Among the philosophical issues raised by quantum theory, the alleged indeterminism of quantum-physical phenomena, as opposed to the determinism of classical physics, has stood at the center of discussion. There are various other much-debated problems which are directly or indirectly related to this issue or, more generally, the probabilistic character of quantum theory. Less attention has been paid to the questions of the stability of atoms and the specificity of their properties, which quantum theory was primarily designed to resolve. I argue that the indeterminism of quantum theory becomes less intriguing and can be better comprehended when seen in the light of these questions - or briefly, that “stability implies indeterminism, or chance.” Chance, in this respect, appears as an objective and legitimate mode of succession of otherwise stable and discrete well-determined states of certain physical systems.Among the philosophical issues raised by quantum theory, the alleged indeterminism of quantum-physical phenomena, as opposed to the determinism of classical physics, has stood at the center of discussion. There are various other much-debated problems which are directly or indirectly related to this issue or, more generally, the probabilistic character of quantum theory. Less attention has been paid to the questions of the stability of atoms and the specificity of their properties, which quantum theory was primarily designed to resolve. I argue that the indeterminism of quantum theory becomes less intriguing and can be better comprehended when seen in the light of these questions - or briefly, that “stability implies indeterminism, or chance.” Chance, in this respect, appears as an objective and legitimate mode of succession of otherwise stable and discrete well-determined states of certain physical systems.

Annals of the Japan Association for Philosophy of ScienceJan 1, 19770 citations

The Empirical Basis of Quantum Theory

Bas C. van Fraassen

If the world is not deterministic, then at the very least, some individual events just happen ’by chance’. But the frequency of such events and correlations between them could be subject to constraints, whether local or non‐local. Hans Reichenbach introduced a principle weaker than determinism but non‐trivial: that every positive correlation should be traceable to a common cause (defined in terms of temporal precedence plus certain probabilistic relations). This principle turns out to imply the Bell Inequalities, which quantum theory violates. This chapter discusses the logical relations between indeterminism, common cause models, the Bell Inequalities, non‐contextual hidden variable models, and various concepts of locality and non‐locality, as well as the experiments designed to reveal the predicted violations.If the world is not deterministic, then at the very least, some individual events just happen ’by chance’. But the frequency of such events and correlations between them could be subject to constraints, whether local or non‐local. Hans Reichenbach introduced a principle weaker than determinism but non‐trivial: that every positive correlation should be traceable to a common cause (defined in terms of temporal precedence plus certain probabilistic relations). This principle turns out to imply the Bell Inequalities, which quantum theory violates. This chapter discusses the logical relations between indeterminism, common cause models, the Bell Inequalities, non‐contextual hidden variable models, and various concepts of locality and non‐locality, as well as the experiments designed to reveal the predicted violations.

Oxford University Press eBooksSep 26, 19911 citation

Determinism and Probability

Series on the foundations of natural science and technologyNov 1, 20250 citations

Interference, recoil, and uncontrollable interaction

Ole Ulfbeck

When the initial state in a collision involves indeterminate momenta, the conservation law for momentum no longer applies to the individual event with a sharpness beyond the indeterminacy. As a consequence, there are collisions that are recoilless in the sense that the state of one of the quanta is unchanged by the collision while the other quantum emerges in a superposition of momenta. Recoilless collisions that avoid entanglement are basic for experiments studying coherence effects for individual quanta involving interactions of the quantum with reflectors or diaphragms. The idea that in interference experiments there is an inevitable recoil that can be made unobservable by firmly bolting the reflector or diaphragm to a solid support is false since in interference with individual quanta there $\mathit{is}$ no recoil to control. The highly quantal character of the reflector or diaphragm in the interference experiment apparently went unnoticed in the conception of complementarity.When the initial state in a collision involves indeterminate momenta, the conservation law for momentum no longer applies to the individual event with a sharpness beyond the indeterminacy. As a consequence, there are collisions that are recoilless in the sense that the state of one of the quanta is unchanged by the collision while the other quantum emerges in a superposition of momenta. Recoilless collisions that avoid entanglement are basic for experiments studying coherence effects for individual quanta involving interactions of the quantum with reflectors or diaphragms. The idea that in interference experiments there is an inevitable recoil that can be made unobservable by firmly bolting the reflector or diaphragm to a solid support is false since in interference with individual quanta there $\mathit{is}$ no recoil to control. The highly quantal character of the reflector or diaphragm in the interference experiment apparently went unnoticed in the conception of complementarity.

Physical Review AJul 30, 20140 citations

\mathit{is}

no recoil to control. The highly quantal character of the reflector or diaphragm in the interference experiment apparently went unnoticed in the conception of complementarity.