Abstract

Summary A famous debate between John Ray, Joseph Pitton de Tournefort and Augustus Quirinus Rivinus at the end of the seventeenth century has often been referred to as signalling the beginning of a rift between classificatory methods relying on logical division and classificatory methods relying on empirical grouping. Interestingly, a couple of decades later, Linnaeus showed very little excitement in reviewing this debate, and this although he was the first to introduce the terminological distinction of artificial vs. natural methods. In this paper, I will explain Linnaeus's indifference by the fact that earlier debates were revolving around problems of plant diagnosis rather than classification. From Linnaeus's perspective, they were therefore concerned with what he called artificial methods alone ? diagnostic tools, that is, which were artificial no matter which characters were taken into account. The natural method Linnaeus proposed, on the other hand, was not about diagnosis, but about relations of equivalence which played a vital, although largely implicit role in the practices of specimen exchange on which naturalists relied to acquire knowledge of the natural world