This article is a translation into english of a lecture given by paneth in 1931. The content of the work is described by the section titles: (1) the need for epistemological clarification of the fundamental concepts of chemistry, (2) the concept of substance in chemistry, (3) the epistemological standpoint of the ancient atomists, (4) the epistemological position of the concept of element introduced by lavoisier, (5) the double meaning of the chemical concept of element: 'basic substance' and 'simple substance', And (...) (6) the double meaning of other chemical concepts. Sections (4)-(6) are published in the following number of this journal. (staff). (shrink)

Lavoisier defined an element as a chemicalsubstance that cannot be decomposed usingcurrent analytical methods. Mendeleev saw anelement as a substance composed of atoms of thesame atomic weight. These `definitions' doquite different things: Lavoisier'sdistinguishes the elements from the compounds,so that the elements may form the basis of acompositional nomenclature; Mendeleev's offersa criterion of sameness and difference forelemental substances, while Lavoisier's doesnot. In this paper I explore the historical andtheoretical background to each proposal.Lavoisier's and Mendeleev's explicitconceptions of elementhood differed from eachother, and (...) from the official IUPAC definitionof `element' of the 1920s. However, Lavoisierand Mendeleev both subscribed to – andemployed – a deeper notion of a chemicalelement as the component of compound substancesthat (i) can survive chemical change, and (ii)explains the chemical behaviour of itscompounds. (shrink)

The philosophical problem of the utility andmeaning of essences for chemistry cannot beresolved by Wittgenstein's principle thatessence cannot explain use, because use isdisplayed in a field of family resemblances.The transition of chemical taxonomy fromvernacular and mystical based terms to theorybased terms stabilized as a unified descriptivetaxonomy, removes chemical discourse from itsconnection with the vernacular. The transitioncan be tracked using the Lockean concepts ofreal and nominal essences, and the changingpriorities between them. Analyzing propertiesdispositionally, initiating a search forgroundings strengthens the case for (...) a logicalasymmetry between descriptive and explanatorydiscourses. Taxonomy is now driven byexplanatory concepts, but not including thosefrom quantum chemistry. (shrink)

There is now a considerable body of published work on the epistemology of modern chemistry, especially with regard to the nature of quantum chemistry. In addition, the question of the metaphysical underpinnings of chemistry has received a good deal of attention. The present article concentrates on metaphysical considerations including the question of whether elements and groups of elements are natural kinds. It is also argued that an appeal to the metaphysical nature of elements can help clarify the re-emerging controversies among (...) chemists regarding the placement of the elements hydrogen and helium in the periodic system and the question of whether there exists a best form of the periodic table. (shrink)