Ernst Cassirer's Determinism and Indeterminism in Modern Physics (DI; Cassirer, 1936/1956) constitutes a major but systematically overlooked transformation in the philosophy of quantum mechanics. Against interpretations that treat the text as a late application of his earlier structuralism, this article argues that quantum mechanics forces a fundamental reconstruction of causal order and scientific objectivity. Following the dissolution of Laplacean determinism, causality is no longer directed at ‘things’ in the world, but functions as a regulative demand that experience be rendered intelligible. Accordingly, causal order does not map to a pre-given reality but is progressively constituted from within experience through recursive processes of functional co-ordination (Zuordnung). This reconstruction culminates in a participatory account of objectivity organised through three mutually conditioning levels – measurements, laws, and principles. The upshot is that physical objects emerge as invariant nodes within relational structure; objects are fixed as objective relations. On this basis, the article shows that neither epistemic nor ontic structural realism adequately captures Cassirer's position and develops in response a provisional functional ontology in which a co-ordinating subject and an indeterminate relational domain jointly constitute the transcendental conditions of objectivity. The article concludes by situating DI within a broader participatory tradition in the foundations of physics, arguing that Cassirer's recursive and observer-dependent account of objectivity anticipates key developments in second-order cybernetics and participatory approaches to quantum mechanics.
Ernst Cassirer's Determinism and Indeterminism in Modern Physics (DI; Cassirer, 1936/1956) constitutes a major but systematically overlooked transformation in the philosophy of quantum mechanics. Against interpretations that treat the text as a late application of his earlier structuralism, this article argues that quantum mechanics forces a fundamental reconstruction of causal order and scientific objectivity. Following the dissolution of Laplacean determinism, causality is no longer directed at ‘things’ in the world, but functions as a regulative demand that experience be rendered intelligible. Accordingly, causal order does not map to a pre-given reality but is progressively constituted from within experience through recursive processes of functional co-ordination (Zuordnung). This reconstruction culminates in a participatory account of objectivity organised through three mutually conditioning levels – measurements, laws, and principles. The upshot is that physical objects emerge as invariant nodes within relational structure; objects are fixed as objective relations. On this basis, the article shows that neither epistemic nor ontic structural realism adequately captures Cassirer's position and develops in response a provisional functional ontology in which a co-ordinating subject and an indeterminate relational domain jointly constitute the transcendental conditions of objectivity. The article concludes by situating DI within a broader participatory tradition in the foundations of physics, arguing that Cassirer's recursive and observer-dependent account of objectivity anticipates key developments in second-order cybernetics and participatory approaches to quantum mechanics.
This article deals with the Copenhagen interpretation of quantum mechanics and its epistemological discussion by Ernst Cassirer and Richard Hönigswald. The starting point is Cassirer's treatise Determinism and Indeterminism in Modern Physics, published in Stockholm. Both philosophers and several physicists were involved in the subsequent exchange of letters. From a physical point of view, the Copenhagen interpretation was particularly criticised by v. Laue and Einstein. Both demanded a revision of the foundations of quantum mechanics or a critical examination of essential physical concepts. The epistemological implications of the Copenhagen interpretation were rejected, in particular that the interactions between observation, the observed and the observer in quantum physics experiments should lead to a renunciation of the concept of causality or an objectively unambiguous description of natural processes. Cassirer argues here that quantum mechanics fulfils the epistemological requirement of transforming ontological “concepts of things” into epistemological concepts of relations and is therefore compatible with the neo-critical approach he advocates. At the same time, Hönigswald was working on two major treatises on the structure of physics and the concept of causality. Here he undertakes an epistemological foundation of physics as a whole. A transcendental foundation of the concept of experience and its specifications in principles such as contemplation, observation or experiment appears to be called for. Hönigswald therefore essentially rejects the Copenhagen interpretation, as it draws epistemological consequences by physical means and thus inadmissibly reverses the transcendentally necessary relations of justification. These arguments are examined and could be used for a current discussion on the epistemological foundations of quantum mechanics and physics as a whole. A post-Neo-Kantian, transcendental philosophical foundation of scientific knowledge, especially of modern physics, seems possible and necessary.
This article revisits Ernst Cassirer’s philosophy of quantum physics as developed in his last epistemological work Determinismus und Indeterminismus in der modernen Physik (1936), in particular his main thesis which posits that causality can be maintained in quantum theory, provided its object is re-conceptualized. I study the ranking of the principle of causality in Cassirer’s hierarchy of physical knowledge, and show that its role is both constitutive and regulatory. This is linked to Cassirer’s rejection of the Kantian faculty of intuition. I review other characteristics of Cassirer’s conception of physical theory (in particular holism) and analyze in detail how Cassirer manages to shift from an observationalist interpretation of Heisenberg’s relations (negative, as a lack of information) to a constitutive interpretation (positive, as a new definition of the object) of these relations. I conclude by showing that Cassirer’s interpretation of quantum theory is more promising than Friedman’s Kant-inspired « relativized a priori » conception.
With the advent of quantum theory, the philosophical distinction between “what appears to be” and “what is reasoned to be” has once again, after several centuries of easy dismissal by classical mechanistic materialism, become an important feature of physics. In recent well-regarded interpretations of quantum physics, including those proposed by Robert Griffiths, Roland Omnès, and Nobel laureate Murray Gell-Mann, we have seen careful investigations into the physical (i.e., not “merely philosophical”) distinction between the order of contingent causal relation and the order of necessary logical implication. I argue that a careful philosophical exploration of the function of the logical order in modern interpretations of quantum physics compels the abandonment of derivative classical, dualistic understandings of “determinism versus indeterminism,” “logical necessity versus causal contingency,” “subject versus object,” “epistemic versus ontological,” among other fundamental dualisms. The incoherence underlying this classical understanding of these principle-pairs as mutually exclusive features of reality can be relieved if they are instead understood as mutually implicative features of fundamental units of relation or “quantum praxes.”
This chapter examines Cassirer's view on contemporary science. It revisits Cassirer's lesser-known work Determinism and Indeterminism in Modern Physics and argues that it harbors a significantly new stage of his philosophy of physical science. On the one hand, this work presents the quantum formalism as a limiting pole of the Bedeutungsfunktion, the highest mode of symbolic formation according to Cassirer’s “phenomenology of cognition.” Inspired by Paul Dirac, Cassirer understands quantum mechanics as a symbolic calculus for deriving probabilistic predictions of measurement outcomes without regard to underlying wave or particle “images” – or, as an exemplar of abstract symbolic thought. On the other hand, Cassirer recognizes the philosophical significance of the use of group theory in quantum mechanics as advancing a purely structural concept of object in physics. Hence, Ryckman reveals that Cassirer drew epistemological consequences from the symbolic character of contemporary physical theory that retain relevance for philosophy of science today.
Abstract Stöltzner coined the expression ‘Vienna indeterminism’ to describe a philosophical tradition centered on the Viennese physicist Exner, serving as the ‘historical link’ between Mach and Boltzmann, on the one hand, and von Mises and Frank, on the other. During the early 1930s debate on quantum mechanics, there was a ‘rapprochement’ between Vienna indeterminism and Schlick’s work on causality. However, it was Cassirer’s 1936 monograph Determinismus und Indeterminismus that showed a full ‘convergence’ with major tenets of Vienna indeterminism: the fundamentality of statistical laws, the frequency interpretation of probability, and the statistical interpretation of the uncertainty relations. Yet, Cassirer used these conceptual tools to pursue ‘in parallel’ different philosophical goals. While for the Viennese quantum mechanics represented a fatal blow to the already discredited notion of ‘causality,’ for Cassirer it challenged the classical notion of ‘substantiality,’ the ideas of ‘particles’ as individual substances endowed with properties. The paper concludes that this ‘parallel convergence’ is the most striking and overlooked aspect of Determinismus und Indeterminismus, serving as the keystone of its argumentative structure.
This paper argues that, where deterministic and indeterministic formulations agree on empirically corroborated structure while differing in their completion of structure that remains empirically underdetermined, features invariant across these formulations warrant ontological commitment, whereas any warrant attaching to features that vary across them is categorically more provisional. Because deterministic and indeterministic completions are always formally available, while additional grounds for preferring particular completions are contingent and defeasible, empirically corroborated structure alone cannot determine whether reality is fundamentally deterministic or indeterministic, or whether that very distinction belongs only to specific representations of it.
On this basis, I advance a model-invariance criterion according to which structural features are candidates for realist commitment insofar as they are empirically corroborated within a regime and preserved across the admissible formulations of that structure. I show how such invariant content can be characterised in mathematically intelligible ways, yielding a fallibilist form of structural realism grounded in model-invariance rather than in the specific form of any given mathematical representation. Features such as conservation relations, invariant measures, symmetries, and probability or correlation structures over observable histories may satisfy this criterion. By contrast, the localisation of modal selection---whether in fine-grained initial conditions, stochastic outcomes, or state-update and collapse mechanisms---may vary across empirically admissible formulations and therefore constitute a gauge-like representational freedom.
This framework offers a realist ontology for modern physics that combines empirical openness with resistance to metaphysical overreach.