Nobel Prize winner Werner Heisenberg's classic account explains the central ideas of the quantum revolution, and his celebrated Uncertainty Principle. Heisenberg reveals how words and concepts familiar in daily life can lose their meaning in the world of relativity and quantum physics. This in turn has profound philosophical implications for the nature of reality.
Nobel Prize winner Werner Heisenberg's classic account explains the central ideas of the quantum revolution, and his celebrated Uncertainty Principle. Heisenberg reveals how words and concepts familiar in daily life can lose their meaning in the world of relativity and quantum physics. This in turn has profound philosophical implications for the nature of reality.
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. …
I do not recall having met an educated person who claims to know less about contemporary physics than I do. Nevertheless, it has been my contention that as physicians living in the early part of the second half of the twentieth century we have very strong obligations to understand as much as we can of the world we live in. Perhaps if this could be done on a large scale events might be bent somewhat to wise purposes rather than just letting them happen. The introduction of the uncertainty principle, for which Heisenberg received the Nobel Prize, may be of some comfort in its oversimplified form as applied to research in biology. As I understand it, his essential belief is that by the very act of measuring a variable factor is introduced which disqualifies the evidence by virtue of altering the thing measured. Certainly, in clinical investigation and in biology
COGNITIVE ASPECTS OF THE HEISENBERG PRINCIPLE I T HE Heisenberg uncertainty principle, like its rival theory of relativity/ has been one of the truly crucial phases in the physics of our day~ It did not, like the discovery of a new element or the Maxwell equations, simply indent the story of classical physics for a new paragraph. It was not only a new chapter but a new book. Detected, in the words of Heisenberg himself, when physics became self-critical, the principle is a statement of what is observable-like its contemporary, the theory of relativity. It was anew advance in method, so revolutionary indeed that physics has virtually lost meaning as content and become synonymous , as logical empiricism amply indicates, with mere rules of procedure. That science is developing into a system of logic, combining the Cartesian stress on clearness with the Kantian regulative idea, actually confirms a contention of traditional philosophy. It reveals that once we deny the colors and sounds, the life, lights, and purpose in our universe-as pure scientific method actually does-we are fated to deny much more than quality. Quality is in the order of form, substance, and being. The moment quality is banished from the real world, by the same 1 That all is not as peaceful and unified in physics as the layman sometimes believes can be seen in the deep cleavage between quantum and relativity mechanics. For the first, the exact specification of space (position) and time (velocity, momentum) has no meaning, while in relativity theory such exact description is the only meaning that can be had. Despite the efforts 'of leading physicists, including Dirac, to unite the two theories, the contradiction is so profound that one of these systems must eventually be abandoned or, more probably, both of them will be superseded. The recent work .of Schroedinger and apparently also of Einstei~ himself are directed to extend the general theory of relativity, making the current theory a special case just as Newtonian physics is a special case of present relativity mechanics. 474 COGNITIVE ASPECTS OF THE HEISENBERG PRINCIPLE 475 decree being itself-because it is an immediate, non-inertial (formal) thing like quality-is driven into its only possible exile, nothingness. It is not surprising then that, after modern physics· has finished its task, the universe should not only be emptied of its lights, its fragrance, its sweetness, and its music but should also be without being and without existence. The uncertainty principle has been much debated in modern thought. Its impact has brought a sad end to the pride of 19th century science since it prevents a complete knowledge of anything at all by shading into the darkness at least one of the two major factors that specify it. Shortly after the principle was born it was hailed by various authors as a proof of free will, of the possibility of religion, and of non-mechanistic concepts in biology. In a more consistent and challenging sense, it has often been taken to refute what the physicist calls causality and what the philosopher calls the order of nature. The fact of the matter is that if the senses alone supply knowledge, truly only one thing at a time can be apprehended. If Hume was right in philosophy, so is Heisenberg. But when sensism yields to an intellectual insight into reality, it is easy to refute the scientist's claim to dethrone the doctrine of nature's order which he could never detect, even in classical physics, by pointerreadings .2 But whatever the fate of the Heisenberg principle in cosmology , it has had a most fruitful career in the field of physics. To Heisenberg himself, the principle was a point of departure for an original development of quantum mechanics based on the " uncertainty " of position and momentum,.: 3 If, for example, measurements are made, under a microscope, of the position of an electron, the photon (light-particle), which impinges on the eye and thus conveys the required knowledge to the physicist, has had to collide with the electron, thus imparting an impact known as the Compton recoil. When • For ·a discussion of the order of nature, cf. J. Marling: The...
In 1926 Werner Heisenberg’s Uncertainty Principle set the field of quantum mechanics on a trajectory riddled with indeterminacy, a trajectory which stood in stark contrast with the classical Newtonian world causality and origin. In doing so, Heisenberg effectively created a new standard by which physicists conducted their science, broadened the scope of that science, and altered the very worldview of those physicists. Such paradigmatic upheaval fits the philosophical model of scientific progress posited by Thomas Kuhn. However, in the ever-changing and still-evolving world of quantum mechanics, Heisenberg’s revolutionary work uniquely strays from Kuhn’s model in its further implications.
For over nine decades, quantum mechanics has profoundly shaped our understanding of nature, offering explanations for the stability of atoms, the formation of mole cules, the properties of materials, and phenomena such as light or radioactivity. It is essential to modern technologies—from microchips to lasers—and underpins the physics of elementary particles. Yet, despite its successes, it remains a deeply mysterious theory, confronting a central enigma: why does the quantum world behave so differently from everyday reality? Elements such as superposition and quantum entanglement—which allow particles to exist simultaneously in multiple states or remain interconnected regardless of distance—contradict classical world intuitions. This gap between microscopic and macroscopic behavior has given rise to what is known as the “measurement problem,” raising fundamental questions about the nature of reality. Diverging interpretations have led to two major schools of thought: anti-realism, promoted by Niels Bohr, which holds that reality depends on the observer and their interaction with measurement instruments; and realism, supported by Albert Einstein, which argues that quantum mechanics is incomplete and that eality exists independently of observation. Bohr’s complementary philosophy and Heisenberg’s uncertainty principle were central to the formulation of the “Copenhagen interpretation,” which became dominant in the 20th century. However, the persistent opposition of scientists like Einstein and Schrödinger inspired generations of physicists to seek a unification between quantum mechanics and relativity, culminating in new theories such as loop quantum gravity and string theory. Thus, the debate between realism and anti-realism remains alive, and philosophy continues to play a crucial role in exploring the new foundations of physics.