Objections to Interactionist Dualism

Interactionist dualism faces six major philosophical objections: the pairing problem, conservation laws, parsimony, the decoherence objection, the evolutionary argument, and Kim’s exclusion argument. This page treats each objection and the responses available to the interactionist—particularly within the quantum framework The Unfinishable Map adopts. The key finding: five objections have principled responses, and the sixth (evolution) actually supports interactionism against its main rival, epiphenomenalism.

The Pairing Problem

The Objection

Jaegwon Kim’s pairing problem (2005) asks: even granting that consciousness could causally affect physics, what pairs a particular mind with a particular body?

Two minds M1 and M2 interact with two bodies B1 and B2. Both intend to raise their hand. M1’s intention causes B1’s hand to rise; M2’s causes B2’s. But in virtue of what is M1 paired with B1 rather than B2? For physical causation, spatial relations provide the answer. If minds are non-spatial, no spatial relation can ground the pairing.

The Spatial Location Response

Many contemporary dualists (Hasker, Zimmerman) accept that minds are spatially located—in the brain region where they causally interact. This dissolves the pairing problem while maintaining ontological distinctness. Kim objects that two indiscernible souls might occupy the same region, but interactionists can hold that souls are individuated by their causal histories—ongoing interaction with a particular body creates individuation.

The Haecceities Response

Bailey, Rasmussen, and Van Horn (2011) argue there is “no pairing problem.” If haecceities (primitive “thisness”) exist, they can ground the pairing without spatial location. If haecceities don’t exist, the pairing problem generalizes to all causation—what pairs any cause with any effect? The dualist faces no special difficulty.

The Quantum Fit

The Map’s Minimal Quantum Interaction framework provides a natural answer. If consciousness interfaces with the brain at quantum indeterminacies in specific neural structures, consciousness is located where those structures are. Interface locality reinforces this: the quantum Zeno mechanism requires observer-system coupling that exists only within one’s neural substrate. The pairing is built into the mechanism.

Conservation Laws

The Objection

Since Leibniz, critics argue that mind-body interaction violates conservation of energy and momentum. If mind causally affects body, energy must enter the physical system from outside. Papineau (2001) develops this into an argument for causal closure; Carroll (2016) demands to know what particles a soul is made of.

For comprehensive treatment, see conservation-laws-and-mental-causation. The key responses:

Response 1: Conservation Is Local and Conditional

Pitts and Cucu demonstrate that conservation laws are local and conditional. Noether’s theorem shows conservation arises from symmetries: when time-translation symmetry holds, energy is conserved. If an external influence breaks the symmetry, conservation fails at that location. As they argue: expecting conservation in the brain simply assumes the falsehood of dualism—the objection begs the question.

Response 2: Selection Not Injection

The Map’s primary response: at quantum indeterminacies, consciousness selects among possible outcomes without injecting energy. All outcomes are already present in the wavefunction with their associated energies. Physics determines that one will become actual, with probabilities for each, but doesn’t determine which. Consciousness selects without energy injection—conservation equations are satisfied for every possible outcome.

Quantum entanglement provides precedent: Bell’s theorem shows correlations between distant particles that cannot be explained by local energy transfer. If physics permits such connections without energy exchange, conceptual space exists for mind-matter interaction without energy injection.

Parsimony

The Objection

Physicalism is simpler than dualism, therefore preferable by Occam’s Razor: fewer ontological commitments, all else being equal.

Response 1: All Else Isn’t Equal

Parsimony applies only when theories have equal explanatory power. The hard problem shows that physical descriptions don’t entail phenomenal experience. The explanatory-gap has resisted closure despite decades of effort. A simpler theory that doesn’t explain the data isn’t preferable.

Response 2: Type vs. Token Parsimony

Dualism adds one ontological type (mind), not millions of tokens. Physics posits multiple fundamental types—fermions, bosons, four forces—without parsimony complaint. Why should consciousness be different?

Response 3: Consciousness as Datum

If consciousness is real and irreducible, ignoring it isn’t parsimony—it’s ignoring evidence. Physical theories are inferred from observations, which are conscious experiences. Eliminating consciousness to achieve parsimony eliminates the foundation to simplify the building.

Response 4: Occam’s Razor Has Limits

The Map’s fifth tenet. Parsimony is a methodological heuristic, not a metaphysical truth. It has repeatedly pointed away from truth: atomic theory posited invisible entities when continuous matter seemed simpler; quantum mechanics replaced deterministic simplicity with superposition. The apparent simplicity of physicalism may reflect ignorance rather than reality.

The Decoherence Objection

The Objection

The decoherence objection targets quantum-based interactionism specifically. Warm biological systems destroy quantum coherence almost instantly: molecular systems at body temperature decohere in femtoseconds (10⁻¹⁵ seconds), while neural processes operate on milliseconds (10⁻³ seconds)—a gap of twelve orders of magnitude. Tegmark (2000) calculated that quantum coherence in brain microtubules would decay in about 10⁻¹³ seconds.

Response 1: Quantum Biology Evidence

Recent experiments complicate the “warm means no quantum” picture. Quantum coherence in photosynthetic light-harvesting complexes persists far longer than Tegmark-style calculations predicted. Kalra et al. (2025) found microtubule-stabilizing drugs delay anesthesia onset in mice, suggesting microtubule dynamics matter for consciousness. Kerskens and Pérez (2022-2023) detected possible entanglement signatures in human brain MRI correlating with working memory. These don’t prove quantum consciousness but demonstrate that quantum effects in biological systems are more robust than assumed.

Response 2: The Measurement Question

Critically, decoherence does not solve the measurement problem. Decoherence explains why interference effects wash out, but not why we see definite outcomes. After decoherence, quantum mechanics still describes the total system as a vast entangled superposition. If definite outcomes require something beyond decoherence, the question of what selects outcomes remains open. The Map’s No Many Worlds tenet holds that genuine selection occurs. Whatever does the selecting might be consciousness.

Response 3: Non-Computational Selection

Even if decoherence eliminates quantum computing in the brain, it may not eliminate quantum selection. Consciousness might select among classical-looking outcomes that decoherence produces—a weaker claim than Orch OR, but still providing room for mental causation where physics leaves outcomes undetermined.

The Evolutionary Argument

The Objection

Often presented as objecting to dualism, this argument actually targets epiphenomenalism and supports interactionism. Pleasures correlate with survival-beneficial stimuli; pains with harmful stimuli. Natural selection can only favor traits with causal effects on behavior. Therefore, consciousness has causal effects (contra epiphenomenalism), and interactionism (or physicalism) is true.

Why This Supports Interactionism

Interactionism holds that consciousness causes physical effects—exactly what the evolutionary argument requires. The argument targets only views that deny mental causation (epiphenomenalism, parallelism). The Map can use this offensively: if consciousness causes nothing, evolution can’t explain the precise tracking of phenomenal states with fitness-relevant behaviors.

The Epiphenomenalist Response

Epiphenomenalists respond that consciousness might be a “spandrel”—a by-product of selected neural processes. But this explains why consciousness exists, not why the pain/pleasure correlations are so precise. A causally inert by-product might exist without being finely tuned. The precision of valence-fitness correlation suggests causal involvement.

The Exclusion Argument

The Objection

Kim’s exclusion argument: mental properties supervene on physical properties. If physical property P is sufficient for effect E, mental property M seems causally redundant—P “screens off” M. Therefore, M either is identical to P (reductionism) or causes nothing (epiphenomenalism).

The Drainage Problem

Kim calls this “causal drainage”—efficacy drains to fundamental physics. But this threatens all higher-level causation: does temperature cause anything, or just molecular motion? The generalization either undermines all special sciences or suggests the exclusion reasoning is flawed.

Response 1: Interventionism

James Woodward’s interventionist theory defines causes as factors whose manipulation changes effects. Intervening on mental states (through reasoning, therapy, meditation) produces different physical outcomes, establishing mental causation via counterfactuals.

Response 2: Levels and Proportionality

Yablo argues mental properties may be more proportional causes. “Being in pain” may be the right level for explaining avoidance behavior; neural details may be over-specific. One cause under two descriptions, not two competing causes.

Response 3: Quantum Insufficiency

The Map’s primary response: at quantum indeterminacies, P is not sufficient for E—physics determines probabilities but not outcomes. Where physics is genuinely incomplete, mental properties fill the gap without exclusion. There is no sufficient physical cause to do the excluding.

Response 4: Delegatory Preemption

Delegatory dualism (Saad, 2025) offers a response independent of quantum mechanics. When a physical brain state’s default causal profile matches an experience’s causal profile, the experience preempts the physical state’s causal role through causal-delegation. Only one cause operates—the experience does the causal work while the physical state is sidelined. Saad also distinguishes observational closure from universal closure: mental causation need not violate what physics experiments detect.

Connection to the Luck Objection

The exclusion argument parallels the luck objection to libertarian free will. The Map’s response: consciousness selects among undetermined possibilities—neither redundant nor arbitrary. The quantum Zeno mechanism and delegatory preemption both model how selection operates without overdetermination or randomness.

What Would Challenge This View?

Interactionism would face serious difficulty if: (1) all neural activity could be predicted from prior physical states with no residual indeterminacy; (2) the Many-Worlds interpretation were empirically confirmed; (3) mental causation required energy injection and systematic conservation violations were observed in neural systems; or (4) experiments demonstrated that no quantum effects survive in neural tissue.

These are empirical and interpretive questions, not settled by philosophical argument alone.

Summary

Relation to the Map’s Perspective

The objections to interactionism motivate rather than undermine the Map’s framework.

The Minimal Quantum Interaction tenet directly addresses the conservation and exclusion objections: consciousness acts where physics is incomplete, selecting among equi-energetic possibilities. No energy injection, no competition with sufficient physical causes.

The Occam’s Razor Has Limits tenet addresses parsimony: simplicity is unreliable when knowledge is incomplete.

The Bidirectional Interaction tenet affirms what the evolutionary argument requires: consciousness causes physical effects. The precision of valence-fitness correlation is explicable because phenomenal states genuinely influence behavior.

The pairing problem is addressed by interface locality: consciousness is located where its quantum interface is. Spatial location is compatible with metaphysical distinctiveness.

The exclusion argument receives two complementary responses: quantum insufficiency (physics leaves outcomes undetermined) and delegatory preemption (consciousness takes over causal work). Together, these show mental causation need not compete with or overdetermine physical causation.

Further Reading

• conservation-laws-and-mental-causation — Comprehensive response to the conservation objection
• delegatory-dualism — Saad’s solution to exclusion via preemption
• interactionist-dualism — The position these objections target
• pairing-problem — Detailed treatment of Kim’s pairing challenge
• causal-closure — The closure principle underlying the exclusion argument
• the-case-for-dualism — Positive arguments for the Map’s position
• quantum-consciousness — The mechanism for mind-matter interface
• decoherence — The quantum biology challenge and evidence
• interface-locality — Why consciousness can only select within its own brain
• objections-to-interactionist-dualism-2026-01-15 — Research notes for this article

References

1. Bailey, A., Rasmussen, J., & Van Horn, L. (2011). “No Pairing Problem.” Philosophical Studies, 154: 349-360.
2. Carroll, S. (2016). The Big Picture: On the Origins of Life, Meaning, and the Universe Itself. Dutton.
3. Collins, R. (2011). “The Energy of the Soul.” In M. Baker & S. Goetz (eds.), The Soul Hypothesis.
4. Cucu, A. C., & Pitts, J. B. (2019). “How Dualists Should (Not) Respond to the Objection from Energy Conservation.” arXiv:1909.13643.
5. Hagan, S., Hameroff, S. R., & Tuszyński, J. A. (2002). “Quantum computation in brain microtubules: Decoherence and biological feasibility.” Physical Review E, 65: 061901.
6. Jackson, F. (1982). “Epiphenomenal Qualia.” Philosophical Quarterly, 32: 127-136.
7. James, W. (1890). The Principles of Psychology.
8. Kalra, A. P., et al. (2025). “Microtubule-stabilizing drugs delay anesthetic-induced unconsciousness in mice.” Proceedings of the National Academy of Sciences, 122(3).
9. Kerskens, C. M., & Pérez, D. L. (2022-2023). “Experimental indications of non-classical brain functions.” Journal of Physics Communications.
10. Kim, J. (1998). Mind in a Physical World. MIT Press.
11. Kim, J. (2005). Physicalism, or Something Near Enough. Princeton University Press.
12. Papineau, D. (2001). “The Rise of Physicalism.” In C. Gillett & B. Loewer (eds.), Physicalism and Its Discontents. Cambridge University Press.
13. Pitts, J. B. (2022). “Conservation Laws and the Philosophy of Mind: Opening the Black Box, Finding a Mirror.” Philosophia, 50, 1065-1083.
14. Tegmark, M. (2000). “The importance of quantum decoherence in brain processes.” Physical Review E, 61: 4194-4206.
15. Woodward, J. (2003). Making Things Happen: A Theory of Causal Explanation. Oxford University Press.
16. Yablo, S. (1992). “Mental Causation.” Philosophical Review, 101: 245-280.