"An Analysis of Mendel's Two Hybridist Theories and their Intertheoretical Relationships"

LORENZANO, PABLO

Folia Mendeliana

Moravian Museum Brno

Lugar: Brno; Año: 2022 vol. 58 p. 45 - 72

0085-0748

Based on astatistical analysis of his experiments, which was a novelty for the traditionof "horticulturalists" (or "plant breeders") as well as for the tradition of "hybridists", andseeking a "generally applicable law governing the formation and development ofhybrids" (Mendel 1865: 3), Mendel states "the law of development/evolutionfound for Pisum" (Mendel 1865: 32). When he tries to provide the "foundation and explanation" (Mendel1865: 32) of the law of formation and development of hybrids, he does it interms of the production and behavior of egg cells and pollen cells, and,ultimately, in terms of the nature and behavior of what he calls "elements"(Mendel 1865: 41) or "cell elements" (Mendel 1865: 42). Moreover,Mendel recognizes the existence not just of hybrids that behave like those of Pisum ‒ i.e., of "variable hybrids" ‒ but also of hybrids that "remain perfectlylike the hybrid and continue constant in their offspring" (Mendel 1865: 38) and "acquire the status of new species" (Mendel 1865: 40) ‒ i.e., of "constant hybrids" (Mendel 1869: 27-28,31). The law that wouldgovern the behavior of constant hybrids would also find its foundation andexplanation in terms of the nature and behavior of elements (or cell elements).Mendel´s hybridism consists of two theories: a theory that moves on a more "empirical" level, according to Schleiden´s first "special guiding maxim", the "Maxim of the history of development/evolution" (Schleiden 1849: 141,142, 146),which can be called "Mendel´s theory of the development/evolution of hybrids" (DEH), and a theory that moves on a more "theoretical" level, according to Schleiden´s second "special guiding maxim",the "Maxim of the autonomy of cells in plants" (Schleiden 1849: 146, 148),which can be called "Mendel´s theory of the cellular foundation of thedevelopment/evolution of hybrids" (CFH).The paper aims to present an analysis of these two theories and their intertheoretical relationships, carried out within theframework of the so-called Metatheoretical Structuralism (Balzer, Moulines & Sneed 1987).