In the philosophy of mind, double-aspect theory is the view that the mental and the physical are two aspects of, or perspectives on, the same substance. It is also called dual-aspect monism, not to be confused with mind–body dualism. The theory's relationship to neutral monism is ill-defined, but one proffered distinction says that whereas neutral monism allows the context of a given group of neutral elements to determine whether the group is mental, physical, both, or neither, double-aspect theory requires the mental and the physical to be inseparable and mutually irreducible (though distinct).
According to Harald Atmanspacher, "dual-aspect approaches consider the mental and physical domains of reality as aspects, or manifestations, of an underlying undivided reality in which the mental and the physical do not exist as separate domains. In such a framework, the distinction between mind and matter results from an epistemic split that separates the aspects of the underlying reality. Consequently, the status of the psychophysically neutral domain is considered as ontic relative to the mind–matter distinction."
Possible double-aspect theorists include:
- Baruch Spinoza, who believed that Nature or God (Deus sive Natura) had two aspects, Extension and Mind.
- Arthur Schopenhauer, who considered the fundamental aspects of reality to be Will and Representation.
- David Bohm, who used implicate and explicate order as a means of displaying dual-aspects.
- Gustav Fechner
- Mark Solms, neuropsychoanalist, for whom dual-aspect monism represents a matrix of ontological juxtaposition of psychoanalytical and neuroscientific knowledge from two distinct perspectives: looking from the inside and looking from the outside.
- George Henry Lewes
- John Polkinghorne
- Brian O'Shaughnessy on the dual aspect theory of the Will
- Thomas Nagel.
- David Chalmers, who explores a double-aspect view of information, with similarities to Kenneth Sayre's information-based neutral monism
Pauli and Jung's approach to dual-aspect monism has a very specific further feature, namely that different aspects may show a complementarity in a quantum physical sense. That is, the Pauli-Jung conjecture implies that with regard to mental and physical states there may be incompatible descriptions of different parts that emerge from the whole. This stands in close analogy to quantum physics, where complementary properties cannot be determined jointly with accuracy.
Atmanspacher further refers to Paul Bernays' views on complementarity in physics and in philosophy when he states that "Two descriptions are complementary if they mutually exclude each other, yet are both necessary to describe a situation exhaustively."
- Harald Atmanspacher; Christopher A. Fuchs (23 June 2014). The Pauli-Jung Conjecture and Its Impact Today. Andrews UK Limited. p. 182. ISBN 978-1-84540-759-9.
- Leopold Stubenberg. "Neutral Monism and the Dual Aspect Theory". Stanford Encyclopedia of Philosophy.
- Atmanspacher, Harald. The Pauli–Jung Conjecture and Its Relatives: A Formally Augmented Outline. Open Philosophy, Volume 3 Issue 1. De Gruyter | Published online: September 11, 2020. https://doi.org/10.1515/opphil-2020-0138.
- Stanford Encyclopedia of Philosophy: Schopenhauer
- Nagel, T. The View from Nowhere, Chapter III p28
- Atmanspacher, Harald; Fuchs, Christopher A. (2014). "Introduction". In Atmanspacher, Harald; Fuchs, Christopher A. (eds.). The Pauli–Jung Conjecture and Its Impact Today (2017 ed.). Imprint Academic. pp. 1–6. ISBN 978-18454-07599.
- Atmanspacher, Harald (2012). "Dual-aspect monism à la Pauli and Jung". Journal of Consciousness Studies. 19 (9): 96–120.
- Filk, Thomas (2014). "Quantum Entanglement, Hidden Variables, and Acausal Correlations". In Atmanspacher, Harald; Fuchs, Christopher A. (eds.). The Pauli–Jung Conjecture and Its Impact Today (2017 ed.). Imprint Academic. pp. 109–123. ISBN 978-18454-07599.
- Cambray, Joe (2014). "The Influence of German Romantic Science on Jung and Pauli". In Atmanspacher, Harald; Fuchs, Christopher A. (eds.). The Pauli–Jung Conjecture and Its Impact Today (2017 ed.). Imprint Academic. pp. 37–56. ISBN 978-18454-07599.
- Quote: "In the Pauli-Jung Conjecture these manifest aspects can even be incompatible or complementary, a feature that is not part of any other dual-aspect approach today. The possibility of incompatible descriptions of parts emerging from wholes clearly drives from Pauli's knowledge of this key concept of quantum theory, and it suggests that structural elements of quantum theory may elucidate our understanding of the psychophysical problem." Cited from: Harald Atmanspacher; Christopher A. Fuchs (23 June 2014). The Pauli-Jung Conjecture and Its Impact Today. Andrews UK Limited. pp. 1 ff. ISBN 978-1-84540-759-9.
- Harald Atmanspacher (2012). "Dual-Aspect Monism à la Pauli and Jung". Journal of Consciousness Studies. 19 (9–10): 96–120(25)..