alchemical worldview · participatory observation
Quantum mechanics enters the depth-psychology corpus primarily through two interlocking vectors: the technical epistemology of Wolfgang Pauli, who engages the theory on its own mathematical and philosophical terms, and the broader interpretive tradition—represented by McGilchrist, Thompson, and the Pauli–Jung dialogue—that appropriates quantum phenomena as a warrant for revisioning the observer–observed relationship. Pauli, writing both as physicist and as interlocutor of Jung, treats complementarity, the uncertainty principle, and the exclusion principle as genuine conceptual revolutions that transform the classical notion of causality into something closer to a network of 'connections' in nature—a move with explicit consequences for the psycho-physical problem. McGilchrist extends this argument by invoking quantum entanglement and wave-function collapse as evidence that consciousness is causally participant in the constitution of reality, not merely its passive recorder. Thompson introduces a philosophically more cautious note, questioning whether realist interpretations of quantum emergence are coherent at all. The alchemical-worldview and participatory-observation aliases signal the corpus's deepest ambition: to find in quantum indeterminacy a scientific echo of the alchemist's transformative participation in matter, and of Bohr's insistence that the observer cannot be cleanly severed from the observed. The term thus marks a contested frontier between physics, depth psychology, and ontology.
Quantum theory … involves, in an essential way, the causal participation of the minds of us observers, while classical mechanics strictly bans any such effect of mental realities on the world of matter.
McGilchrist, citing Stapp, argues that quantum theory's core departure from classical physics is its mandatory inclusion of the observer's mind as a causal factor in actualising physical reality.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021thesis
if we find that quantum mechanics is in operation cognitively, then it could be a necessary component of consciousness … it might underlie the collapse of the wave function … the outcome of the observer's brain and the observed system becoming entangled in consciousness.
McGilchrist presents quantum entanglement and wave-function collapse as possible mechanisms linking mind and matter, making quantum mechanics a necessary, not merely metaphorical, component of consciousness.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021thesis
quantum mechanics may be regarded as the rational generalisation of classical physics, and complementarity as the generalisation of causality in the narrower sense … quantum mechanics rests on the existence of a sharp cut between observer or instrument of observation on one hand and the system observed on the other.
Pauli identifies complementarity as quantum mechanics' replacement for classical causality, while noting that the observer–system boundary, though necessary, conceals unresolved fundamental problems.
, Writings on Physics and Philosophy, 1994thesis
the universal validity of the uncertainty relation is a necessary condition that quantum mechanics should be free from contradictions.
Pauli demonstrates that the uncertainty relation is not merely a practical limitation but the logical precondition for quantum mechanics' internal consistency.
, Writings on Physics and Philosophy, 1994thesis
the idea of causality, criticised earlier from the empirical standpoint by D. Hume, has undergone a further essential generalisation in quantum mechanics.
Pauli situates quantum mechanics within the historical critique of causality, arguing that it completes rather than merely revises the classical causal framework.
, Writings on Physics and Philosophy, 1994thesis
their tendency to extend the old narrower idea of 'causality (determinism) to a more general form of 'connections' in nature, a conclusion to which the psycho-physical problem also points.
Pauli explicitly links quantum mechanics' generalisation of causality to the psycho-physical problem, anticipating a unified framework that would encompass both physics and depth psychology.
, Writings on Physics and Philosophy, 1994thesis
we are dealing here with an invisible reality, in which features are becoming fundamental which are at least negligible and without practical importance for macroscopic objects … the point of view called 'complementarity', which was developed by Bohr and others for this purpose, though shared by the majority of physicists, did not remain without opposition.
Pauli frames quantum mechanics as a science of invisible, sub-macroscopic reality whose epistemological consequences—particularly complementarity—remain genuinely contested.
, Writings on Physics and Philosophy, 1994supporting
there can be an essential limitation to the simultaneous use of two or more classical concepts or visualisable images, on account of the finiteness of the quantum of action … This apparent dilemma between wave and particle concept … was repeated for matter.
Pauli explains how the wave–particle dilemma exemplifies the structural complementarity that quantum mechanics imposes on all classical conceptual pairs.
, Writings on Physics and Philosophy, 1994supporting
Heisenberg's matrix theory … the probability amplitudes of the virtual oscillators and the energy values of the stationary states were for the first time derived by means of a coherent mathematical formalism … many problems of physical interpretation had yet to be solved.
Pauli traces the historical consolidation of quantum mechanics through Heisenberg, Schrödinger, Born, and Dirac, emphasising that formal success preceded interpretive resolution.
, Writings on Physics and Philosophy, 1994supporting
Heisenberg, who recognised the calculus of matrix multiplication as the appropriate key to a quantitative translation of classical mechanics into a rational quantum mechanics — a translation which Bohr's correspondence principle had indeed aimed at but had not been able to carry through.
Pauli credits Heisenberg's matrix mechanics as the decisive formal step that transformed Bohr's heuristic correspondence principle into a rigorous quantum theory.
, Writings on Physics and Philosophy, 1994supporting
the first assumption is never realized in nature. Moreover, it is only the third assumption that is in accordance with … the exclusion principle and Quantum Mechanics.
Pauli argues that of the three logically possible symmetry classes for particle ensembles, only the antisymmetrical class—governed by the exclusion principle—is realised in nature.
, Writings on Physics and Philosophy, 1994supporting
a half-integer value of the spin quantum number is always connected with antisymmetrical states (exclusion principle), an integer spin with symmetrical states … it can certainly not be explained by non relativistic wave mechanics.
Pauli establishes the spin–statistics connection as a law requiring relativistic quantum mechanics for its explanation, underscoring the theory's depth beyond its non-relativistic formulation.
, Writings on Physics and Philosophy, 1994supporting
quantum field theory is the best description of physical reality we have … quantum theories penetrate into more profound strata of reality than all previous theories. The theory of relativity itself now appears to us as simply a macroscopic and statistical view of phenomena.
McGilchrist, drawing on de Broglie and Bergson, contends that quantum field theory supersedes both classical and relativistic physics by penetrating deeper strata of physical reality.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021supporting
it is necessary somewhere or other to include a rule for the attitude in practice of the human observer … which takes account of the subjective factor as well.
Pauli acknowledges that statistical interpretations of quantum phenomena cannot be rendered empirically operative without incorporating the subjective stance of the human observer.
, Writings on Physics and Philosophy, 1994supporting
I proposed instead of it the assumption of a new quantum-theoretic property of the electron, which I called a 'two-valuedness not describable classically'.
Pauli recounts his introduction of electron spin as a classically indescribable quantum property, marking the historical moment at which quantum mechanics definitively exceeded classical conceptual resources.
, Writings on Physics and Philosophy, 1994supporting
if quantum mechanics is supposed to be the best case of ontological emergence, then it would seem a realist interpretation of quantum mechanics is being assumed. Whether there is a coherent realist interpretation of quantum mechanics is an unresolved matter.
Thompson cautions that appeals to quantum mechanics as evidence for ontological emergence presuppose a realist interpretation whose coherence remains philosophically unresolved.
, Mind in Life: Biology, Phenomenology, and the Sciences of Mind, 2007supporting
An interference setup for a photon is accordingly a single whole; it cannot be decomposed into causal sequences which can be followed in space and time … Every attempt in this way to follow the photon in space and time would destroy the interference phenomenon.
Pauli illustrates the holistic, non-decomposable character of quantum measurement by showing that any spatiotemporal tracking of a photon through an interference apparatus necessarily destroys the phenomenon.
, Writings on Physics and Philosophy, 1994supporting
already in 1924, before the electron spin was discovered, I proposed to use the assumption of a nuclear spin to interpret the hyperfine-structure of spectral lines.
Pauli offers autobiographical testimony to his role in the historical development of quantum spin theory, contextualising the exclusion principle's origins.
, Writings on Physics and Philosophy, 1994aside
classical mechanics must already break down in the case of the helium spectrum … the usefulness of this theory even for small quantum numbers is restricted to very special systems.
Pauli documents the empirical failure of classical mechanics for multi-electron systems, establishing the historical necessity of quantum mechanics' conceptual break.
, Writings on Physics and Philosophy, 1994aside
Jung deepened his reflections … His study of alchemy brought him to an understanding of the unconscious as a process, and he began to clarify his view that the psyche can be transformed.
Papadopoulos situates Jung's alchemical studies as the bridge between psychological transformation and the participatory worldview that resonates with quantum mechanics' observer-dependence.
, The Handbook of Jungian Psychology: Theory, Practice and Applications, 2006aside