Problems for Interactionist Dualism | AQA A-Level Philosophy
For Specification 7172
AQA A-Level Philosophy | Free Revision Notes
Estimated study time: 60 to 70 minutes
This Problems for Interactionist Dualism A-Level Philosophy revision lesson examines whether ontologically distinct mental and physical states can causally affect one another. Interactionist dualism claims that causation works in both directions, for example when a desire causes bodily movement or bodily impact causes pain. AQA specifies two major challenges: Elisabeth, Princess of Bohemia's conceptual interaction problem and the empirical interaction problem. These develop the issues surrounding substance dualism [Substance Dualism] by asking whether mind-body interaction is coherent and compatible with physical science.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Explain interactionist dualism.
Explain Elisabeth, Princess of Bohemia's conceptual interaction problem.
Explain why the non-extended nature of the Cartesian mind creates a problem for physical interaction.
Explain the empirical interaction problem and its connection with conservation of energy.
Distinguish the conceptual interaction problem from the empirical interaction problem.
Evaluate whether causal interaction between mental and physical substances is coherent.
Revision Notes 📚
Problems for Interactionist Dualism A-Level Philosophy Revision: the central issue
Interactionist dualism is a version of dualism that claims there is two-way causal interaction between mental and physical states.
Mental events can cause physical events.
Physical events can also cause mental events.
For example:
desire → bodily movement
and:
bodily impact → pain
This distinguishes interactionist dualism from epiphenomenalist dualism, which denies that mental states have physical effects.
The central question for this lesson is:
If the mental and physical are ontologically distinct, how can they causally interact?
AQA requires two problems:
the conceptual interaction problem
the empirical interaction problem
What is interactionist dualism?
Interactionist dualism accepts both:
a distinction between the mental and physical
genuine causal interaction between them
The interaction is two-way.
Mental to physical causation
A mental state may cause a physical event.
For example:
A desire leads to bodily movement.
The mental state has a causal effect upon the physical world.
Physical to mental causation
A physical event may cause a mental event.
For example:
A bodily impact causes pain.
The physical event has a causal effect upon the mental.
Interactionist dualism therefore proposes:
mental → physical
and:
physical → mental
Interactionist dualism and substance dualism
The issue is especially important for Cartesian Substance Dualism [Substance Dualism].
Descartes distinguishes:
mental substance, characterised by thought and lacking extension
physical substance, characterised by extension
Mind and body are therefore ontologically distinct.
The interactionist view nevertheless claims that these distinct substances causally affect each other.
This creates an obvious philosophical challenge:
If mind and body have fundamentally different natures, what makes causal interaction between them possible?
Elisabeth's objection targets precisely this point.
Elisabeth's Conceptual Interaction Problem
The basic objection
Elisabeth, Princess of Bohemia challenges Descartes' substance dualism by arguing that mind and body cannot interact in the way his theory requires.
Her reasoning begins with a conception of physical causation.
According to the objection, causation is conceptually constituted by contact between extended physical bodies.
But Descartes denies that the mind is:
extended
a physical body
Therefore, the mind cannot make physical contact with the body.
If it cannot make contact with the body, Elisabeth argues, it cannot causally affect the body.
Reconstructing Elisabeth's argument
The reasoning can be presented step by step.
Premise 1: Physical causation requires contact
The conceptual interaction problem starts from the idea that causal interaction between bodies involves contact between extended physical things.
So if one body moves another, the causal relationship depends upon the relevant physical relationship between them.
Premise 2: The Cartesian mind is not extended
According to Cartesian substance dualism, the mind is essentially a thinking rather than extended substance.
The body is extended.
The mind is not.
Premise 3: A non-extended mind cannot be in physical contact with the body
Because the mind is not an extended physical thing, it cannot stand in the ordinary spatial relationship required for bodily contact.
AQA's terminology puts the point strongly: if minds are not extended physical bodies, they cannot be in contact with or even in proximity to bodies.
Conclusion: mind and body cannot causally interact
If:
causation requires contact between extended things
the mind is not extended
then:
the mind cannot causally interact with the physical body.
This directly threatens interactionist dualism.
Why this is a conceptual problem
The problem is called conceptual because it concerns whether the proposed interaction makes coherent sense given Descartes' own account of mind and body.
It is not initially asking:
"Have scientists observed mind-body interaction?"
Instead it asks:
How could the two substances possibly enter into the kind of causal relationship Descartes proposes?
The apparent contradiction comes from combining:
mind is non-extended
with:
mind physically affects an extended body.
Descartes' distinction creates the problem
There is an important tension within Cartesian dualism.
The features that make mind and body distinct are also what appear to make interaction difficult to explain.
From Substance Dualism [Substance Dualism]:
Mind = thought, non-extension
Body = physical extension
But interactionist dualism then needs:
non-extended mind → extended body
Elisabeth's challenge is that the very distinction used to establish dualism appears to undermine the causal relationship the theory requires.
Why mental-to-physical causation is especially important
Interactionist dualism claims that mental states genuinely affect physical states.
For example:
I desire to move my arm.
My arm moves.
The interactionist treats the mental desire as causally relevant to the bodily movement.
Elisabeth asks how something non-extended could produce this physical change.
If causal influence requires the types of relations found between extended bodies, then the non-physical mind appears unable to play the required causal role.
Physical-to-mental causation
The interaction also operates in the other direction.
For example:
bodily impact → pain
The interactionist claims that a physical event can produce a mental event.
This creates the same general problem from the opposite direction.
If mental substance is fundamentally non-physical, how does a physical event cross the apparent ontological divide and cause a mental state?
Interactionist dualism therefore needs to make sense of both directions of causal interaction.
Evaluating Elisabeth's Conceptual Interaction Problem
Strength: it uses dualism's own distinctions against it
The objection is powerful because it begins with characteristics accepted by Cartesian substance dualism.
Descartes claims that:
body is extended
mind is non-extended
Elisabeth then asks how something non-extended can interact causally with something extended.
The objection therefore does not need to deny immediately that mind exists.
Instead, it asks whether Descartes' own account leaves interaction intelligible.
The interactionist can challenge the first premise
A possible response is to question the claim:
All causation must involve contact between extended physical bodies.
Elisabeth's conclusion follows only if this conception of causation is correct.
An interactionist can therefore argue:
Even if mind is non-extended, it does not automatically follow that it is causally powerless.
The key question becomes whether Elisabeth has established that physical contact is a necessary condition of all causation.
Why this response matters
The argument has the structure:
Causal interaction requires contact.
A non-extended mind cannot make contact.
Therefore, a non-extended mind cannot causally interact.
If Premise 1 is denied, the conclusion does not follow.
So the conceptual interaction problem places a burden on the interactionist to explain an alternative model of causation.
However, simply saying:
"The mind somehow causes the body"
does not solve the problem.
A satisfactory interactionist account still needs to make the proposed causal relationship coherent.
Does lack of explanation prove impossibility?
Another evaluative question is whether:
we cannot explain how mind-body interaction occurs
entails:
mind-body interaction cannot occur.
These are not automatically the same claim.
Elisabeth's argument is strongest if the proposed interaction is not merely unexplained but conceptually incoherent.
If the interactionist can show that causal influence does not logically require two extended bodies making contact, the objection may establish an explanatory difficulty rather than outright impossibility.
The burden on interactionist dualism
Even if Elisabeth has not conclusively proved interaction impossible, her objection creates a significant burden.
Interactionist dualism cannot merely assert both:
mind and body are fundamentally distinct
and:
mind and body causally interact.
It needs an account of how these claims fit together.
That is why the conceptual interaction problem is more than a demand for additional detail.
It asks whether the basic causal picture is coherent at all.
The Empirical Interaction Problem
The basic objection
The empirical interaction problem approaches interactionist dualism from a different direction.
It argues that the dualist claim that a non-physical mind or mental state causes physical changes conflicts with empirical evidence or scientific theory.
AQA's subject-specific vocabulary gives the example of the Newtonian law concerning the conservation of energy.
The question is therefore:
Can a non-physical mind make a difference to physical events without conflicting with the physical principles governing those events?
Why this is an empirical problem
Unlike Elisabeth's objection, this issue is based on the relationship between interactionist dualism and our scientific understanding of the physical world.
The conceptual problem asks:
How can a non-extended mind make contact with an extended body?
The empirical problem asks:
Is mental-to-physical causation compatible with the empirical laws governing physical processes?
The two objections should therefore not be confused.
Conservation of energy
The empirical problem can be illustrated through the principle of conservation of energy, the example identified in AQA's terminology.
Interactionist dualism claims:
a non-physical mental event can cause a change in a physical system.
This raises a problem.
If the physical system is governed by conservation of energy, how does the non-physical mind introduce a causal change without conflicting with that physical account?
The concern can be expressed as:
If physical events are governed by physical conservation laws, where does non-physical causal influence fit?
Mental causation and physical change
Consider the interactionist example:
desire → bodily movement
The bodily movement is a physical event.
The interactionist claims that the mental desire makes a causal contribution to that event.
The empirical interaction problem asks whether introducing this non-physical cause is compatible with the scientific account of the physical process.
If physical theory already constrains how physical changes occur, an additional non-physical cause appears difficult to accommodate.
Reconstructing the empirical interaction problem
A simple reconstruction is:
Interactionist dualism claims that non-physical mental states cause physical changes.
Physical changes are governed by empirical physical laws and principles.
The proposed non-physical causal contribution appears to conflict with this scientific account, for example with conservation of energy.
Therefore, interactionist dualism faces an empirical problem explaining how non-physical mental causation can occur without contradicting physical theory.
Notice that this argument differs from Elisabeth's.
It does not begin with the concept of contact.
It begins with the apparent conflict between interactionism and empirical science.
Conceptual and Empirical Interaction Problems Compared
The distinction is worth learning precisely.
Conceptual interaction problem | Empirical interaction problem |
Associated with Elisabeth, Princess of Bohemia | Based on empirical evidence and scientific theory |
Challenges the coherence of interaction | Challenges the scientific compatibility of interaction |
Focuses on contact between extended bodies | Focuses on physical laws governing physical changes |
Mind is non-extended, so how can it make causal contact? | How can a non-physical cause alter physical events without conflict with physical theory? |
Conceptual objection | Empirical objection |
A high-quality answer should explain this difference rather than treating both as versions of "we do not know how mind and body interact".
Evaluating the Empirical Interaction Problem
Strength: it pressures mental-to-physical causation
The problem directly targets a central commitment of interactionist dualism.
If desires, intentions or other mental states genuinely cause bodily events, then the non-physical must make a difference to physical processes.
The empirical objection asks whether the physical world leaves room for such an additional causal influence.
This is especially significant because two-way interaction is what distinguishes interactionist dualism from Problems for Epiphenomenalist Dualism [Problems for Epiphenomenalist Dualism].
The interactionist can question what the empirical evidence establishes
The interactionist could respond that an empirical conflict must actually be demonstrated.
The argument cannot simply assume:
all physical events exclude non-physical causes.
It must show that the relevant empirical principles are genuinely incompatible with mental causation.
Therefore, the interactionist can ask whether conservation principles establish:
non-physical causation is impossible
or merely:
current physical descriptions do not include non-physical causes.
This is an important distinction when evaluating the force of the objection.
Conceptual possibility versus empirical compatibility
An interaction might be:
conceptually possible
but empirically problematic
These are different issues.
For example, suppose Elisabeth's conceptual objection failed because causal interaction does not necessarily require physical contact.
Interactionist dualism would still face the empirical question:
Can such interaction occur consistently with the physical laws governing bodies?
So answering one problem does not automatically answer the other.
Why the two objections reinforce each other
The interactionist therefore faces pressure from two directions.
Conceptual pressure
How can an unextended mind causally interact with an extended body?
Empirical pressure
How can a non-physical cause influence physical processes without conflicting with scientific theory?
Together, these objections demand both:
a coherent account of the interaction
an empirically compatible account of the interaction
Interactionist dualism needs both if it is to provide a satisfactory theory.
Is Interaction Between Mental and Physical Substances Coherent?
Case against interactionist dualism
The case against the theory can be organised as follows.
First, Cartesian dualism deliberately makes mind fundamentally different from body.
The mind is non-extended.
The body is extended.
Elisabeth argues that this prevents the sort of contact required for causation.
Second, if the interactionist claims that the non-physical mind nevertheless changes physical events, the empirical problem asks how this fits with physical conservation laws.
The theory therefore appears caught between two claims:
mind is genuinely non-physical
and:
mind genuinely causes physical change.
The stronger the distinction between mental and physical substance becomes, the harder their causal interaction may be to explain.
Case available to the interactionist
Interactionist dualism is not defeated merely by saying that interaction is difficult to explain.
The defender can challenge assumptions within both objections.
Against Elisabeth:
Why assume that all causation requires physical contact between extended things?
Against the empirical objection:
Has scientific theory actually established that non-physical causation is impossible, or does it simply describe physical processes in physical terms?
These responses do not automatically prove interactionism.
They show where the objections themselves need justification.
The importance of explanatory completeness
A theory can survive an objection logically while still face an explanatory weakness.
Suppose an interactionist says:
"Mind and body simply do interact."
This preserves the theory but provides little explanation of the causal mechanism.
The philosophical issue is therefore not just:
Can we state interactionist dualism without formal contradiction?
It is also:
Does it provide a coherent and adequate account of the causal relationship it claims exists?
Interactionism compared with epiphenomenalism
One response to interaction problems is to deny one direction of causation.
Epiphenomenalist dualism accepts that physical events can cause mental events but denies that mental states have physical effects.
This avoids the claim:
non-physical mental state → physical change
that generates much of the interaction problem.
However, epiphenomenalism faces its own serious objections.
These are examined in Problems for Epiphenomenalist Dualism [Problems for Epiphenomenalist Dualism], including:
introspective self-knowledge
the phenomenology of mental life and apparent psycho-physical causation
natural selection and evolution
Avoiding interaction therefore comes at a philosophical cost.
Interaction problems and Ryle
The previous lesson, Ryle's Category Mistake [Ryle's Category Mistake], raised a more fundamental criticism.
Ryle questions whether treating the mind as an additional substance is conceptually mistaken in the first place.
The interaction problems arise once a dualist accepts distinct mental and physical reality and then tries to explain their causal relationship.
This produces a useful sequence:
Ryle: Should we posit a separate mental substance at all?
Elisabeth: If we do, how could it interact with physical substance?
Empirical interaction problem: If it does interact, how is that compatible with physical science?
These are distinct but connected challenges.
A strong evaluation structure
For an extended answer, organise the issue around the two objections.
1. State interactionist dualism
Mental and physical states are ontologically distinct but causally interact in both directions.
2. Explain Elisabeth's conceptual objection
Causation is claimed to require contact between extended physical bodies.
The mind is non-extended.
Therefore, it cannot enter into the required causal relationship.
3. Evaluate Elisabeth's premise
Ask whether all causation really must involve such physical contact.
If that premise is unsupported, the argument does not establish impossibility.
However, the interactionist still owes an alternative account.
4. Explain the empirical problem
Non-physical mental causation appears to conflict with empirical physical theory, including conservation of energy.
5. Evaluate the empirical objection
Ask whether physical theory actually rules out non-physical causation or whether the conflict still needs to be established.
6. Reach a judgement
A good judgement should distinguish:
conceptual coherence
empirical compatibility
explanatory adequacy
Interactionism needs to perform well on all three.
What you need to be able to do in an examination
For this topic, you should be able to:
define interactionist dualism
explain its two-way account of mental and physical causation
give the examples of desires causing bodily movements and bodily impacts causing pain
explain Descartes' distinction between extended body and non-extended mind
reconstruct Elisabeth's conceptual interaction problem
explain why physical contact and extension matter to her objection
identify the premise an interactionist might challenge
define the empirical interaction problem
explain its relationship to physical evidence or scientific theory
identify conservation of energy as the specified example
distinguish conceptual from empirical objections
explain why answering one problem does not automatically answer the other
evaluate whether interactionist dualism provides a coherent account of mind-body causation
link the problem to Problems for Epiphenomenalist Dualism [Problems for Epiphenomenalist Dualism]
The central issue to remember is:
Interactionist dualism must explain how something ontologically distinct from the physical can nevertheless make a genuine causal difference to physical events.
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Interactionist dualism | A form of dualism holding that mental and physical states are ontologically distinct but causally interact in both directions. | Define the theory before explaining the problems it faces. |
Conceptual interaction problem | Elisabeth's objection that a non-extended mind cannot causally interact with an extended body if causation requires contact between extended physical bodies. | Reconstruct and evaluate Elisabeth's objection. |
Extension | The characteristic Descartes attributes to physical bodies, which occupy the physical category contrasted with non-extended mind. | Explain why contact appears problematic for Cartesian mind-body interaction. |
Empirical interaction problem | The objection that non-physical mental causation conflicts with empirical evidence or scientific theory. | Explain the second specified issue for interactionist dualism. |
Conservation of energy | The physical principle identified by AQA as an example relevant to the empirical interaction problem. | Explain why non-physical causation may appear difficult to reconcile with physical science. |
Hints from the Examiner Reports 💡
No lesson-specific examiner guidance was identified in the provided reports.
Common Mistakes ⚠️
Mistake: Saying interactionist dualism allows causation in only one direction
Why this is incorrect:Interactionist dualism involves two-way causal interaction. Mental states can affect physical states, and physical states can affect mental states.
How to improve:Remember both directions:
mental → physical
physical → mental
Mistake: Saying Elisabeth simply argues that mind and body are different
Why this is incorrect:Descartes already accepts that they are different. Elisabeth's argument concerns the consequences of that difference for causal interaction.
How to improve:Explain the full reasoning: causation requires contact between extended bodies, but the mind is non-extended, so physical contact and therefore interaction appear impossible.
Mistake: Treating the conceptual and empirical interaction problems as identical
Why this is incorrect:The conceptual problem asks whether interaction between distinct substances makes coherent sense. The empirical problem asks whether such interaction is compatible with scientific evidence and physical theory.
How to improve:Use the contrast:
conceptual = can it make sense?
empirical = is it compatible with the physical evidence?
Mistake: Saying the empirical problem is simply that the mind cannot touch the body
Why this is incorrect:That is part of Elisabeth's conceptual interaction problem.
How to improve:For the empirical problem, discuss the apparent conflict between non-physical mental causation and scientific theory, including conservation of energy.
Mistake: Assuming that lack of a complete causal explanation automatically proves interaction impossible
Why this is incorrect:An explanatory gap and a logical contradiction are not automatically the same thing.
How to improve:Ask whether the objection establishes incoherence, or whether it shows that interactionist dualism still owes a satisfactory explanation.
Exam-Style Questions ✍️
Question 1
Define interactionist dualism.(3 marks)
Question 2
What is Elisabeth, Princess of Bohemia's conceptual interaction problem?(5 marks)
Question 3
A dualist claims:
"My desire to raise my arm causes my body to move."
Explain why Elisabeth's conceptual interaction problem challenges this claim.(5 marks)
Question 4
Explain the empirical interaction problem for interactionist dualism.(5 marks)
Question 5
Explain one important difference between the conceptual and empirical interaction problems.(5 marks)
Question 6
A philosopher argues:
"Elisabeth has not shown that all causation must involve physical contact, so her argument does not prove that mind-body interaction is impossible."
Explain and evaluate this response.(12 marks)
Question 7
Explain and compare the conceptual and empirical interaction problems for interactionist dualism.(12 marks)
Question 8
Can interactionist dualism give a coherent account of causal interaction between the mental and physical?(25 marks)
Indicative answers and marking guidance
Question 1
Interactionist dualism is a version of dualism according to which mental and physical states, substances or properties are ontologically distinct but causally interact in both directions.
Mental events can cause physical events, such as a desire causing bodily movement.
Physical events can cause mental events, such as bodily impact causing pain.
Question 2
Elisabeth's conceptual interaction problem challenges Cartesian interactionist dualism.
Descartes treats the body as extended physical substance and the mind as non-extended mental substance.
Elisabeth argues that causation is conceptually constituted by contact between extended physical bodies.
Because a non-extended mind cannot make physical contact with or stand in physical proximity to a body, she concludes that mind and body cannot causally interact in the way Cartesian dualism requires.
Question 3
The interactionist claims that a mental desire produces a physical bodily movement.
Elisabeth argues that causal interaction requires the sort of contact possible between extended physical bodies.
However, the Cartesian mind is non-extended.
It therefore cannot make physical contact with the body.
If Elisabeth's account of causation is correct, the mental desire cannot cause the bodily movement, so the example fails to establish coherent mind-body interaction.
Question 4
The empirical interaction problem claims that interactionist dualism conflicts with empirical evidence or scientific theory.
Interactionism claims that a non-physical mind or mental state can cause a change in the physical body.
However, physical changes are governed by physical laws.
AQA gives the Newtonian law concerning the conservation of energy as an example.
The interactionist must therefore explain how a non-physical cause can alter physical events without conflicting with the relevant physical account.
Question 5
The conceptual interaction problem concerns whether interaction between non-extended mind and extended body is coherent at all.
It is associated with Elisabeth and focuses on the idea that causation requires contact between extended physical bodies.
The empirical interaction problem instead concerns whether non-physical mental causation is compatible with empirical evidence and physical science, including conservation of energy.
The first therefore concerns conceptual coherence, while the second concerns empirical compatibility.
Question 6
The response attacks the first premise of Elisabeth's reasoning.
Her argument requires:
Causal interaction requires contact between extended physical bodies.
If this is false, then the fact that mind is non-extended does not by itself show that mind cannot cause physical effects.
The objection therefore prevents Elisabeth from moving automatically from "mind cannot make physical contact" to "mind cannot cause body".
However, this does not by itself establish interactionist dualism.
The dualist still needs to explain how a non-extended mind can exercise causal influence over an extended body.
The response may therefore show that Elisabeth has not demonstrated impossibility while leaving an important explanatory problem unresolved.
Question 7
A strong answer should distinguish and explain both specified problems.
The conceptual interaction problem, associated with Elisabeth, argues that causation is constituted by contact between extended physical bodies. Descartes' mind is non-extended, so it cannot make physical contact with the body. It therefore appears incapable of producing physical effects.
The empirical interaction problem starts instead from scientific evidence and theory. If a non-physical mental state produces a physical change, interactionist dualism must explain how this is compatible with physical principles governing the body, such as conservation of energy.
The objections are therefore related but distinct.
Elisabeth challenges whether the interaction is conceptually coherent.
The empirical problem challenges whether it is scientifically compatible with the physical world.
A successful defence of interactionist dualism would therefore need to address both problems rather than treating an answer to one as an answer to the other.
Question 8
A successful 25-mark response should explain interactionist dualism accurately and evaluate both specified problems.
Relevant material includes:
dualism as an ontological distinction between mental and physical
two-way causal interaction
mental events causing physical events
physical events causing mental events
the Cartesian distinction between non-extended mind and extended body
Elisabeth's conceptual interaction problem
the claim that causation requires contact between extended bodies
the conclusion that non-extended mind cannot causally interact with body
whether Elisabeth has established that all causation requires physical contact
the distinction between unexplained interaction and impossible interaction
the empirical interaction problem
the apparent conflict between non-physical mental causation and scientific theory
conservation of energy as the specified example
whether the empirical problem actually demonstrates that non-physical causation is impossible
the distinction between conceptual coherence and empirical compatibility
comparison with Problems for Epiphenomenalist Dualism [Problems for Epiphenomenalist Dualism]
a reasoned judgement about whether interactionist dualism provides an adequate account of mind-body causation
A strong evaluation will avoid treating the difficulty of explaining interaction as automatically equivalent to a proof of impossibility. However, interactionist dualism carries a substantial explanatory burden. It must show both how a non-extended mental reality can coherently cause physical change and how that causal influence can be compatible with the empirical principles governing physical events.
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