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Synopsis of François Dagognet, ‘Sur Lavoisier: Présentation du Discours préliminaire’

[‘On Lavoisier and the Preliminary Discourse to his Elements of Chemistry (1789)’]

CpA 9.13:178–194

François Dagognet (born 1924) studied under Canguilhem and trained in both philosophy and several branches of science, including medicine, chemistry and geology. By the time he came to write this piece on the chemist Antoine Lavoisier for the Cahiers pour l’Analyse he had written several books, including studies of ‘biological philosophy’, Bachelard (1965), Pasteur (1967), and a book based on his doctoral thesis: La Raison et les remèdes (1964). His many and varied later books include Pour une théorie générale des formes (1975) and Le Nombre et le lieu (1984).

Dagognet’s contribution to the Cahiers provides an overview of several distinctive aspects of Lavoisier’s work, in particular his neo-Cartesian concern for order and simplicity, and his contribution to the development of a formal symbolic system for the representation of chemical substances. In 1969, Dagognet returned to Lavoisier and the classification of chemical elements in his book Tableaux et langages de la chimie.

Dagognet begins his article with a characterisation of Lavoisier’s general philosophical approach, after Condillac, as that of a ‘reworked Cartesianism: inverted but thereby conserved’ (CpA 9.13:178). Lavoisier assumes that nature is organised by a well-intentioned God in terms that are simple, clear, and distinct, and that in order to read the book of nature we need only eliminate the obstacles (received ideas; passions and prejudices) that prevent us from gaining direct access to things themselves (CpA 9.13:179).

Dagognet points out that Lavoisier’s work on chemical nomenclature (along with much of his other scientific work) built on the innovations of his predecessors. By 1782 Guyton de Morveau had established several principles that would underlie the newly systematised practice of naming chemical substances: a name should be simple, based on a fixed and unchanging (i.e. dead) language, be formed of a basic root plus variable prefixes and suffixes, and remain free of any direct ‘substantial’ link to the substance it names. Guyton requires, in short, that a chemical nomenclature allow for the creation of ‘many neologisms’ on the basis of only a ‘small number of letters’ (CpA 9.13:181-182).

Lavoisier’s Discours préliminaire will affirm the same principles, and adapt them in order to pursue a more general project of formal classification. Lavoisier’s main contribution to his discipline, Dagognet argues, was to re-think and simplify, in strictly rationalist terms, the results acquired by the ‘passionate explorations’ of his empiricist predecessors (CpA 9.13:185). He conceives of every substance as the literal sum of the more elementary substances it contains, such that a substance classed as ‘AB’ might be understood as the sum of two elementary substances A + B (CpA 9.13:186) – for instance, water understood as a composite of oxygen and hydrogen. (This invites some comparison with the logic underlying Boole’s approach to symbolic notation, CpA 10.2).

In keeping with his Cartesian principles, Lavoisier assumes that ‘the universe is divided in a regular series of elements, and chemistry evokes a natural mathematics of order, a science of numbers or line’ (CpA 9.13:186). Lavoisier’s analysis of the mechanics of combustion, in particular, persuades him that all composite substances are created through ‘juxtaposition or agglomeration’, just as, in a language, words are made up of letters. Lavoisier aims to formalise a system of scientific classification in which chemical elements correspond to the letters of nature’s alphabet (CpA 9.13:187). The chemist will thus ‘undertake the work of [divine] creation in reverse: rather than engender complex beings, he will break them asunder and refer back to their roots, to the primitive alphabet with which everything seems to have been written’ (CpA 9.13:179). Extending this reductive-analytical approach to calorimetric measurements, Lavoisier demonstrates that changes of form or state are always linked to the absorption or loss of a certain amount of heat, an amount that might be measured in ultimately mechanical terms (CpA 9.13:187-188). In the end, ‘the universe in its totality spreads itself out in front of us, in an entirely reducible’ series of elements and combinations. Substances are purged of the noumenal qualities (e.g. their essential tincture, their affinities with other substances, etc.) that earlier chemists had preserved and sought to grasp: ‘from now on, substances can be freely made and unmade, and no longer hide any qualities [...]. Never was the world laid more low [jamais le monde ne fut plus abaissé]’, or nature more brutally disenchanted.

Unlike his predecessors, Lavoisier thus avoids the temptation to establish a table of the ‘affinities’ that might seem to relate certain substances to others with which they share an essential ‘sympathy’. He is sceptical of affinity because it introduces obscure forces into an otherwise clear and distinct domain, thereby inhibiting a strictly ‘additive’ and mechanical understanding of composite substances. Precisely because he is ‘absolute determinist, an adept of strict mechanics’, Lavoisier insists on the unconditional combinatory freedom of the elements, i.e. the freedom of ‘any given element, in principle, to associate with any and all other elements’ (CpA 9.13:191).

Dagognet concludes his article with an afterword devoted to the general problem, inherited from Lavoisier, of formal chemical notation. Contemporary organic chemistry has come to recognise and classify more than a million distinct substances (CpA 9.13:192). In keeping with its Lavoisian inspiration, chemical nomenclature continues to try to ‘represent and enclose a world that is getting bigger and bigger in or under signs that are smaller and smaller’, via the multiplication of prefixes (mono-, di-, tri-, iso-, cyclo-...) and suffixes (-ol for the alcohols, -ane for the alkanes, etc.). ‘A million baptisms’ have been carried out, based on the ramified organisation of a domain that lends itself exceptionally well to rigorous symbolic classification [la symbolique vocale]. ‘In chemistry, no more than any other domain, perhaps, there is nothing that cannot be said or expressed: Lavoisier was the first to understand this clearly.’ In this sense, chemistry ‘defines an island of resistance in a philosophical sea’ that otherwise rages against the orderly representation of symbols and formulae. Whereas classification likewise applies to the neighbouring field of biology, there ‘words can only evoke or designate, they cannot signify; they slide over the beings that they conceal. In chemistry, by contrast, they condense and deliver’ the substances they represent (194).

Lavoisier’s method has been perfected, but Dagognet’s final sentences (which are somewhat reminiscent of the logic with which Foucault ends his Order of Things [1966]) suggest that it is about to disappear, overcome by the multiplication of its terms. ‘Another symbolic system, for which we’ve been searching for a long time, will replace it. It will fully realise and accomplish the function of representation’ (CpA 9.13:194).

References to this text in other articles in the Cahiers pour l’Analyse:


English Translation:


Primary bibliography

  • Lavoisier, Antoine, and Louis-Bernard Guyton de Morveau, Antoine-François de Fourcroy, Claude-Louis Berthollet, Méthode de nomenclature chimique. Paris: Chez Chuchet, 1787.
  • Lavoisier, Antoine, Traité élémentaire de chimie, présenté dans un ordre nouveau et d’après les découvertes modernes. Paris: Chez Cuchet, 1789 (reprinted in 1965, by Cultures et Civilisations). The text is available online as part of Les Oeuvres de Lavoisier: Une édition électronique des Œuvres d’Antoine Laurent Lavoisier, published by the CNRS, It was translated into English by Robert Kerr in 1790 as Elements of Chemistry (republished by Dover, in 1965). A pdf scan of the 1802 edition of Kerr’s translation is available at Internet Archive,
  • Dagognet, François, Philosophie biologique. Paris: PUF, 1955.
  • ---. La Raison et les remèdes, essai sur l’imaginaire et le réel dans la thérapeutique contemporaine. Paris: PUF, 1964
  • ---. Gaston Bachelard: sa vie, son oeuvre, avec un exposé de sa philosophie. Paris: PUF, 1965.
  • ---. Tableaux et langages de la chimie. Paris: Éditions du Seuil, 1969.
  • ---. Pour une théorie générale des formes. Paris: Vrin, 1975.

Selected secondary works

  • Beaune, Jean-Claude et al. eds., François Dagognet, médecin et philosophe. Paris: L’Harmattan, 2006.
  • Bensaude-Vincent, Bernadette, ‘Chemistry in the French Tradition of Philosophy of Science: Duhem, Meyerson, Metzger and Bachelard.’, Studies in History and Philosophy of Science Part A, 36:4 (December 2005): 627-649.
  • Canguilhem, Georges, et al.eds., Anatomie d’un épistémologue: François Dagognet. Paris: Vrin, 1984.
  • Damien, Robert, ed., François Dagognet, médecin, épistémologue, philosophe: une philosophie à l’œuvre. Le Plessis-Robinson: Institut Synthélabo, 1997.
  • Guery, François, ‘François Dagognet ou le paradoxe empirico-transcendantal’. Archives de Philosophie (Paris) 44:33 (1981): 371-381.
  • Holmes, Frederic Lawrence, Lavoisier and the Chemistry of Life. Madison, Wisconsin: University of Wisconsin Press, 1985.
  • Poirier, Jean-Pierre, Lavoisier: Chemist, Economist, Biologist. Philadelphia: University of Pennsylvania Press, 1996.
  • Smartt Bell, Madison, Lavoisier in the Year One: The Birth of a New Science in an Age of Revolution. NY: Atlas Books/Norton, 2005.