Weismann’s three critiques to the inheritance of the acquired characters

Resumen

This paper is a critical discussion of the mode of Weismann’s reasoning in his critique of soft inheritance. The paper shows that far from presenting a parsimonious and straightforward line of reasoning in arguing against the inheritance of acquired characters and in favor of the almightiness of Natural Selection, Weismann’s argument in such connection is threefold as it includes both an empirical case against the IAC and a conceptual attack to that sort of heredity. It is further argued that even at the conceptual level alone two distinct lines of arguing against the viability of the IAC as an evolutionary factor can be distinguished. I will sustain that all in all, none of the arguments proposed by Weismann is conclusive in showing that the IAC is principally impossible, but also that Weismann rightly noticed this when assessing the effectiveness of his critiques. The paper advances a further point: even if the Evolutionary Synthesis seems to be currently expanding in ways not entirely contemplated by Weismann and the Neo-Darwinists, these directions do not convey a vindication of the Lamarckian theory of inheritance and thus don’t fly in the face of Weismann’s empirical argument. Even if they did, that wouldn’t prove Weismann wrong conceptually.

KEY WORDS. Weismann, Darwin, Natural Selection, Inheritance of acquire characters, Evolutionary Synthesis, theories of inheritance, Lamarkism, Neo-Lamarkism, Ockham’s razor, scientific evidence.