Intuitively, the mind can influence the physical world causally. However, it is difficult to understand how such causality does not require energy. According to dualists, who argue that the mind is not physical or reducible to physics (as discussed in works like Nagel's "What Is It Like to Be a Bat?", Jackson's "Mary's Room," and Chalmers' "the hard problem of consciousness"), there arises a question of how can dualists reconcile the causal function of the non-physical mind with the principle of causal closure, which is a fundamental principle in physics? This principle essentially states that all physical effects must have sufficient physical causes.

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    As far as I know energy conservation is not a law of general relativity. Moreover, "the principle of causal closure" is not a principle of physics. It is rather a metaphysical statement. Also can you tell what do you mean by saying that something is physical? And why do you think that the law of conservation of energy is inconsistent with mind being non-physical in you sense?
    – Slup
    Dec 31, 2019 at 12:09
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    And can you provide a reference for your claim (which is not the case in my opinion) that Chalmers or Nagel suggest that mind is causally closed? All these details would improve your question significantly.
    – Slup
    Dec 31, 2019 at 12:44
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    Does this answer your question? How do defenders of libertarian freewill reconcile it with constraints imposed by the laws of physics? One can design trigger-like mechanisms where mind's "interventions" are energy neutral.
    – Conifold
    Dec 31, 2019 at 13:38
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    I will answer your first question: the law of conservation of energy has nothing to do with causality of mind, except in the trivial sense that minds usually reside in brains, which are supported by metabolic processes which obey the laws of thermodynamics. Dec 31, 2019 at 17:35
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    mind is not separate from the material world. Stop eating for a few weeks and see what happens to your ability to think. Jan 1, 2020 at 12:22

3 Answers 3


The dualism of the authors you mentioned is perfectly compatible with the principle of conservation of energy. Though I am not directly answering your question, I may help with some misconceptions in your question.

According to dualists, the mind is not fully physical, but there are many types of dualism. Some of them are compatible with the principle of conservation of energy and some of them are not (i. e. Descartes). First, I will explain the ones that you cited, which are compatible.

What Thomas Nagel suggests in What Is It Like To Be A Bat? is that we need new concepts to understand the mind, that "the physical" and "the mental" may not be the best cathegories. This is because the subjective mind, the one that perceives qualitative phenomena (such as "what it is like" to be a bat), cannot be reduced to the objective and the physical.

The perception of qualitative, subjective phenomena (or qualia) is the core of the hard problem of consciousness. The hardest problem is not to explain how consciousness is produced (that can be explained in science), but how physical phenomena and consciousness' qualia are connected. Does Mary learn something the first time she perceives the quale of the color red? Frank Jackson says that she learns how others perceive the world, more than learning something in virtue of the quale itself.

But that isn't incompatible with the law of conservation of energy, as David Chalmers points out in The Conscious Mind, when he exemplified what he calls the "hard problem of consciousness" in his famous argument of philosophical zombies. Can you imagine a world physically identical to ours, where each neuron cell is connected to the same as in ours, where there is no consciousness? Where people do not perceive "red" or "rough" qualia? Where they are not conscious of their experience at all? Chalmers claims that you can imagine this world of "philosophical zombies" without modifying our knowledge of physics at all. Every law of physics applies exactly in the same way; the point is that conscious experience is not necessary. So, why does it even exist?! That's the hard problem of consciousness.

The idea of these dualists is that the mind cannot be reduced to the physical, but, as you can see, that does not imply that the principle of conservation of energy is violated. What they claim is that physicalism is not necessarily wrong, but incomplete. We cannot even draw a physical connection between physical causes and the qualia, we cannot even measure the qualia, so we wouldn't be able to measure the quantity of energy they take in a physical process. As long as qualia don't play a determinant role in the actions of an individual, there will be no problem. (Is it the "redness" of red [subjective] the thing that changes our mood, or is it the intensity of the light of this frequency [objective, physical]? Note that they are in different worlds. Physical is only affected by the physical.)

However, if you held a view in which there is a mental substance (res cogitans) not affected by physical laws, separated from a physical or material substance (res extensa) affected by physical laws, and that the first causes effects in the second, yes, there would be a problem with the principle of conservation of energy, because you would be introducing new energy in a world, "creating" energy. But then you'd have to hold that an important part of the mind is separated from the body, and not only its qualitative aspect.

I hope this will help


There is plenty of energy available in the brain to send neural signals to the muscles.

The mind does not contain energy at all. The mind only provides the control. The mind only decides where the energy is directed.



There are several mistaken assumptions in this question. Note that conservation of energy and causal closure are different assumptions. They are also both not absolute in physics.

Requesting dualists to explain how they deal with both is still a legitimate question.

Conservation of energy

As with other “laws” of physics, this is a regularity not a law. See this link on how all symmetries and therefore all “laws” in physics are spontaneously broken. https://www.pnas.org/doi/10.1073/pnas.93.25.14256 C of E is also known not to apply when there is a steep time gradient, such as during the early universe. It is also broken at conventional conditions with time crystals.

Note that cosmologists generally assume the C of E is violated. This is true of the inflation stage of the Big Bang, the creation of baby universes in Multiverse speculations, and the continuous creation of matter in free space in the Steady State model.

Physicists generally try to maintain conservation of something, even if energy isn’t conserved. Both Hoyle for Steady State theories and Sean Carroll for time near a singularity, plus multiple thinkers about cosmological inflation propose a different energy-like term, an energy prime, is conserved. So far none of these proposals has had their math actually work. See this discussion of the zero energy hypothesis about inflation. https://physics.stackexchange.com/questions/494408/the-zero-energy-hypothesis-and-its-consequences-for-particle-creation-and-dualis

Causal Closure of Physics

Physics is not causally closed, and cannot be. It is a science, and studies questions and challenges, and the answers discovered continually expand the scope of what we call physics. This is the core issue behind Hempel’s Dilemma, that one cannot define physicalism in a way that is not either clearly false, or allows things like Gods and Spirits to be physical. IF physics is a science, it is not closed, by definition.

Additionally, the global reductionism project has failed, and physicists have conceded that the other sciences do not reduce to physics. See the SEP on Scientific Reduction, section 5. Strong emergence and/or pluralism is what the failure of global reduction calls for. And we don’t have an emergence theory, nor a method to build a coherent pluralist worldview. We have already seen that physics as a science cannot be closed, but this empirical failure of reductionism also means physicalism cannot be closed either.

Additionally, no subset of the universe can be sufficiently isolated for causal closure to be applicable to it. AND as we saw above for cosmologists, universes are treated by theoretical physics as not being causally closed either, so there is no space, either a universe or any subset of it, that causal closure applies to.

But Dualists still have to answer the question

C of E is generally true. It’s exceptions are rare under conventional conditions, and are areas that call for physics study, and as a result dualists need to make proposals about how dualist interaction can be either understood, or further investigated in C of E terms.

Similarly, while causal closure is not an absolute, it is instead a massively useful starting assumption to allow physicists to characterize all sorts of problems. Dualists are responsible to answer how their proposals either could or do violate causal closure.

First answer, dualism uses quantum uncertainty and does not violate C of E, but does break causal closure

Because all potential quantum outcomes are within the probabilistic scope of physics, consciousness could potentially leverage this variable possibility range to achieve all sorts of different outcomes, without violating CofE.

This is the most common current view among spiritual dualists. It was spelled out explicitly by John Eccles in both The Self and Its Brain, and How the Self Controls Its Brain. It is also the approach spelled out by Richard Swinburne.

Eccles proposed that synapses are hyper sensitive to plausible ranges of quantum fluctuations and are therefore trigger able by souls that adjust that range within the CofE. Eccles’ calculation appears to be off by about 2 orders of magnitude, meaning souls would have to drive highly implausible quantum outcomes to trigger synapses.

If souls are able to tweak quantum probabilities to do no energy causation, then it is not clear how important the magnitude of the probability range is for Eccles mechanism to work. It would still be both possible and satisfy C of E even with wildly improbable quantum events.

A plausibility objection is that our conscious selves have a very difficult time understanding quantum mechanics, and brains in neural dynamics. So our souls tweaking QM multiple times continually to steer a brain’s neural pathways to have specific behaviors by opening synapses and steering it — requires a massive level of knowledge and coordination that our souls do not seem to exhibit the faintest capability to accomplish in an untutored state. AND this capability has to be in an unconscious part of the soul, that for TBD treasons does not share either QM or neural expertise with the conscious part.

I have not seen this plausibility issue addressed in my own reading of dualist thinkers. The lack of a plausibility argument on steering is not necessarily a fatal problem for this proposal, but it is a pretty big black mark.

Second Answer — Spirits are just able to create energy

This answer is that spirits are just interactive on the physical, violating both C of E and causal closure. Will is just able to influence the physical. Among spiritual dualists JP Moreland asserts this solution.

This answer makes most sense for theists, who hold that God created physics, and the universe, thru an act of will. Souls therefore could plausibly just exhibit the same sort of capability to a lesser degree.

This approach is very compatible with the libertarian free will thinking that is common among the non Muslim and non Calvinist theists, as the intrinsic agency of willing is basically treated as a fundamental property of souls/consciousness.

The plausibility of a soul being able to micro-control neurology unconsciously to get it to do what it wills, yet not share that knowledge with its conscious self is very similar to the problem noted above for answer 1. It is not as difficult as QM is not needed, just neurology. There is also an at least halfway plausible rationale that a created universe was MADE to be responsive to will intrinsically. This answer passes at least some credibility checks as it is then a defensible coherent view that this ability is sub rational, and therefore the details of how this skill works not being known by our consciousness is a coherent view.

Third Option — Souls and their causal powers are just part of an energy prime and physics prime, and energy prime is conserves and physics prime is closed

This option is to size upon both Hempel’s Dilemma and the way physicists propose higher level conservation when earlier physics models are refuted, and apply both to souls/consciousness. This is to basically break the presumption of differentness between mind and matter, and treat both as aspects of some higher interactive science. Karl Poppers 3 world emergent dualism falls into this general approach. His 3 world ontology is used as a basic ontological model, emergence rules for how consciousness emerged then need to be characterized, and then an investigation would need to be done on how mind and matter interaction happens and its rules.

This approach bears some similarities with neutral monism, but most neutral monist thinkers assume no interaction between mind and matter, and the dependence of both on some more real substance. Emergent dualism, in contrast, does not postulate some other “substance”, but just more science laws that guide emergence and interaction. Emergent dualism is far more intrinsically amenable to science investigation than the Russellian and pan-psychist neutral monisms.

This answer avoids the strong inclinations to spiritual dualism and theism in the prior two. It is also as noted open to scientific inquiry. However, there is almost no science answers to any of the potential science principles, leaving secular dualists with little to no substantial answers to “so what then” after declaring two meta phenomena (energy prime and closure prime) and two families of laws (emergence rules and mind/matter interaction).

As I am a practicing mystic, I also consider it in serious conflict with the evidences of discarnate entities. However, it is possible to recast spiritual dualism into this category if answer too, just without the emergence principles.


The problem of conflict of dualism with physics is not as hard as the questioner assumes, because physics is not inviolable. Additionally, dualists have offered three types of answers to how dualism interacts with physics, with varying degrees of test ability and plausibility. None of the three approaches is hopeless, and all 3 need more fleshing out.

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