knowledge of the physical brain, or because there is this paranormal “soul-thingy” which creates meaning.
        So we use Occam's razor and assume the easiest version: That we simply don't understand meaning because we don't understand the physical brain.

        “There is no circularity; there is only your misunderstanding. If you re-read my quote then you understand, I hope, that this is a statement about the existence of meaning”
        I'm not so sure if one can simply say that meaning just “exists”. It's something completely subjective, and differs from person to person. Even if you take one single person: His understanding of the world could be inconsistent. Let's take the example of the compliment: I could misunderstand you, or it's even possible that I think that you are only kidding me.
        Concerning the circular reasoning: I don't want to say the meaning doesn't exist. But the question is whether we can find a physical (or mathematical) description. If the brain creates meaning through physical mechanism, we CAN find a physical description of meaning. If it's some sort of “soul”, it will probably be impossible.
        All we know is that – at the moment – we don't know any such description. But we don't know if this will change in the future!

        • Stephan Schleim Reply | Permalink

          Yes, but the question isn't if we can already understand meaning in physical terms, but if it's in principle possible to do so.

          That's your question – so how do you argue that it is in principle possible to understand meaning in terms of electrons, protons, and neutrons?

          One could also ask if the brain creates meaning through physical mechanics, or through some sort of paranormal “soul”.

          One could also start out with the facts instead of metaphysical speculation – and observe that people (sometimes) communicate by means of language and that they (sometimes) understand each other when they understand the meaning of the words the other one utters or writes.

          Since we don't understand the physical mechanics in the brain yet (not even close), there's no way to know if our inability to describe meaning in physical terms is because of our lack of knowledge of the physical brain, or because there is this paranormal “soul-thingy” which creates meaning.

          How do you know that "physical mechanics" will be the appropriate level of description?

          But I agree that we cannot decide yet whether it is in principle possible to give a purely physical description of meaning; but you seem to think that it is in principle possible – so why do you think so? (See above, same question)

          So we use Occam's razor and assume the easiest version: That we simply don't understand meaning because we don't understand the physical brain.

          That's a logical fallacy and quite a funny and, at the same time, dangerous one:

          Occam's Razor is a (philosophical) instrument to be used in the situation where two theories T1 and T2 explain the observations equally well, but one of the two is more parsimonious in terms of proposed entities.

          But this is clearly not the situation we are discussing: Either we don't have a convincing theory of meaning at all, then which one do you want to eliminate? Or we actually have one that explains a lot (e.g. a cultural or linguistic account of meaning) and one that explains nothing (e.g. a physicalistic one). And you want to eliminate the theories with much more explanatory power with Occam's Razor? That's ridiculous!

          I'm not so sure if one can simply say that meaning just “exists”.

          How do you know something exists? I described an account in my series and according to this account (a pragmatical account) meaning does exist.

          If the brain creates meaning through physical mechanism, we CAN find a physical description of meaning.

          That's a logical fallacy: From the fact that something is physical (metaphysical claim) it does not follow that we can find a physical description of it (epistemic claim).

          I am quite certain that one could also use Gödel's incompleteness theorems to argue that we already know that there will not be physical descriptions for everything that is physical, but I rather leave this argument for the mathematical philosophers; or a moment with more leisure time.

          But all of this, again, gets us back to the question: Why do you think that it is in principle possible to give a purely physical description of meaning?

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