Paul Needham

Late nineteenth‐century opponents of atomism questioned whether the evidence required any notion of an atom. In this spirit, Duhem developed an account of the import of chemical formulas that is clearly neutral on the atomic question rather than antiatomistic. The argument is supplemented with specific inadequacies of atomic theories of chemical combination and considerably strengthened by the theory of chemical combination provided by thermodynamics. Despite possible counterevidence available at the time, which should have tempered some of Duhem's concluding remarks, there was no atomic theory of chemical combination, which is wholly a product of the twentieth century. †To contact the author, please write to: Department of Philosophy, University of Stockholm, SE‐106 91 Stockholm, Sweden; e‐mail: [email protected].

‘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

Eric Scerri has proposed an account of how reduction might be understood in chemistry. He claims to build on a general aspect of Popper's views which survives his otherwise heavy criticism, namely adherence to actual scientific practice. This is contrasted with Nagel's conception, which Scerri takes to be the philosopher's standard notion. I argue that his proposal, interesting though it is, is not so foreign to ideas in the tradition within which Nagel wrote as Scerri would have us believe. Moreover, actual scientific practice can be commandeered in support of a holistic conception which Popper contrasted with what he saw as the admirable strivings towards reduction in science.

Some points are made about substance properties in their role of introducing mass terms. In particular, two conditions of distributivity and cumulativity of mass predicates expressing these properties are not the independent pair they first appear to be. A classification of macroscopic substance concepts is developed. This needs to be complemented in some way by the introduction of a modal qualification reminiscent of Aristotle's distinction between actual and potential presence of substances in a mixture. Consideration of the latter feature has prompted Joe Earley to raise the question of whether there is any salt in the sea. I try to argue that there is.

Despite all the criticism showered on Nagel’s classic account of reduction, it meets a fundamental desideratum in an analysis of reduction that is difficult to question, namely of providing for a proper identification of the reducing theory. This is not clearly accommodated in radically different accounts. However, the same feature leads me to question Nagel’s claim that the reducing theory can be separated from the putative bridge laws, and thus to question his notion of heterogeneous reduction. A further corollary to the requirement that all the necessary conditions be incorporated in an adequate formulation of the putative reducing theory is that the standard example of gas temperature is not reducible to average molecular kinetic energy. As originally conceived, Nagel’s conception of reduction takes no account of approximate reasoning and this failure has certainly restricted its applicability, perhaps to the point of making it unrealistic as a model of reduction in science. I suggest approximation can be accommodated by weakening the original requirement of deduction without jeopardizing the fundamental desideratum. Finally, I turn to briefly consider the idea sometimes raised of the ontological reducibility of chemistry.

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.

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

Two inter-linked theses are defended in this paper. One is the Duhemian theme that a rigid distinction between physical and chemical properties cannot be upheld. Duhem maintained this view not because the latter are reducible to the former, but because if physics is to remain consistent with chemistry it must prove possible to expand it to accommodate new features, and a rigid distinction would be a barrier to this process. The second theme is that naturally occurring isotopic variants of water are in fact distinct substances, and naturally occurring samples of water are mixtures of these substances. For most practical purposes it is convenient to treat protium oxide, deuterium oxide, and so on, as the same chemical substance, but to insist on this as a matter of principle would stand in conflict with the first thesis.

In a recent article in this journal (Foundations of Chemistry, 7 (2005), 125–148) Lombardi and Labarca call into question a thesis of ontological reduction to which several writers on reduction subscribe despite rejecting a thesis of epistemological reduction. Lombardi and Labarca advocate instead a pluralistic ontology inspired by Putnam’s internal realism. I suggest that it is not necessary to go so far, and that a more critical view of the ontological reduction espoused by the authors they criticise circumvents the need to resort to their radical alternative.

Robert Deltete and Anastasios Brenner have provided a thorough examination of my translation of Duhem’s Le mixte et la combinaison chimique (1902) and associated essays. I am very grateful for their efforts and gratified that such competent reviewers should be generally positive. They provide an overview of relevant aspects of Duhem’s life and work, which may serve to introduce him to readers of this journal and promote interest in Duhem studies. They also raise and answer some questions about the interpretation and evaluation of Duhem’s work, make some points of criticism of my choice of material and question certain points of translation. The editor has suggested that I make a response, and I shall take up some issues in these three areas. Since Duhem’s views play a central role in the development of the concept of chemical substance which I have worked on in recent years, I will make several references to my own publications.

A general analysis of reduction is as important to critics who deny reductionist claims as to their advocates. Nagel’s analysis continued to find favour amongst such critics after advocates sought alternatives—often attempted generalisations of perceived specific paradigm cases of reductive identification, such as temperature and mean molecular kinetic energy. The pros and cons of Nagel’s account are discussed, but the difficulties are not satisfactorily overcome by approaches advanced by Causey, Spector and Beckermann. Although no general account is settled upon, temperature is considered in some detail and found not to provide the paradigm case of reduction taken to motivate these alternatives.

Are there events? If so, how are they to be conceived? A line of argument motivating ontological commitment to what I prefer to call processes is presented, drawing primarily on the development of the elementary understanding of thermal processes, but pointing to a broader view by analogical extension. Suggestions are made for an approach to the mereological structure of processes, and some comments are offered of linguistic distinctions sometimes applied to processes and to modal features of events mentioned in the literature.

Davidson's account of singular causal statements as expressing relations between events together with his views on event identity lead to inferences involving causal statements which many of his critics find counterintuitive. These are sometimes said to be avoided on Kim's view of events, in terms of which this line of criticism is often formulated. It is argued that neither Davidson nor Kim offer a satisfactory account of events — an essential prerequisit for the relational theory — and an account of singular causal statements in terms of a modal sentential connective is advocated in place of the relational view. Such an account suffices to block the counterintuitive inferences without needing to resort to a theory of events. It is suggested that a theory of events might be built upon a connective account of singular causal statements, but no such theory is presented here

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.

ABSTRACT The idea that the extension of a chemical substance is fixed by determining what stands in the relation of being the same substance to a paradigm sample plays a substantial role in chemistry, and procedures of identification that don’t make direct use of the method can be traced back to ones that do. But paradigm samples are not typically selected by ostension, as in Putnam’s version of this procedure. The relevance of ostension is questioned after a discussion of the establishment of paradigm specimens in the analysis of some contents of crude oil and an examination of the general features of the same-substance relation that takes into account the temporal dependency and the consequent role of characteristic features of substances. 1Introduction 2Some Formal Properties of the Same-Substance Relation 3Characteristic Properties and Paradigm Samples 4Naming Substances Old and New 5Some Points of Comparison with Temperature 6Summary and Conclusion

Chemistry deals with substances and their transformations. School chemistry provides a picture of this in terms of small balls called atoms and ball-and-stick structures called molecules which, despite its crudity, has been taken to justifiably reflect a reductionist conception of macroscopic concepts like the chemical substances and chemical reactions. But with the recent interest in chemistry within the philosophy of science, an extensive and determined criticism has developed of the idea that the macroscopic world has been, or is likely to be, reduced to microscopic theory. From this perspective, it is of interest to see macroscopic ontology treated autonomously. I try to take a first few steps towards spelling this out. It involves recognising entities falling into two broad categories: continuants-things which can have different properties at different times — and processes — things whose temporal parts may have different features, but which themselves stand in contrast to continuants in this respect. The character of each and their interrelations depends on their mereological structure of parts, the exploration of which is one of the prime purposes of the paper.

The history of the hydrogen bond provides a good example of the of an important chemical concept. It illustrates the interplay between empirical and theoretical approaches to the problem of delimiting what has proved to be quite an elusive notion, with chemists whittling away at the particular sorts of case with a view to obtaining a precise, unitary concept. Even though there is a return to a more theoretically inspired notion in more recent research, empirical characterisations remain a feature of the report of a Task Group recently set up by the IUPAC to reconsider the definition of the hydrogen bond, and this situation—by no means unusual for chemical concepts and principles—is unlikely to change in the foreseeable future. These developments are reviewed in this paper, which includes an extended discussion of the enormous significance hydrogen bonding has for the philosopher’s standard example of a “natural kind”, water. There is little to suggest a reduction to what philosophers of physics are pleased to call fundamental principles, and the details raise further questions about what essentialists could possibly have in mind when talking about the microscopic essence of water

Duhem is often described as an anti-realist or instrumentalist. A contrary view has recently been expressed by Martin (1991) (Pierre Duhem: Philosophy and History in the Work of a Believing Physicist (La Salle, IL: Open Court)), who suggests that this interpretation makes it difficult to understand the vantage point from which Duhem argues in La science allemande (1915) that deduction, however impeccable, cannot establish truths unless it begins with truths. In the same spirit, the present paper seeks to establish that Duhem is at any rate not the kind of anti-realist he is often presented as being, and that his views are like those Quine sees fit to call realist. An interpretation of Duhem's views on explanation and precision in science, and their bearing on the epistemological status of theory, is advanced which leads naturally into his critique of conventionalism. His attitude towards atomism, which should not be judged from a post-1925 perspective, is considered part of the unified view he strove after and appropriately called Duhem's physicalism, standing in contrast to the kind of reductionist conception usually associated with atomism.