Identità elementare e identità genetica. La nozione di “genidentità” in Kurt Lewin

The notion of genidentity, developed by Kurt Lewin in his initial “epistemological” phase, is alternative both to the substantial identity, which is based on the principle of “simple identity” and is not able to give an account of the changes of the same (physical or biological) being over time, and the simple diachronic identity, forced to resort to external properties to ontological determinations of an object, such as the unity of consciousness, or the permanence of linguistic designation. Against these “extensional” qualifications, Lewin proposes an intensional notion of identity whose explanatory power is close in many ways to the prospect of genetic-constitutional “objectual whole” carried out in the first two decades of the twentieth century by Husserl’s phenomenology and Stanisław Leśniewski’s mereology. The identity has for Lewin a relational form, which turns into the different ways of objectual identifying. Time and causality impose themselves therefore as identification criteria among different “genetic series”, which are connected according to an empirical-analogical principle of comparison. So, the ontology expresses the structure of the topological relations among objects, i. e. the set of relationships among the various, unitary and continuous, “world-lines”, within which the physical and biological bodies takes their place.