The article addresses one of the central difficulties in the methodology of science: the comparison of theoretical constructions situated at different stages of development. Philosophy of science has developed a broad corpus of criteria for theory evaluation—explanatory power, empirical support, falsifiability, retrospective reconstruction, predictive productivity, intertheoretical translation, research fertility, resilience to counterexample, and transparency of assumptions. However, the practical procedure of theory comparison often relies predominantly on a single axis—either the rank of theoretical claims or the breadth of explanatory scope. As a result, a mature theory with a developed body of work, a stable vocabulary, and a long history of testing acquires a hidden advantage over an early hypothesis or research program, even when the object of comparison calls for a different and more commensurate procedure. The paper substantiates the thesis that two independent axes of methodological evaluation must be distinguished: the rank of theoretical claims and the stage of maturity of the theoretical construction. It is shown that proper intertheoretical comparison requires commensurability along both axes simultaneously. On this basis, a scheme of stages in the formation of theory is proposed—from problem formulation and hypothesis to conceptual scheme, research program, developed theory, and mature predictively loaded theory. For each stage, its own checkpoints, type of scientific value, and grounds for transition to the next stage are formulated. The paper additionally analyzes the influence of maturity asymmetry on intertheoretical relations. It is shown that, without a specific adjustment for the stage of development, comparison begins to measure simultaneously both the explanatory power of a theory and the accumulated volume of research infrastructure. Such asymmetry generates two opposing methodological risks: the premature exclusion of a productive line in its formative phase and the prolonged retention of a conceptual scheme that has exhausted its own explanatory productivity. Historical cases of continental drift, plate tectonics, phlogiston, as well as discussions of the relations between classical and molecular genetics, are used as material for clarifying these risks. The novelty of the article lies in the systematic substantiation of the commensurability of maturity stage as an independent condition for proper intertheoretical evaluation. The proposed scheme makes it possible to clarify the status of comparison, competition, translation, integration, reduction, and inclusion between theories, and also strengthens evaluative discipline in cases where concepts of different ages, different corpus densities, and different testing burdens are being compared.
Alena Petina (Mon,) studied this question.