Antoine Laurent Lavoisier, the father of modern chemistry and the intellectual disciple of Condillac, proposed in the Methode de nomenclature chymique of 1787 that by structuring the language of chemistry according to Condillac's theories of perfect, immediate, analytic and purely denotative language as described in the Logique, he would produce a chemical revolution (the characterization is his own in a letter to Benjamin Franklin).' For Lavoisier, a nomenclature is a denotative field understood to operate in opposition to the connotative, poetic, rhetorical and indeterminate qualities of the common language, as had already been suggested in Condillac's Treatise on Sensations (1753). Working inside the nomenclature, the chemist would not indulge in pure speculation, but would be forced to fill in the blanks already made visible by the denotative grid of the nomenclature. These blanks, for all who learn and add to the nomenclature, would prescribe the work still be done. But for Lavoisier, scientific work is not only carried out inside the nomenclature. His chemist operates as well with and within common language. The scientific nomenclature provides him with conceptual rigor, but the possibility of a balancing speculative dynamism is equally important. Otherwise, there is no way to recognize and correct mistakes, in other words, no way to theoretically innovate. By combining these two sorts of language, the chemist produces not statements whose truth is guaranteed in advance, but plausible propositions or hypotheses. A scientific language thus is not just a nomenclature, but the embedding of a