Propensity , inclination , inclination or tendency towards realization is an objectivistic interpretation of probability proposed by Karl Popper , which can already be found in Peirce's sketches. Popper developed it to solve the problem of interpreting quantum mechanics . In the propensity interpretation, probability is a measure of the tendency of an experiment to produce a certain result.
Opposite the propensity interpretation are in particular the subjectivist theory of Bayesianism , which interprets probabilities as degrees of conviction, and the objective frequency theory , in which probabilities refer to the relative frequency of the occurrence of an event in a sequence of repetitions or in an ensemble of similar processes. Scientific theoretical realists prefer objectivistic theories such as the propensity interpretation, since these make or imply statements about the real world itself and not only about the opinions of a person. In contrast to the frequency interpretation, it can also accept that probabilities also exist for individual cases and explain why they do so.
For Popper, propensities are generalized forces and thus real properties of physical systems. They are relational and do not lie in the things themselves , as is the case with the potentialities of Aristotle: If two cubes are considered, one of which has an imbalance in favor of the side opposite the 6, then the propensity of this weighted cube, in Landing in a strong gravity field after a throw with 6 on top will be significantly higher than the 1/6 observed with the other die. If you try it in a weak gravity field, however, it will be closer to 1/6.
- Antony Eagle: 21 Arguments Against Propensity Analyzes of Probability. In: Knowledge. 60/3, 2004, pp. 371-416.
- JH Fetzer: Peirce and propensities. In: EC Moore (Ed.): Charles S. Peirce and the philosophy of science. Papers from the Harvard sesquicentennial congress, The University of Alabama Press, Tuscaloosa, AL 1993, pp. 60-71.
- David Miller: Critical rationalism. A restatement and defense. Open Court, Chicago / La Salle 1994, ISBN 0-8126-9198-9 , in particular Chapter 9: Objective Probabilities.
- Charles Sanders Peirce : Collected Papers. 2, 1932, pp. 404-414.
- Karl R. Popper: The propensity interpretation of probability. In: British Journal for the Philosophy of Science. X, 37, 1959, doi : 10.1093 / bjps / X.37.25 , pp. 25-42.
- Karl R. Popper: A world of propensities. Mohr Siebeck, Tübingen 1995, ISBN 3-16-146208-4 ( limited preview in the Google book search).
- Karl R. Popper: The quantum theory and the schism of physics . From the postscript on the logic of research III. Mohr Siebeck, Tübingen 2001, ISBN 3-16-147568-2 ( limited preview in the Google book search).
- Christina Schneider: Two interpretations of objective probability. On the ambiguity of Popper's conception of propensities. In: Philosophia naturalis . 31/1, 1994, pp. 107-131.
- The Propensity Interpretation of the Calculus of Probability and of the Quantum Theory . Popper, Karl . In Observation and Interpretation . Buttersworth Scientific Publications, Korner & Price (eds.) 1957. pp. 65-70.
- Alan Hájek: Interpretations of Probability, 3.4. Propensity Interpretations. In: Edward N. Zalta (Ed.): Stanford Encyclopedia of Philosophy .
- David Miller: Popper's Contributions to the Theory of Probability and Its Interpretation ( Memento of October 25, 2012 in the Internet Archive ) (PDF; 171 kB), Draft, appears in: Jeremy Shearmur / Geoffrey Stokes (eds.): The Cambridge Companion to Popper , Cambridge: Cambridge University Press.