Abstract Heisenberg was a very dedicated Kantian, and viewed the discoveries of early twentieth century physics as disqualifying of the Kantian metaphysical worldview. He made an effort – not an especially successful one – to reconfigure the Kantian critique by replacing noumena with the quantum-level reality, and proposed a new entity as mediative between the quantum realm and the subject. The new entity, potentia (borrowed from Aristotle, and altered to serve Heisenberg’s purpose) fulfills that role by means of its hybrid nature: it’s partly mental, partly a reification of probabilities. This dual nature allows epistemic access to the probabilistic nature of quantum-level interactions, out of which our phenomenal world is realized when a measurement is made. How well this notion serves the purpose of rehabilitating the Kantian critique is questionable, as Heisenberg’s conception is problematic and, perhaps, internally inconsistent. My dissertation follows Heisenberg’s development of potentia, examines how well it addresses the failure of the Kantian problem, and asks whether his proposal is an obscurum per obscurius. Thereafter I introduce a number of other, similar proposals to potentia, consider them on their own merits, compare them to Heisenberg’s conception, and use this conjunction of potentia proposals to made a judgment regarding whether the use of potentia is a philosophically defensible way of addressing the recondite problems of quantum mechanics.
Abstract Heisenberg was a very dedicated Kantian, and viewed the discoveries of early twentieth century physics as disqualifying of the Kantian metaphysical worldview. He made an effort – not an especially successful one – to reconfigure the Kantian critique by replacing noumena with the quantum-level reality, and proposed a new entity as mediative between the quantum realm and the subject. The new entity, potentia (borrowed from Aristotle, and altered to serve Heisenberg’s purpose) fulfills that role by means of its hybrid nature: it’s partly mental, partly a reification of probabilities. This dual nature allows epistemic access to the probabilistic nature of quantum-level interactions, out of which our phenomenal world is realized when a measurement is made. How well this notion serves the purpose of rehabilitating the Kantian critique is questionable, as Heisenberg’s conception is problematic and, perhaps, internally inconsistent. My dissertation follows Heisenberg’s development of potentia, examines how well it addresses the failure of the Kantian problem, and asks whether his proposal is an obscurum per obscurius. Thereafter I introduce a number of other, similar proposals to potentia, consider them on their own merits, compare them to Heisenberg’s conception, and use this conjunction of potentia proposals to made a judgment regarding whether the use of potentia is a philosophically defensible way of addressing the recondite problems of quantum mechanics.
Heisenberg offered an interpretation of the quantum state which made use of a quantitative version of an earlier notion, , of Aristotle by both referring to it using its Latin name,potentia, and identifying its qualitative aspect with . The relationship between this use and Aristotle's notion was not made by Heisenberg in full detail, beyond noting their common character: that of signifying the system's objective capacity to be found later to possess a property in actuality. For such actualization, Heisenberg requiredmeasurementto have taken place, an interaction with external systems that disrupts the otherwise independent, natural evolution of the quantum system. The notion of state actualization was later taken up by others, including Shimony, in the search for a law-like measurement process. Yet, the relation of quantum potentiality to Aristotle's original notion has been viewed as mainly terminological, even by those who used it thus. Here, I reconsider the relation of Heisenberg's notion to Aristotle's and show that it can be explicated in greater specificity than Heisenberg did. This is accomplished through the careful consideration of the role of potentia in physical causation and explanation, and done in order to provide a fuller understanding of this aspect of Heisenberg's approach to quantum mechanics. Most importantly, it is pointed out that Heisenberg's requirement of an external intervention during measurement that disrupts the otherwise independent, natural evolution of the quantum system is in accord with Aristotle's characterization of spontaneous causation. Thus, the need for a teleological understanding of the actualization of potentia, an often assumed requirement that has left this fundamental notion neglected, is seen to be spurious. This article is part of the themed issue ‘Second quantum revolution: foundational questions’.
I build upon Heisenberg’s proposal in 1958 that quantum states are ontologically real “potentia.” On this view reality consists in ontologically real Possibles and ontologically real Actuals. Then measurement converts Possibles to Actuals. This ontological hypothesis, explicit in Heisenberg’s proposal, suggests a natural place for “mind.” Mind converts Possibles to Actuals. This role for mind is a scientific hypothesis open to test. Modest evidence now supports the hypothesis. If very well confirmed, such results alter the foundations of quantum mechanics and afford a role of mind in the becoming of the universe. More, the ontological proposal is not a substance dualism, for potentia are not substances. Thus, this proposal for the role of mind does not seem to inherit many of the problems raised in a substance dualism such as Descartes’ Res cogitans and Res extensa, (Descartes), or in a substance neutral monism such as Russell, (Russell). The proposal is radical. Far more evidence is needed.
This chapter tries to pinpoint the epistemological information that a scientist (or an epistemologist) anxious to keep away from "metaphysical" commitments of any sort may nevertheless derive from quantum physics. But, valuable as it is (mainly as a guide for discriminating the genuinely scientific questions from those of a more "mixed" sort) this standpoint is not to be raised to the status of a universal way of thinking that would be the only admissible one. Within the veiled reality conception Einstemian separability, applies to empirical, not to independent, reality; which means that special relativity theory does not concern independent reality. In his mature years Heisenberg developed a conception of the world in which quite a central role is played by the notion of potentia. He associated wave functions to potentia. In a sense, Heisenberg's approach is ontological, but his ontology is of a subtle kind, for along with actuality it leaves room for potentialities.
In PHYSICS AND PHILOSOPHY: The Revolution Modern Science, (1) Werner Heisenberg aims, in not too technical language, to clarify change concept of reality manifesting itself quantum theory. He means to contribute to an articulation of the (not only epistemology) that underlies quantum theory's modified logical patterns. (2) To highly unusual degree, Heisenberg is gripped by sense of responsibility of modern quantum physicist to convey, language immediately intelligible to thinking public, his most serious and far-reaching reflections on metaphysical implications of his scientific work. One may go so far as to say that there is substantial evidence, partly within Physics and Philosophy, that Heisenberg regards such reflections and their public communication as his most important task. Heisenberg is especially apt for this intensely self-conscious contribution to humanity's historical-cultural development because his stature as principal originating architect of quantum at its most fundamental level is complemented by his deployment of an unusually broad and deep erudition and lifelong preoccupation with philosophic and artistic ontology from Anaximander through Kant and Goethe to Heidegger. No thinker has yet appeared who possesses such an authoritative combination of decisively necessary learning quantum physics and historical development of philosophic ontology. Despite flurry of renewed scholarly interest development of Heisenberg's scientific work, (3) and his complex relation to dramatic unfolding of German cultural his time, (4) there has yet to be executed sustained and philosophically critical interpretative commentary on this book that is his crucial philosophical-ontological legacy. Given profound ontological puzzles that continue to attend quantum physics and its implications for humanity's past as well as present and future conception of reality, such critical exegesis of this text is overdue. In what follows I try to extricate central nerve of Heisenberg's sinuously unfolding, dialectical exposition, and process to elucidate its strengths but also its deep ambiguities and perplexities--which express, I believe, fundamental dilemmas that pervade contemporary ontology. I Heisenberg makes inviolability of principle of noncontradiction cornerstone of his discussion. Unlike Aristotle (5) Heisenberg does not wrestle with challenge posed by possible denial of principle. He understands nonmathematical articulation of quantum to escape what would otherwise be devastating contradictions--most obviously contradiction wave/particle character of basic entities described by theory--through Bohr's famous principle of complementarity (which Heisenberg closely associates with von Weizsacker's notion of coexistent states), combined with Heisenberg's own principle of potentia, potentiality, potentialities. (6) II After brief introduction, Heisenberg his second chapter sketches history of quantum theory and process begins to explain what he means by potentia. In 1924 Bohr and his colleagues tried to solve apparent contradiction between picture and particle picture by concept of wave. The electromagnetic were treated not as 'real' waves but as mathematical descriptions of probabilities, every point relevant space, for the absorption (or induced emission) of light quantum by an atom at this point. Later this idea of was applied more effectively to much more abstract mathematical in many-dimensional configuration space that was discovered through researches of Schrodinger. Heisenberg reinterprets this mathematical probability wave ontological tenus, as signaling tendency [Tendenz] for a definite happening [einem bestimmten Geschehen], thus introducing remarkable kind of physical reality, standing middle between possibility and actuality: a quantitative version of old concept of 'dunamis' or 'potentia' philosophy of Aristotle. …
For Bohr quantum mechanics is complete. It expresses all that can be said about the atomic world, which he regards as a newly discovered and separate ontological component of reality, operating at the Planck scale, and describable only with a separate physics, namely, quantum mechanics. The classical world, in contrast, represents its binary and symbiotic counterpart, which is also ontologically substantive, but operates according to 'classical concepts'. The different physics of each component indicates a different ontology, the classical one is accessible to us, as we are classical objects, where the Planck scale does not apply, while the other is not. The measurement problem cannot therefore be solved through the discovery of hidden variables as these are classical in nature and therefore ineffective in explaining the quantum world. The measurement problem is therefore not due to epistemological limitations but emerges directly from a 'two worlds' dualism. Bohr's Copenhagen interpretation has therefore been erroneously misunderstood as a positivist retreat rather than as a view of reality proposing an ontological structure which is dualistic. l then propose similarities between Bohr and a ‘two worlds’ view of Kant, where noumena is an ontology which is inherently unknowable as it is devoid of a priori agents, much as the quantum world is unknowable as it is devoid of Bohr's classical concepts. However, just as classical concepts in Bohr are crucial in constituting classical reality, a priori intuitions and concepts in Kant are crucial in constituting phenomena, which are real ontological objects and not just appearances. The noumenal and quantum realms are therefore both substantive, but impossible to investigate. The phenomenal and classical worlds are also substantive. They are where objects and therefore meaning condenses. They are therefore open to our investigations.
The innovations to physics introduced by Werner Heisenberg and Niels Bohr via quantum mechanics presented them with epistemological and metaphysical challenges with which they were perpetually engaged. Among Heisenberg’s innovations are the complex-valued quantum state-transition probability amplitudes, and among Bohr’s the non- trivial role of the measuring environment in the procurement of data. In his article, Arkady Plotnitsky examines the responses of these two natural philosophers to these challenges through the lens of Pythagoreanism in terms of the rational and the irrational. He argues that Bohr’s philosophical stance is of the Reality-without-Realism sort in that Bohr holds quantum reality to be unrepresentable, and that Heisenberg’s is of the Pythagorean-realist sort in that Heisenberg comes to hold reality to be representable, but only by mathematics. Here, I argue that Heisenberg’s later representation of reality can be characterized as neo- Aristotelian because, among other relevant things, he intentionally develops quantum potentiality, which is essential to his late interpretation of the quantum formalism, as a quantification of Aristotle’s potentia.