Pierre Duhem · Lablypedia

Early life and education

Pierre Duhem was born in Paris on 10 June 1861. He was the son of Pierre-Joseph Duhem, who was of Flemish origins, and Marie Alexandrine née Fabre, whose family hailed from Languedoc. Pierre-Joseph worked as a sales representative in the textile industry and the family lived in a modest neighborhood on the Rue des Jeûneurs, just south of Monmartre. The family was devoutly Catholic and its conservative outlook was influenced by having lived through the Paris Commune of 1871, which the Duhems saw as a manifestation of the anarchy that must follow from the rejection of religion.

The young Pierre completed his secondary studies at the Collège Stanislas, where his interest in the physical sciences was encouraged by his teacher Jules Moutier, who was a theoretical physicist and the author of influential textbooks on thermodynamics. Pierre was admitted as the first-ranked of his cohort at the prestigious École normale supérieure (ENS) in 1882. At the ENS, he completed licentiates in mathematics and physics in 1884. He then earned his agrégation in physical sciences in 1885.

Duhem prepared a doctoral thesis on the use of the thermodynamic potential in the theory of electrochemical cells. In his thesis, Duhem explicitly attacked the "principle of maximum work" as framed by Marcellin Berthelot. The jury rejected that thesis and Duhem's academic career appears to have been hampered ever after by his differences with Barthelot. In addition to their scientific disagreements, Duhem was a conservative Catholic and royalist, whereas the politically powerful Barthelot was an anti-clerical republican. In 1888 Duhem finally received his doctorate with a new thesis on the theory of magnetization dynamics.

Despite his accomplishments as a theoretical physicist, and later as a historian and philosopher of science, Duhem never obtained the academic position in Paris that he sought. He found work first at the University of Lille (1887–1893), then briefly at the University of Rennes (1893–1894), and finally as a professor of theoretical physics at the University of Bordeaux, where he was based for the rest of his career.

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Theoretical physics

Among scientists, Duhem is best known today for his work on chemical thermodynamics, and in particular for the Gibbs–Duhem and Duhem–Margules equations. His approach was strongly influenced by the early works of Josiah Willard Gibbs, which Duhem effectively explained and promoted among French scientists. In continuum mechanics, he is also remembered for his contribution to what is now called the Clausius–Duhem inequality.

Duhem was a supporter of energetics and was convinced that all physical phenomena, including mechanics, electromagnetism, and chemistry, could be derived from the principles of thermodynamics. Influenced by William Rankine's "Outlines of the Science of Energetics", Duhem carried out this intellectual project in his Traité de l'Énergétique (1911), but was ultimately unable to reduce electromagnetic phenomena to thermodynamic first principles.

Duhem shared Ernst Mach's skepticism about the physical reality and usefulness of the concept of atoms. He therefore did not follow the statistical mechanics of James Clerk Maxwell, Ludwig Boltzmann, and Gibbs, who explained the laws of thermodynamics in terms of the statistical properties of mechanical systems composed of many atoms.

Duhem was an opponent of Albert Einstein's theory of relativity. In 1914, Duhem commented that Einstein's relativity theory "has turned physics into a real chaos where logic loses its way and common-sense runs away frightened". In his 1915 book La Science Allemande, he argued strongly against relativity. Duhem stated that the theory of relativity "overthrow[s] all the doctrines in which one has spoken of space, of time, of movement, all the theories of mechanics and of physics".

History of science

Duhem is well known for his work on the history of science, which resulted in the ten volume Le système du monde: histoire des doctrines cosmologiques de Platon à Copernic (The System of World: A History of Cosmological Doctrines from Plato to Copernicus). As a traditionalist Catholic, Duhem rejected the Enlightened conception of the European Middle Ages as intellectually barren. Instead, he endeavored to show that the Medieval Church had helped to foster the growth of Western science. Duhem's work as a historian of medieval science began with his research on the origins of statics, in the course of which he encountered the works of medieval mathematicians and philosophers such as John Buridan, Nicole Oresme, and Roger Bacon. Duhem came to see in them the true founders of modern science, who in his view had anticipated many of the discoveries of Galileo Galilei and later early modern scientists. Duhem claimed that "the mechanics and physics of which modern times are justifiably proud" had proceeded, "by an uninterrupted series of scarcely perceptible improvements, from doctrines professed in the heart of the medieval schools."

Duhem helped to reintroduce the concept of "saving the phenomena" into the modern philosophy of science. In addition to the debates of the Copernican Revolution on "saving the phenomena" (σῴζειν τὰ φαινόμενα, sozein ta phainomena, contrasted with providing a physical explanation) Duhem was motivated by the thinking of Thomas Aquinas, who wrote concerning the epicycles and eccentrics of classical astronomy that

Reason may be employed in two ways to establish a point: firstly, for the purpose of furnishing sufficient proof of some principle [...] Reason is employed in another way, not as furnishing a sufficient proof of a principle, but as confirming an already established principle, by showing the congruity of its results, as in astronomy the theory of eccentrics and epicycles is considered as established, because thereby the sensible appearances of the heavenly movements can be explained; not, however, as if this proof were sufficient, forasmuch as some other theory might explain them.

Philosophy of science

In the philosophy of science, Duhem is best known for arguing that hypotheses are not straightforwardly refuted by experiment and that there are no crucial experiments in science. Duhem’s formulation of his thesis is that “if the predicted phenomenon is not produced, not only is the questioned proposition put into doubt, but also the whole theoretical scaffolding used by the physicist”. Duhem's views on the philosophy of science are explained in his 1906 work The Aim and Structure of Physical Theory. In this work, he opposed Newton's statement that the Principia's law of universal mutual gravitation was deduced from 'phenomena', including Kepler's second and third laws. Newton's claims in this regard had already been attacked by critical proof-analyses of the German logician Leibniz and then most famously by Immanuel Kant, following Hume's logical critique of induction. But the novelty of Duhem's work was his proposal that Newton's theory of universal mutual gravity flatly contradicted Kepler's Laws of planetary motion because the interplanetary mutual gravitational perturbations caused deviations from Keplerian orbits. Since no contingent proposition can be validly logically deduced from any it contradicts, according to Duhem, Newton must not have logically deduced his law of gravitation directly from Kepler's Laws.

Opposition to the English inductivist tradition

Duhem argues that physics is subject to certain methodological limitations that do not affect other sciences. In his The Aim and Structure of Physical Theory (1906), Duhem critiqued the Baconian notion of "crucial experiments". According to this critique, an experiment in physics is not simply an observation, but rather an interpretation of observations by means of a theoretical framework. Furthermore, no matter how well one constructs one's experiment, it is impossible to subject an isolated single hypothesis to an experimental test. Instead, it is a whole interlocking group of hypotheses, background assumptions, and theories that is tested. This thesis has come to be known as confirmation holism. This inevitable holism, according to Duhem, renders crucial experiments impossible. More generally, Duhem was critical of Newton's description of the method of physics as a straightforward "deduction" from facts and observations.

Duhem's philosophy of science and faith

In the appendix to The Aim and Structure, entitled "Physics of a Believer," Duhem draws out the implications that he sees his philosophy of science as having for those who argue that there is a conflict between physics and religion. He writes, "metaphysical and religious doctrines are judgments touching on objective reality, whereas the principles of physical theory are propositions relative to certain mathematical signs stripped of all objective existence. Since they do not have any common term, these two sorts of judgments can neither contradict nor agree with each other" (p. 285). Nonetheless, Duhem argues that it is important for the theologian or metaphysician to have detailed knowledge of physical theory in order not to make illegitimate use of it in speculations. Duhem's philosophy of science was criticized by one of his contemporaries, Abel Rey, in part because of what Rey perceived as influence on the part of Duhem's Catholic faith. Although Duhem was indeed a believer, a sincere and fervent Catholic, he was eager to point out that his works in physics and chemistry should be considered on their own merits, independent of his religion. They were not examples of "Catholic science," nor even colored by his Catholic faith.

Honors and death

Duhem received an honorary doctorate from the Jagiellonian University, in Kraków, Poland, in 1900. On that same year he was elected as a corresponding member of the French Academy of Sciences. He was promoted to titular non-resident member in 1913. Towards the end of his life, Duhem was recommended as a candidate for the chair of History of Science at the prestigious Collège de France, in Paris. Duhem, however, refused to be considered for the position, explaining in a letter to his daughter that "I am a theoretical physicist. Either I will teach theoretical physics at Paris or else I will not go there." He died suddenly in 1916, at the relatively early age of 55, after suffering from an acute attack of angina while staying in a home that had belonged to his maternal grandfather in the small commune of Cabrespine, near the city of Carcassonne, in the southern department of the Aude.