Introduction

In order for the causal closure argument to be devastating to dualism, two conditions need to be met:

(1)    The Causal Closure Principle is true

(2)    If true, the Causal Closure Principle undermines all feasible forms of dualism

In this essay, I argue that the Causal Closure Argument is not devastating to dualism. I do this by demonstrating that (1) is not necessarily true. At the very least I hope to prove that the steadfast commitment to (1) by the majority of philosophers and scientists is unjustified (section 1). I will then defend interactionism from the other arguments that are frequently thrown at it (section 2). 

Section One – Why we shouldn’t claim with certainty that the Causal Closure Principle is true

The Causal Closure Principle (CCP) states that every physical event only has physical causes – and hence that every physical event is explicable purely in terms of physical causes.

I can think of three reasons why a great deal of philosophers and physicists take CCP as given.

The first reason is based on an inductive assumption appealing to the history of science. A huge variety of physical phenomena have been explained (if not fully, then at least to a great extent) in terms of physical causes only. Moreover, in most of these cases, it seems that there is no reason why anything other than physical causes should feature in our explanations. From the motion of rocks falling down cliffs, to the motion of planets orbiting stars, it seems obvious that only physical causes are responsible. The vast array of physical phenomena that have been partially explained (and that in principle seem fully explicable) in terms of purely physical causes, is undoubtedly one factor in the wide-scale acceptance of the causal closure principle.  

This is not a good reason to believe that every physical event is explicable in terms of purely physical causes, and hence it’s not a good reason to believe in CCP. The dualist believes that there are good independent reasons to believe that phenomenal states are irreducible to physical states, and we all believe that phenomenal states are closely associated with the brain. Assuming these two points, we have reason to believe that certain brain processes might buck the trend of all the other physical phenomena.  In other words, we cannot make the inductive leap from i) the majority of physical phenomena have purely physical causes to ii) all physical phenomena have physical causes. We cannot make this leap because we’ve assumed that there is an ontological divide between the physical and mental, and we’ve assumed that the mind is associated with the brain. It could be reasonably argued that the two things that we have the least physical understanding of are dark matter and the brain. Given our limited understanding of the brain – demonstrated by the fact that we cannot give an anywhere near complete picture of brain processes purely in terms of physical causes, and the two assumptions a) that the mind is ontologically distinct and b) that the mind is ‘housed’ in the brain, we are unjustified in making the inductive leap from i) to ii) – we have enough reason to believe that certain brain processes are left out of the inductive blanket. Importantly, to make such an induction is to beg the question against interactionism.

The second reason why CCP is taken as given by many is because science has progressed, and continues to progress, on the assumption of materialism. Materialism is the dominant viewpoint amongst scientists and philosophers. To be a materialist is to believe that there are only physical phenomena (and hence mental phenomena are reducible to physical processes); obviously if you believe only in physical phenomena, then you must hold that all physical phenomena have purely physical causes.

It’s beyond the scope of this essay to argue for dualism; but for the purposes of this essay we cannot simply assume the truth of materialism. As a result, this second reason for believing in CCP is irrelevant, and it also begs the question against dualism (unless additional arguments are provided for materialism).

The third reason for believing in CCP is that it is taken to conflict with a fundamental truth of science: the Principle of the Conservation of Energy (PCE) – this is the argument most commonly used against interactionism. It is by far the strongest argument against interactionism because it doesn’t beg the question against dualism or interactionism, which the previous two arguments do to some extent. The rest of this section of the essay will be dedicated to defending interactionism from the charge that it violates PCE. A closely related argument is that interactionism violates the Principle of the Conservation of Linear Momentum (PCM).

Two ways of formulating PCE are provided by Robert Larmer. The first is: ‘energy is neither created nor destroyed.’ (he calls this ‘the strong’ version)1 The second is: ‘in a causally isolated system, the total energy level remains constant.’2 (he calls this the ‘weak’ version)

According to the first definition, the objection from PCE would be the following:

There are mind-brain interactions (i.e. interactionism is true)

Mind-brain interactions involve the creation or destruction of energy

Energy can neither be created nor destroyed

1, 2 , 3 conflict; we are certain of 2 and 3, hence 1 is false

(call this ‘argument 1’)

 

According to the second definition, the objection from PCE would be the following:

There are mind-brain interactions (i.e. interactionism is true)

In any causally isolated system, the total energy level remains constant

The physical world is a causally isolated system

Mind-brain interactions alter the energy level of the physical world

1,2,3,4 conflict, we are certain of 2,3,4, hence 1 is false

(Call this ‘argument 2’)

Robert Larmer argues that interactionism need not conflict with PCE as defined in the weak version. That is, the interactionist can maintain that the total energy level of a causally isolated system remains constant whilst also believing that there are mind-brain interactions that alter the energy level of the physical world. He can accept the truth of the weak definition whilst also believing in mind-brain interactions that alter the energy level of the physical world. He can do this simply by denying premise (3) of argument 2.

Importantly for Larmer, there is a great deal less experimental evidence in support of the weak version than of the strong version. Of course, it is true that there is no completely causally isolated system in the universe – the universe as a whole is presumably the only thing that is completely causally isolated. Nonetheless, within systems that are more or less causally isolated, energy has always proven to be more or less conserved. It is a perfectly sound inductive leap from this experimental evidence to the statement ‘if we could create a perfectly causally isolated system, energy will always be conserved in it.’

David Papineau notes that certain forces that were once considered non-conservative e.g. friction, have turned out in fact to be conservative. It seems on first appearance that friction might cause the deceleration of an object without any corresponding gain in energy; and hence it might seem prima facie to be non-conservative. However, in truth energy is conserved on the micro-level: heat energy is generated and this energy compensates for the loss of kinetic energy.3 Therefore, not only is there a great deal of experimental evidence supporting the weak version, but the weak version is also bolstered by the fact that all forces originally considered non-conservative have been proved otherwise. It would be very reasonable to make an inductive inference from all known forces to all forces.

Fortunately, as Larmer notes, the interactionist does not have to deny this body of evidence, and does not have to deny the truth of the weak version of PCE: ‘The interactionist, no less than his opponent, accepts the body of evidence which suggests that in an isolated system energy is conserved.’4 The interactionist simply denies that the physical world is a causally isolated system. There is certainly insufficient evidence to suggest that the brain is causally influenced only by itself, the rest of the body, and the material world, and not the non-material mind. Hence there is insufficient evidence to suggest that the physical world is a causally isolated system.

Larmer concludes by writing, ‘Interactionism conflicts not with the weak form of the Principle, the claim that in a causally isolated system, energy will be conserved, but with the strong form of the Principle, the claim that energy can neither be created nor destroyed.’ If there is good reason to believe the strong form of PCE, then Larmer is still in trouble. After all, in his version of interactionism, energy is created by the mind. I believe, however, that the evidence for the strong form of the principle is inconclusive. Indeed, Robins Collins actually argues that it can be shown not to apply to all physical interactions.5 He believes that General Relativity provides examples in which energy is not conserved; indeed, such non-conservation occurs whenever we include the effects of gravity. Collins writes ‘although gravitational fields and waves clearly causally influence material objects, their influence cannot be understood in terms of movement of energy through space.’6 Collins mentions the philosopher Hoefer who argues that energy is not conserved in the universe as a whole because it is not asymptotically flat’7. Collins even appeals to Einstein himself in defending his argument, writing, ‘Einstein was explicitly aware of the problems with PEC as early as 1916.’ 8

Sean Carroll argues along similar lines to Robins Collins. He says that energy is only conserved if we are talking about a region with time-translation invariance. A region with time-translation invariance is a region in which ‘the background on which particles and forces evolve, as well as the dynamical rules governing their motions, are fixed, not changing with time.’9

In other words, if space-time is completely still, then the energy of the universe is constant. However, our universe is not of this nature, and so there is no reason to think that the energy level of the universe should be conserved. Carroll notes that some scientists and philosophers will want to make certain definitional adjustments to preserve PCE. For example, they might say that gravitational fields contain negative energy and that this exactly cancels the energy that is gained by the matter. Carroll argues against this, noting that energy is generally taken to be something that has density, and ‘there is no such thing as the density of gravitational energy.’10 Second, he notes that the energy associated with curved space-time is not uniquely defined. Collins makes the same objection to such a move, writing, ‘this could not be correct since the total energy of the universe is undefined in GR.’11 Carroll concludes by writing, ‘I personally think it’s better to forget about the so-called “energy of the gravitational field” and just admit that energy is not conserved.’12

The clear objection here would be to say: ‘but if energy is not conserved, then why are perpetual motion machines impossible?’ Dennett writes, ‘the conservation of energy accounts for the physical impossibility of perpetual motion machines, and the same principle is apparently violated by dualism.’13 This is explained by the fact that on the earth and in places where conditions are earth-like, space-time is almost flat. Resultantly, energy is conserved in these conditions, and perpetual motion machines are impossible. Unless you could create a machine spanning across a vast region of curved space-time, perpetual motion machines are impossible. You cannot violate energy conservation in normal conditions, but this does not mean that PCE is true in all conditions. It might here be objected that mind-brain interactions take place on earth where space-time is flat. However, the point being made is not that the mind exploits curvatures in space-time; rather it is that because GR conflicts with PCE, there is reason to think that PCE is not universally applicable.

Collins also alludes to the phenomena of Quantum entanglement. He uses Quantum entanglement as an example in which events have law-like correlations without energy or momentum exchange. These are correlations between events that are space-like separated (this means that they are too spatially distant to be causally related (the causal link would have to travel faster than light, which of course is impossible under special and general relativity)). In these examples, there cannot be an energy transfer between the two events because this would require a violation of one of the central tenets of Relativity. Moreover, Quantum Mechanics also predicts that the correlations occur without energy transfer. In other words, there are many examples in nature in which two events are connected but separated at such a distance that energy transfer between the two events is impossible (there may of course be more than two entangled particles). Collins notes that these are not just ‘some minor ‘technical exemption’ within physics, but pervasive throughout the whole microscopic world.’14 The relevance of quantum entanglement for interactionism is this: law-like correlations between events do not require a transfer of energy. Hence, law-like correlations between the mind and brain might not require a transfer of energy.

Quantum Entanglement is an established part of physical science. Interestingly, Einstein, Podolsky and Rosen published a paper attacking Quantum Theory on the grounds that it would allow for Quantum entanglement – a phenomenon that they regarded as impossible on the grounds of relativity and certain very understandable assumptions on the nature of causality.15 Later, this prediction of Quantum Mechanics was experimentally verified. Even with a limited understanding of Quantum Mechanics (and physics generally), it’s clear to me how Quantum Entanglement can be used by the interactionist. The anti-interactionist can only respond to these correlations by suggesting that they are the result of instantaneous transfers of energy. However, to make such an argument would require undermining a central principle of Relativity: the principle that nothing can travel faster than light.

We can conclude two things. First, the weaker formulation of PCE - that within any closed system, energy is conserved – is not violated by interactionism, so long as the physical world is not causally closed. To make the assumption that the physical world is causally closed is simply to beg the question against interactionism. Second, the stronger formulation – that energy is neither created nor destroyed – is, at most, in contradiction with modern physics, as argued by Robins Collins and Sean Carroll.  At the very least it is unsubstantiated, and it is certainly not necessitated by our currently accepted physical theories. Whether or not one accepts the arguments posed by Collins and Carroll against the strong version of PCE (conceivably a good physicist could offer a different but valid interpretation of GR and QM in which energy is conserved), one must accept that the strong version of PCE cannot be accepted without additional empirical evidence.

My final response to the objection from PCE is this: even if one is convinced of the strong version of PCE (one may have metaphysical reasons for believing in it, for example16), one can still accept interactionism. The mind as conceived by Descartes is something that creates energy that would otherwise not be there. Clearly this violates the strong version of PCE. However, one could have a very different account of interactionism. Perhaps mental states are responsible for redirecting physical energy rather than creating it. Certain neural processes are causally responsible for certain mental states. The firing of C-fibres, for example, is responsible for the feeling of pain. Perhaps this mental feeling then redirects energy into certain relevant motor neurons. Hence mental phenomena could act as ‘energy-redirectors.’ This version of interactionism would not violate the strong version of PCE because no energy would be created or destroyed.

C.D. Broad makes a similar response to the PCE objection. He suggests that the mind could alter the distribution and movement of energy in the brain without creating or destroying any energy. He provides the example of a pendulum: the motion of a weight at the end of a pendulum is clearly altered by the string attached to it (this can be proved simply by seeing the change in the weight’s motion when the string is cut). Broad argues that the mind could play a similar role to the string: it could redistribute energy without creating or destroying any.17 A more striking example is that of the earth. The earth’s motion is altered by the sun, but the sun is not providing the earth with any additional kinetic energy. If the mass of the sun were to suddenly vanish, then the earth would fly off in a tangent to its original ellipse without losing any energy.

Certain philosophers, such as Cornman, have attempted to block this move by suggesting that it would violate the Principle of the Conservation of Momentum (PCM). Averill and Keating show that these philosophers actually use a formulation of PCM that is stronger than what is warranted by physics and that begs the question against interactionism. Cornman writes, ‘any change of a system’s total linear-momentum requires that some net external physical force affect the system.’18 However, PCM does not require that the external force be physical. Averill and Keating accept the true formulation of PCM – ‘if the total external force is zero, the total linear momentum is conserved.’19 They also grant that if the mind exerts a force that moves a particle, then the total linear momentum of the brain is changed. However, they reject the claim that a force that can change the total linear momentum of the brain has to be physical. Such a claim is not entailed by PCE and it begs the question against interactionism.

In this section, I have demonstrated the following:

The argument for CCP based on an induction on the history of science fails because it begs the question against interactionism

The argument for CCP based on the truth of materialism fails because it begs the question against dualism

The argument for CCP on the basis of PCE fails because:

The weak version of PCE does not conflict with interactionism

Under one version of interactionism, the mind creates energy. Although this conflicts with the strong version of PCE, there is reason to think that the strong version of PCE does not universally apply, or at least we should accept that there is insufficient evidence for it

Even if we accept the strong version of PCE, we can still allow for interactionism if the mind has the role of redistributing, rather than creating, energy in the brain

 

Section 2: Other arguments against interactionism

Chalmers argues against interactionism by asserting that ‘we can always subtract the phenomenal component from any explanatory account, yielding a purely causal component.’20 He gives the example of ‘psychons’ – mental entities that are the seats of experience. He says that ‘we can imagine subtracting the phenomenal qualities of psychons, yielding a situation in which the causal dynamics are isomorphic.’21 This appeal to imagination is Chalmers’ weakest argument against interactionism. In truth, we cannot know a priori that we can remove the phenomenal properties from psychons and be left with a situation with the same causal dynamics. Chalmers is simply begging the question here and assuming what he is arguing for. If interactionism is true, then the phenomenal character of psychons is essential to their causal power and our causal explanation. Moreover, if these ‘psychons,’ instead of being ‘the seat of experience,’ were simply phenomenal character and nothing more, then by removing their phenomenal properties, we remove them entirely.

The problem of interactionism at its most basic can be summed up in this remark: ‘how could mind and brain possibly interact given that they are ontologically distinct? They are fundamentally different kinds of things, so how could they interact?’ Notably, we have no good theory of causation itself.22 Until we have a good theory of causation, there is no good reason to discount the possibility of mind-brain interaction. Chalmers makes the important point that we have similar issues of causation between physical particles. There may be no causal nexus between mind and brain, but ‘the same goes for any fundamental causal interactions, including those found in physics.’23 Chalmers concludes this point by saying ‘there is no need for a causal nexus distinct from the physical and mental properties themselves.’24

Finally, it is often argued that interactionism leaves no room for the mind to have any meaningful interaction with the brain. By ‘meaningful interaction,’ I mean interaction that is not random, and that has enough of an effect to be causally relevant to our behaviour. Some interactionists exploit a ‘quantum loophole,’ in which the seemingly random events in quantum physics are explained by the mind’s interaction with the physical realm. This may be so, but it leaves mind-brain interactions random. In a healthy body, the intention to raise an arm is followed by the raising of an arm. There is no randomness here; the action always follows from the intention in a predictable manner. Nonetheless, my account does not need to appeal to quantum randomness. Quantum entanglement, for example, could allow for predictable behaviour. I have also left open the possibility that the mind redistributes the energy of the brain. This redistribution of energy could allow for causally predictable and causally relevant behaviour, as in the redistribution of energy from c-fibres to motor neurons. This would also allow for certain neurons to fire that otherwise would not have fired, or certain neurons not to fire that otherwise would have.  An influence of this kind could be empirically validated or falsified, which is a strength rather than a weakness of the suggestion. Importantly, our understanding of the brain does not rule out such a possibility.

Conclusion

I have demonstrated that CCP is not devastating to dualism. I have done this by showing that we do not have good enough reason to accept CCP. In this sense, what I have done has been rather modest – I have not attempted to disprove CCP – I have simply demonstrated that there is no convincing reason to believe it, and hence that we should be agnostic with respect to it. I have also defended interactionism from the other major arguments directed at it. The reason for believing in interactionism is that it is very intuitive. It certainly seems as though the phenomenal state of pain causes me to remove my hand from the hot-plate, and hence it seems that the mind is causally efficacious. Finally, it should be noted that even if we accept CCP, we can still appeal to epiphenomenalism. Although it is a highly counter-intuitive position, a great deal of this counter-intuitiveness can be accounted for. Importantly, there are no arguments that show it to be incoherent or in conflict with anything we know. I will direct the reader to Chapter 5 of Chalmers’ The Conscious Mind, for a very good defence of epiphenomenalism. The word limit of this essay has prevented me from defending epiphenomenalism myself.

 

 

 

 

 

 

 

REFERENCES

A. Einstein, B. Podolsky, and N. Rosen (1935), Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?, American Physical Society

Carl Hoefer (2000), Energy Conservation in GTR, in Studies in History and Philosophy of Modern Physics, Vol. 31, Nº 2

Cornman (1999), A Nonreductive Identity Thesis about Mind and Body, in reason and Responsibility: Readings in some Basic Problems of Philosophy

David Chalmers (1996), The conscious Mind (In Search of a Fundamental Theory), Oxford University Press

David Chalmers (2002), Consciousness and its Place in Nature from Philosophy of Mind: Classical and Contemporary Readings, Oxford

Dennett (1991), Consciousness Explained, Penguin Science

Edward Averill and B.F.Keating (1981), Does Interactionism Violate a Law of Classical Physics?, Mind Vol. xc, 102-107

Laurence Goldstein (1980), The Reasons of a Materialist, The Royal Institute of Philosophy, Volume 55 / Issue 212

Robin Collins (2008), Modern Physics and the Energy-Conservation Objection to Mind-Body Dualism, American Philosophical Quarterly, Volume 45, Number 1

Robert Larmer (1986) Mind-Body Interaction and the Conservation of Energy, International Philosophical Quarterly, Vol. 26 pp. 277-285.

Papineau (2002), Thinking about consciousness, Oxford Press

Sean Carroll (February 22, 2010) Internet Blog, ( HYPERLINK "http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/" http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/)

William Lycan (2009), Giving Dualism its Due, University of North Carolina

1 Larmer (1986), p. 281

2 Ibid., p.281

3 Papineau (2002), 245

4 Larmer (1986), p.282

5 Robins Collins (2008), p.33

6 Ibid.(2008), p.36

7 Carl Hoefer (2000), p.194

8 Robins Collins (2008), p.37

9  HYPERLINK "http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved" http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved (2010)

10  HYPERLINK "http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved" http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved (2010)

11Robins Collins (2008), p.37

12  HYPERLINK "http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved" http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved (2010)

13 Dennett (1991), p.35

14 Robins Collins (2002), p.39

15 Einstein A, Podolsky B, Rosen N (1935)

16 Robins Collins, (2002), p.30

17 Kegan Paul (1925), ch.3 p.6

18 Cornman (1995), p.11

19 Goldstein (1980) p.5. quoted in Averill and Keating (1981) p.103

20 Chalmers (1996), p.158

21 Ibid. p.158

22 Lycan (2009), p.6

23 Chalmers (2002), p.30

24 Ibid., p.30

osophy, Volume 55 / Issue 212

Robin Collins (2008), Modern Physics and the Energy-Conservation Objection to Mind-Body Dualism, American Philosophical Quarterly, Volume 45, Number 1

Robert Larmer (1986) Mind-Body Interaction and the Conservation of Energy, International Philosophical Quarterly, Vol. 26 pp. 277-285.

Papineau (2002), Thinking about consciousness, Oxford Press

Sean Carroll (February 22, 2010) Internet Blog, ( HYPERLINK "http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/" http://www.preposterous