The bulk of Duhem's writing which bears on the understanding of mixtures suggests he adopted an Aristotelian position which he opposed only to the atomic view. A third view from antiquity-that of the Stoics-seems not to be taken into account. But his lines of thought are not always as explicit as could be wished. The Stoic view is considered here from a perspective which Duhem might well have adopted. This provides a background against which his somewhat unorthodox Aristotelianism might be (...) understood. (shrink)

We can distinguish ‘mechanical’ in the strict sense of the mechanical philosophers from ‘mechanical’ in the common sense. My claim is that Boyle's experimental science owed nothing to, and offered no support for, the mechanical philosophy in the strict sense. The attempts by my critics to undermine my case involve their interpreting ‘mechanical’ in something like the common sense. I certainly accept that Boyle's experimental science was productively informed by mechanical analogies, where ‘mechanical’ is interpreted in a common sense. But (...) this leaves my original claim untouched and, in the main, unchallenged.Keywords: Boyle; Mechanism; Mechanical philosophy; Corpuscular philosophy; Reductionism. (shrink)

Summary Robert Boyle is remembered largely for his integration of experiment and the ?mechanical philosophy?. Although Boyle is occasionally elusive as to what he means precisely by the ?mechanical philosophy?, it is clear that a major portion of it concerned his corpuscular theory of matter. Historians of science have traditionally viewed Boyle's corpuscular philosophy as the grafting of a physical theory onto a previously incoherent body of alchemy and iatrochemistry. As this essay shows, however, Boyle owed a heavy debt to (...) a longstanding alchemical theory that postulated the corpuscular make-up of metals and various reagents. I have elsewhere argued in a general way for Boyle's debt to alchemical corpuscular theory, but in the present essay I show one of his precise sources?namely the Wittenberg medical professor Daniel Sennert (1572?1637). In his youth Boyle wrote a treatise on corpuscularianism, Of the Atomicall Philosophy, that borrowed heavily from Sennert without acknowledgement. Later works, such as The Sceptical Chymist, elaborate on these borrowings. This discovery shows that we cannot view Boyle's corpuscular philosophy as an imposition of physics on chemistry: instead, it appears that it originally grew out of chemistry itself. The discovery also throws an interesting light on Boyle's attitude toward sources. (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.

What, precisely, is `salt'? It is a certainwhite, solid, crystalline, material, alsocalled sodium chloride. Does any of that solidwhite stuff exist in the sea? – Clearly not.One can make salt from sea water easily enough,but that fact does not establish thatsalt, as such, is present in brine. (Paper andink can be made into a novel – but no novelactually exists in a stack of blank paper witha vial of ink close by.) When salt dissolves inwater, what is present is no (...) longer `salt' butrather a collection of hydrated sodium cationsand chloride anions, neither of which isprecisely salt, nor is the collection. Theaqueous material in brine is also significantlydifferent from pure water. Salt may beconsidered to be present in seawater, but onlyin a more or less vague `potential' way.Actually, there is no salt in the sea. In bothancient and modern treatments of otherimportant chemical concepts, including thenotions of `element', related complication,especially polysemy (terms with multiplemeanings), also occurs.In a recent paper, Paul Needham discussed the(predicable) properties of chemical substances,phases, and solutions. He provided a valuablecharacterization of cases in which severalquantities occupy the same space. He alsoconcluded that solution properties are not`intensive', because solvent and solute do nothave parts in common. He tacitly assumed thatingredients are not altered by their inclusionin a solution. This may be the case in somespecial cases (deutero-benzene dissolved inbenzene, say) but is not true in general – andcertainly does not apply to the case of brine,which Needham used as an example – since theions that exist in the solution, and also theaqueous material there, are quite differentfrom the pure ingredients used in making thesolution. An adequate theory of wholes andparts (mereology) must take into account thatwhen individuals enter combinations ofinteresting sorts they no longer are the verysame individuals that existed prior to thecomposition. It appears that no such formaltheory now actually exists. (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)

In this article we critically evaluate Robin Le Poidevin's recent attempt to set out an argument for the ontological reduction of chemistry independently of intertheoretic reduction. We argue, firstly, that the argument he envisages applies only to a small part of chemistry, and that there is no obvious way to extend it. We argue, secondly, that the argument cannot establish the reduction of chemistry, properly so called.

The Aristotelian distinction between actual and potential presence of a substance in a mixture forms part of a conception of mixture which stands in contrast to atomist and Stoic theories as propounded by the ancients. But the central ideas on which these theories are built need not be combined and opposed to one another in precisely the ways envisaged by these ancient theories. This is well illustrated by Duhem, who maintained the Aristotelian idea that the original ingredients are only potentially, (...) and not actually, present in a mixture, but who sided with the Stoics and against Aristotle on the possibility of co-occupancy. I have argued that the Stoic theory cannot dispense with some such notion as the Aristotelian conception of potentiality in allowing the elements to be actually present in a mixture. Here I suggest that some such Aristotelian notion must be at work in a more modern atomic conception of matter if this is to allow elemental substances to be actually present in compounds, which I think is how compounds are usually understood. Analogous issues arise regarding the status of solutions and their components. (shrink)