Abstract

Through a detailed explication of Bernard Bolzano's semantics of natural kind terms, I elucidate why and to what extent he should be recognized as a remarkable anticipator of semantic externalism. Bolzano deals with kind terms in a brief sub-section of the first volume of his Theory of Science. He divides such terms into two sub-categories, roughly corresponding to organic and inorganic kinds. It is Bolzano's account of inorganic kind terms, such as ‘gold’, that confers on him the status of an anticipator of semantic externalism. He argues that ‘gold’ may be used in a way such that the superficial attributes that language users associate with it merely serve to enable them to recognize its instances. They do not, however, constitute the idea designated by the term nor do they determine its extension. Instead, the term designates an idea representing gold's unknown inner attributes, which are causally responsible for its superficial attributes.