Of Snails and Horsetails

Abstract

The problem of generalization was a vexing one in anatomical investigations: when was it legitimate to generalize from one individual observed or dissected at a given time to the same individual at different times, or to individuals of the same species, or even to individuals from different species altogether? Views on these matters varied widely from the Renaissance to the Enlightenment and guided different research programs based on opposite assumptions. A growing basis of empirical results made anatomists aware of the dangers of hasty generalizations. The problem of reproduction in animals and plants led to especially startling findings that shattered naïve assumptions about the uniformity of nature. Yet, from a multitude of seemingly unpredictable results, new, equally unpredictable patterns and analogies emerged, leading to the discovery of sexual reproduction in plants, for example. Snails and horsetails proved especially challenging in this context.