Weismann Versus Morgan Revisited: Clashing Interpretations on Animal Regeneration

This paper has three principal aims: first, through a detailed analysis of the hypotheses and assumptions underlying Weismann's and Morgan's disagreement on the nature of animal regeneration, it seeks to readdress the imbalance in coverage of their discussion, providing, at the same time, a fascinating case-study for those interested in general issues related to controversies in science. Second, contrary to Morgan's beliefs according to which Weismann employed a speculative and unempirical method of scientific investigation, the article shows that Weismann performed experiments, made observations and proposed 'undogmatic' theories open to refutation. Third, through the reconstruction of Weismann's and Morgan's disagreement, this study illustrates how biology, during the very late nineteenth and early twentieth centuries, was undergoing important changes. I argue that this controversy clearly and convincingly demonstrates how some important epistemic assumptions became increasingly problematic for some members of the younger generations of biologists. At the end of my discussion I will also argue that Weismann and Morgan both had strong well-grounded arguments supporting their conclusions; for this reason I suggest a few factors (taken-for-granted beliefs or assumptions) that could explain why their disagreement was doomed to remain unresolved. In particular, I will analyze their diverse explicative interests, their different theoretical concerns and their distinct use of the available evidence.