Пьер Дюгем: Физик, Историк Науки и Философ Термодинамики

French physicist (1861–1916)
the French physician and politician

Pierre Maurice Marie Duhem (pjɛʁ mɔʁis maʁi dy.ɛm, – moʁ ; 9 June 1861 – 14 September 1916) was a French theoretical physicist who worked on thermodynamics, hydrodynamics, and the theory of elasticity. Duhem was also a historian of science, noted for his work on the European Middle Ages, which is regarded as having created the field of the history of medieval science. As a philosopher of science, he is remembered principally for his views on the indeterminacy of experimental criteria (see Duhem–Quine thesis).

Duhem completed a Ph. D. in 1888 at Université Paul Sabatier titled Étude historique sur la théorie de l'aimantation par influence.

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 convinced that all physical phenomena, including mechanics, electromagnetism, and chemistry, could be derived from the principles of thermodynamics. Influenced by Macquorn 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. With Ernst Mach, Duhem shared a skepticism about the reality and usefulness of the concept of atoms. He therefore did not follow the statistical mechanics of Maxwell, 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 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). Unlike many former historians (e. g. Voltaire and Condorcet), who denigrated the Middle Ages, he endeavored to show that the Roman Catholic Church had helped foster Western science in one of its most fruitful periods. His work in this field was originally prompted by his research into the origins of statics, where he encountered the works of medieval mathematicians and philosophers such as John Buridan, Nicole Oresme and Roger Bacon, whose sophistication surprised him. He consequently came to regard them as the founders of modern science, having in his view anticipated many of the discoveries of Galileo Galilei and later thinkers. Duhem concluded that "the mechanics and physics of which modern times are justifiably proud to proceed, by an uninterrupted series of scarcely perceptible improvements, from doctrines professed in the heart of the medieval schools." Duhem popularized the concept of "saving the phenomena." In addition to the Copernican Revolution debate of "saving the phenomena" (Greek σῴζειν τὰ φαινόμενα, sozein ta phainomena) versus offering explanations that inspired Duhem was Thomas Aquinas, who wrote, regarding eccentrics and epicycles, thatReason 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. [ ]

In 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.

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.

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.