This is the second part – of four – of the talk ‘The Science Delusion’.


4. Physicalism: Not Dualism

A central topic of this talk is physicalism. But what is physicalism? To answer that, I will offer a crude comparison with dualism that is simplistic but sufficient to illustrate the idea.

Dualism (by which I mean Cartesian dualism) is the belief that there are essentially two types of ‘stuff’ – mind and matter (C.S. Lewis called them ‘Reason’ and ‘Nature’, respectively but they are essentially the same two types of ‘stuff’). Moral agency can be placed on all minds, equally – minds being the seat of free will. However, the great problem with dualism is how to rationalize how the separate domains of mind and matter interact with one another (Descartes notoriously located the point of contact at the pineal gland within the brain).

By contrast, physicalism is the belief that there is only matter. Unlike Christian doctrines that states that ‘we are in the world but not of the world’, physicalism leaves us wholly in the world and of the world. Dualism offers the prospect of mind surviving the destruction of the matter whereas physicalism seems to close the door to that possibility. The dualist’s problem of how mind and matter interact does not arise; the problem of mind is then shifted to the question of how consciousness arises out of the purely physical. And there seems to be a problem of fitting ‘free will’ into a purely physical world.


Physicalism (Realism / Materialism / Naturalism?)

Religion: Traditional Christian

Science: Atheist

Separate Mind and Matter (‘Reason’ and ‘Nature’)

Just physical stuff (matter/energy)

“In the world but not of the world”

(wholly in the world and of the world)

Joins at ?!


Free will & responsibility

determinism; none?!

Mind is conscious

Matter is conscious?!

Mind can outlive Matter

No life after death

Note that physicalism has previously been called ‘materialism’ (Sheldrake used that term), and before that, ‘realism’. There are everyday connotations associated with ‘materialistic’ and ‘realistic’ so I prefer to use the term physicalism.

5. Physicalism: Not Naturalism

For some, the term ‘naturalism’ is also synonymous with physicalism. But here I want to make a distinction – not because I think this is how these terms should be used, but in order to emphasize a particular point about physicalism.

And to do this, I will provide another simplistic dichotomy – that between two disciplines within Cognitive Science – Psychology and Neuroscience.

Psychology Neuroscience
Naturalistic but not necessarily physicalist Naturalistic and physicalist
Can be compatible with dualism Incompatible with dualism
Black box:behaviourist Looking insidehow physically constituted?
mechanistic,empirical,… ‘the properties of larger objects are determined by those of their physical parts’
top-down bottom up

Psychology has been around for well over 100 years. Neuroscience has only become a distinct academic discipline in the last 25 years or thereabouts. Psychology has had to fit in with our knowledge of the mind – given that we knew so little about it – and taken a ‘black box’ approach to the brain: since it was premature to speculate about how the brain works, we don’t look inside it but make scientific observations of the behaviour of the whole as observed from outside.

Naturalism is contrast with the supernatural; naturalism denies the supernatural. Now, it seems strange to think there is anything supernatural about a single person or a group of people. ‘Supernatural’ seems to refer to spirits that could be located in space, or God, outside of it, but not to ourselves, even if we see ourselves as distinct Mind plus Matter. I want to claim that Naturalism, and Psychology are potentially compatible with Dualism because they can be behaviourist.

The Behaviourism of Psychology is not concerned with what is inside the being, merely the externally-available (scientifically verifiable) observations – its behaviour. But Neuroscience is specifically interested in what is inside the brain physically, understanding how smaller physical elements combine to produce the observable phenomena of the whole. Progress in Neuroscience has become possible largely as a result of improvements in instruments to see inside the brain – first with EEG and more recently with PET and MRI scanning.

The point I want to emphasize here is that physicalism is necessarily reductionist and neuroscience is a physicalist science. Ultimately, everything can be reduced to – well, physics. Recall how Francis Crick famously said we’re ‘nothing but a pack of neurons’ – but that was for shock value. And this does not mean physics is superior to any other science; science is not just about reduction.


6. Layers of Explanation

There is a natural hierarchy in the natural sciences: biology sits on top of chemistry and chemistry sits on top of physics. We can explain biological behaviour in biological terms but, in principle, we could reduce biology to chemistry: we could run simulations at the chemical level that should reproduce the biological behaviour. This does not mean that biology is just chemistry. It does not mean that biology can just be reduced to chemistry. Rather than ‘reducing’, philosophers of science talk of biology ‘supervening’ on chemistry – which can be put simplistically as ‘sitting on top of’, as I said earlier.

A simulation of a human brain in a supercomputer that models the brain at the level of segments of neurons (such as being the ultimate goal of the Human Brain Project) may (at some point in the not-so-far future) produce behaviour commensurate with real brains but such a simulation would not have no explanatory value. It does, however, provide a very good reference from which explanations can be derived. So in science, we need abstraction (the generation of higher-level approximations from low-level behaviour) as well as reduction (the generation of low-level foundations for high-level theories.

Traditionally within science, there has been a disconnect between the social sciences and the natural sciences – the traditional domains of mind and matter respectively. Any science can be studied within either a behavioural (non-reductionist) framework or a physicalist (reductionist) framework. (Although, the very lowest level must remain purely behavioural until a theory about an even lower level can prove itself useful.) Neuroscience, the adolescent upstart within science, essentially takes a physicalist approach to try to eventually connect the social sciences with the natural sciences.

Of the main frontiers of science, physics operates at the hugely-large (cosmology) and the tinily-small (particle physics) which is of academic interest for an understanding of the world around us but has little impact on our everyday lives. But connecting mind to matter is something at the human scale, with human consequences.


‘mind’ social sciences sociology/economics ethology / sociobiology
‘matter’ biology neuroscience physiology / anatomy
cell biology
molecular biology
chemistry organic chemistry
molecular chemistry
physics atomic physics
quantum physics


7. The Brain: Physically and Pragmatically

The last talk ‘What I Know and Why I Know It’ looked at how the brain works in physicalist terms, breaking the brain down to a hierarchy (in very simplistic terms; more accurately, a jumbled mess with some semblance of hierarchy) of model-based predictors. This was Karl Friston’s ‘variational free energy’ theory – the beginnings of an overarching ‘universal’ theory of the brain. It then linked that with ideas in the philosophy of knowledge – epistemology. Specifically, it created a close association between Friston’s theory and Susan Haack’s Foundherentist theory of knowledge in which the brain builds up knowledge through a balancing act between internal coherence and correspondence with the external environment.

unified_model2 The diagram to the right has been presented before. At each level in the hierarchy maintains an internal model of what it ‘sees’ looking downwards. For example, level H ‘sees’ level G below it and maintains an internal model of it, G’. It continually updates the model and acts on the basis of its predictions.

The talk presented the acquisition of knowledge by the brain as an evolutionary growth of the connectome  (the entire network of neurons within the brain). It finished by looking at cognitive biases and how it is difficult to change established patterns in the brain, which is most difficult with the most general and longest entrenched views – out worldviews; our belief systems. Cognitive biases are practical difficulties when it comes to enforcing how we should know.

This talk continues the two themes of that talk – physicalism and pragmatism. In short, it takes a pragmatic approach to physicalism.


8. Slowly Shifting Worldviews

Because of our cognitive biases, it can take many generations for the predominant worldview to change. One person’s connectome grows in one way but, once ‘established’ (like a shrub), it is difficult to change substantially. But a person’s offspring’s connectome can adapt itself to the modified culture in a less encumbered way.

Since Descartes rationalized dualism 350 years ago, I would claim there has been a gradual shift towards physicalism:

  •          As a general populace, we have changed from a monolithic Christian society to one I would describe as dualist – belief in a ‘spirit’ of some form without adherence to a conventional religion is widespread. Into the future, I would extrapolate to increasing physicalism (atheism) although there is nothing inevitable (‘progressive’ historicist) about this. (2011 U.K. census results: 60% Christian, 25% no religion, compared with 71% and 14% respectively in the 2001 census.)
  •          Intellectuals within society have changed from rationalizing dualism, through defences of dualism to outright rejection of it. Dualists in philosophy, psychology and neuroscience departments are now the rare exception (see this survey of philosophers’ opinions).
  •          The view of the world about us offered by science has changed from a simple clockwork-like mechanical (Newtonian) one in which life forms inhabit to a Gaia-esque one in which life emerges in all its (Darwinian) variety.
  •          That cold simple worldview of 350 years ago did not require much explanation. But then, there was not much opportunity to gain an education in order to understand back then anyway. Nowadays in contrast, we have benefited from universal education that has provided us with a scientific understanding of the world about us (to some degree) within a wider educational framework that is tacitly dualist. That is the best established position that can be currently achieved.
  •          Extrapolating into the future, we may have a more physicalist worldview. But that might require an education not available to us in our youth. We might need to re-educate ourselves – in rather exotic study topics such as neuroscience and systems science which will just be seen as normal to our grandchildren.


c. 1650 c. 1850 c. 1950 c. 2050
Christian Christian dualist (towards) physicalist?
Rene Descartes Henri Bergson Gilbert Ryle
Isaac Newton Charles Darwin Crick / Watson
minimal education becoming institutionalized scientific / implicit dualism scientific: neuroscience

9. A Suitable Home

I feel that there is an exasperation among atheists: why is it that, 150 years since Darwin’s ‘Origin of Species’, the majority of people have not abandoned religion? Why don’t they ‘get it’? It is as though the choice – presented here between dualism and physicalism – were a simple one. But I think they have underestimated the strengths of dualism compared with present-day physicalism in providing a complete worldview. As already noted, physicalism does not yet provide the answers to many important questions which result when taking the mind domain away from dualism to leave physicalism. It has too many holes which need plugging. Most significantly, just how does consciousness arise from (ultimately) just physics?

Dualism: structurally flawed

I want to make an analogy between the worldview we choose for ourselves (inasmuch as it is a choice) and the home we live in. The question is “In which house would you choose to live?” The problem is that we currently fall between two worldviews (without making the absurd choice of living halfway between the two houses, out on the street):

  •          Dualism is like a comfortable house of a few hundred years old. The windows are a bit draughty and the plumbing is a bit primitive. But more significantly, it is suffering from a huge subsidence crack down one entire wall of the house. (That subsidence crack represents the failure to adequately connect the domains of mind and matter.)
  •          Physicalism is like a brand new house designed with all modern conveniences, but unfortunately it is still under construction, without any doors and windows in it yet.

Whilst we may be able to see that the brand new house will be an attractive proposition when it is completed, it is not currently. Some may envisage the completed house as being like the architect’s models – stark and devoid of the cosy charm of their current abode.

Physicalism: still under construction

All too often, atheists seem to be hectoring and ridiculing the religious. Sneering. The approach is like shouting ‘go and live in that [unfinished] house there’ whilst you pull a few more bricks out from the huge crack in their wall. A more constructive approach would be to finish the construction of that unfinished house and put some pictures on the walls – to provide a complete worldview that might then compete more favourably with dualism.

(At this juncture, some might point out that physicalism is not like a new house at all as it has a rather long history dating back to Lucretius and further beyond that to Democritus. But a satisfactory account of how at least the behaviour of minds supervenes on the physical has been a very distant prospect. However, progress in recent years means that such an account is now a ‘possibly within my lifetime’ prospect.)


(To be continued. Next part: Methodological Science.)



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2 Responses to Physicalism

  1. Wyrd Smythe says:

    I think my view is more along the lines of seeing two old houses, both terribly flawed. My guesses, hopes and belief about the nature of reality cause me to choose one more than the other, but I’m very aware of how flawed both houses are.

    It’s not surprising that, in a world that places a high value on the immediate physicality of technology, and which has an uncertain relationship with prayer or miracles, and perhaps which has become jaded and lost its sense of wonder and curiosity, we increasingly prefer the hi-tech house. I mean, the wi-fi alone makes it a win, right? 🙂

    The problem I see with a clockwork universe is, what exactly are the ethics of a clock?

  2. Pingback: Ethical Physicalism | Headbirths

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