Comparing theories with the Ising model of explanatory coherence.

[Correction Notice: An Erratum for this article was reported in Vol 29(3) of Psychological Methods (see record 2025-28068-002). In the article, the copyright attribution was incorrectly listed, and the Creative Commons CC BY 4.0 license disclaimer was incorrectly omitted from the author note. The correct copyright is "© 2023 The Author(s)," and the omitted disclaimer is below: Open Access funding provided by University College London: This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0; https://creativecommons.org/licenses/by/ 4.0). This license permits copying and redistributing the work in any medium or format, as well as adapting the material for any purpose, even commercially.] Theories are among the most important tools of science. Lewin (1943) already noted "There is nothing as practical as a good theory." Although psychologists discussed problems of theory in their discipline for a long time, weak theories are still widespread in most subfields. One possible reason for this is that psychologists lack the tools to systematically assess the quality of their theories. Thagard (1989) developed a computational model for formal theory evaluation based on the concept of explanatory coherence. However, there are possible improvements to Thagard's (1989) model and it is not available in software that psychologists typically use. Therefore, we developed a new implementation of explanatory coherence based on the Ising model. We demonstrate the capabilities of this new Ising model of Explanatory Coherence (IMEC) on several examples from psychology and other sciences. In addition, we implemented it in the R-package IMEC to assist scientists in evaluating the quality of their theories in practice. (PsycInfo Database Record (c) 2024 APA, all rights reserved).