‘Water is H 2 O’ is naturally construed as an equivalence. What are the things to which the two predicates ‘is water’ and ‘is H 2 O’ apply? The equivalence presupposes that substance properties are distinguished from phase properties. A substance like water (H 2 O) exhibits various phases (solid, liquid, gas) under appropriate conditions, and a given (say liquid) phase may comprise several substances. What general features distinguish substance from phase properties? I tackle these questions on the basis of (...) an interpretation of a theorem of thermodynamics known as Gibbs' phase rule which systematically relates these two kinds of feature of matter. The interpretation develops the idea that the things substance and phase predicates apply to are quantities of matter which sustain mereological relations and operations and exploits these mereological features in distinguishing the two kinds of property. Gibbs' phase rule is a macroscopic principle applicable for macroscopic intervals of time. Bringing intervals of time into the picture calls for a more detailed consideration of the relation between macroscopic equilibria and the corresponding dynamic equilibria at the microlevel and throws into question the simple idea that quantities can always be regarded as collections of molecules. The account provides some insight into how the continuous, macroscopic conception of matter (‘gunk’) is reconciled with the discrete microscopic conception and illuminates the interpretation of substances present in mixtures. (shrink)

What are the criteria determining the individuation of chemical kinds? Recent philosophical discussion, which puts too much emphasis on microstructure, seems to presuppose a reductionist conception not motivated by the scientific facts. The present article traces the development of the traditional notion of a substance with the rise of modern chemistry from the end of the 18th century with a view to correcting this speculative distortion.

This paper takes up issues related to the notion of chemical substances arising from their mereological and modal features. Related notions are elements and compounds, into which substances are sub-divided, and the general notion of mixture, which as a special case might involve several substances, but covers other cases too. These are essentially macroscopic concepts. Some of the chemical arguments for this claim have been presented elsewhere. The present paper is a metaphysical treatment of matter as categorised by the major (...) chemical concepts bearing on distinctions between homogeneous and heterogeneous matter, and between a single and several substances. (shrink)

According to microessentialism, it is necessary to resort to microstructure in order to adequately characterise chemical substances such as water. But the thesis has never been properly supported by argument. Kripke and Putnam, who originally proposed the thesis, suggest that a so-called stereotypical characterisation is not possible, whereas one in terms of microstructure is. However, the sketchy outlines given of stereotypical descriptions hardly support the impossibility claim. On the other hand, what naturally stands in contrast to microscopic description is description (...) in macroscopic terms, and macroscopic characterisations of water are certainly possible. This suffices to counter the claim that microdescriptions are necessary. Whether it counters the impossibility claim depends on whether all macroscopic descriptions are stereotypical (stereotypical descriptions presumably being macroscopic). In so far as systematic import of “stereotypical” can be determined, it would seem not. But some macroscopic characterisations have definite affinity with everyday knowledge, which presumably stands in conflict with the spirit of the impossibility claim. Since what is characterised are properties expressed by predicates like “is water”, the necessity of identity has no bearing here, and matters of interpretation pose problems for claims to the effect that science fixes the extension of “water” as ordinarily understood. (shrink)

The rejection of the idea that the so‐called Duhem‐Quine thesis in fact expresses a thesis upheld by either Duhem or Quine invites a more detailed comparison of their views. It is suggested that the arguments of each have a certain impact on the positions maintained by the other. In particular, Quine's development of his notion of ontological commitment is enlisted in the interpretation of Duhem's position. It is argued that this counts against the instrumentalist construal usually put on what Duhem (...) says about approximation and historical continuity. (shrink)

This classic work in the philosophy of physical science is an incisive and readable account of the scientific method. Pierre Duhem was one of the great figures in French science, a devoted teacher, and a distinguished scholar of the history and philosophy of science. This book represents his most mature thought on a wide range of topics.