Pierre Louis Moreau de Maupertuis

Pierre Louis Moreau de Maupertuis (born the July 7th 1698 with Saint-Malo - died with Basle the July 27th 1759) is a Mathématicien and Astronome French.

Its life

Principle of less action

It stated the Principe of less action. One owes him, after Lucrèce, to have had the intuition of this principle. More than one century and half before the quantum revolution, it opens the conceptual way of the integral of the ways of Feynman and the electrodynamics Quantique.

Origin and course

He is the son of a Corsaire inhabitant of Saint Malo anobli by Louis XIV, trading. At the twenty years age his/her father, with whom it has a very close relation, offers to him a regiment of cavalry (gray musketeers) of which he is lieutenant but he prefers to study mathematics and becomes member of the Academy of Science in 1723. He publishes various work of mechanics and Astronomie but also of the “observations and experiments” on animals still badly known at the time, like the salamander S and the scorpion S, which shows already its talents of Biologiste.

London

In 1728 it visits London and is elected member of the Royal Society. This voyage marks a decisive turn in its career. It discovers there the ideas of Newton, in particular the Gravitation, of which it will become a burning propagandist in France. It has some merit to do it because, at the time, it is the Cartesian theory of the “swirls” which holds place of official doctrines to explain the operation of the Univers. This design of Descartes stipulated that the movements of planets were due to their drive by “swirls of a subtle matter occupying interstellar spaces”. By theoretical considerations, Newton had found that the ground was to have the shape of an ellipsoid of revolution, flattened with the poles, contrary with Jacques Cassini which affirmed that it was lengthened with the poles. This controversy between Newtonian and cassiniens occupied most of the scientific essays of the end of XVII E and of the beginning of the 18th century. Only direct measurements could slice the debate.

The pole arc

Two forwardings were thus organized by the Academy of Science of Paris to regulate this problem. The purpose of this great geodetic forwarding was to measure the length of a pole arc and an equatorial arc to determine the form of the Ground. A scientific controversy is established then, in particular between Jacques Cassini and Maupertuis. The first, is that of Lapland, which lasted of 1736 with 1737. Directed by Maupertuis, it confirmed the theory of Newton. It was the same for the second forwarding led to the Peru by Godin, Bouguer and Condamine. As 1736 it thus acts as chief of the forwarding sent by Louis XV in Lapland to measure the length of a degree of the Méridien, and on its return he became member of almost all the scientific companies of Europe. The doubt will be raised in 1756. Cassini was wrong, Maupertuis was right. The results of measurements confirm the sights of Newton fully and make it possible to describe the true “shape of the Earth”. It is haloed of glory and Voltaire pays homage to him:

Héros of physics, Argonautes new

Who cross the mounts, which cross water

Whose immense work and exact measurement

Of the astonished ground fixed the figure .

Reveal these springs, which make gravity.

You know the laws which its author establishes.

like D' Alembert, which in the preliminary speech with the Encyclopedia, written:

the first which dared among us to be declared Newtonian openly, is the author of the Discours on the figure of the stars . Maupertuis believed that one could be good citizen without blindly adopting the physics of his country, and to tackle this physics, it needed a courage which one must know liking to him.

It has a relation close with Emilie to Châtelet.

Berlin

In 1740 Maupertuis goes to Berlin to the invitation of Frederic II of Prussia and takes share with the Bataille of Mollwitz where it is made prisoner by the Autrichiens. To its release it goes back to Berlin then to Paris where it is allowed with the French Academy. Maupertuis becomes the target of the philosophical and its old friend Voltaire. Indeed, one of its more virulent enemies of this period is not other than Voltaire, from now on jealous of his friendship with Frederic II. The king takes the defense of Maupertuis and it is Voltaire who must leave Berlin, disgraced, while one burns on the most sarcastic public place his Libelle S as the pitiless caricature Micromégas .

Epilog

After being remained some time in the south of France to look after its declining health there dies in Basle. Its ombrageux character made it quarrel, in particular with Samuel König.

Like many scientists of the time, Maupertuis is not confined with a narrow discipline but is illustrated in turn as a Mathématicien, Astronome, Géographe, Naturaliste. He is also worried Philosophie. He makes proposals to improve the organization of the Médecine and other sciences applied.

Its work

Work in genetics

In physical Venus , Maupertuis is opposed in 1745 then to the Théorie of preformation of the Embryon in vogue, by affirming that the father and the mother have an equal influence on the Hérédité. It tries to explain the genetic phenomena by a physicochemical theory of attraction. Volume contains two essays, one on the origin of the men and the animals, the other on the origin of the blacks. The Physical Dissertation at the time of the White Negro had separately been published the previous year and also contains important contributions to the theory Génétique. The following points emerge: the white color of the negro is a hereditary anomaly. Maupertuis insists on a fact that we call, today, Mutation 488. The abbot Pichon will make appear in 1765 a refutation of the assumption of Maupertuis. Jean Rostand, in a work published at Gallimard, in 1966, Men of yesterday and today , qualifies Maupertuis of astonishing precursor of the genetics. Ten years front, Bentley Knell, of the university of Baltimore, published a work initulé Maupertuis, has forgotten genius . The obviousness was that Maupertuis is in advance over its time.

Work in biology

Maupertuis was mathematician and fine expert of the theories of Newton and Leibniz, but it had understood that the physical theories of Newton were insufficient to explain the biological phenomena. In this direction, it was one of the thinkers more in advance over their time, because it was opposed to the Préformisme, the Newtonian Déterminisme and even to the Créationnisme. It is following the exposure of a Black Albinos that it is interested in what will be one of its subjects of predilection: the Heredity and especially the hereditary changes. Indeed, on this level it was one of the precursors of the modern Génétique.

For him, nature too much much was diversified and heterogeneous so that the world was created by intention. It is not known if it were atheistic deist or . No matter what it was, its materialist attitude, due to his knowledge of the Newtonian theories, and its interest for heredity enabled him to curiously develop a theory of the life being connected with the Mutationnisme of Hugo de Vries. He considered that the first forms of life had appeared by spontaneous Generation starting from inert matter combinations randomly, Molécule S or Germe S - thus carrying out a return to the ancient authors such as Lucrèce. Indeed, the invention of the Microscope led to the observation of organizations tiny and unknown reducing the distance between living organism and inanimate nature, which randomly gave a powerful support for the assumption of the spontaneous Generation starting from inert matter combinations.

A long time it was believed that the microscopic organizations, in particular the Infusoire S, could be generated starting from inorganic matter. Thus from first forms of life appeared by generation spontaneous, Maupertuis considered that a series of fortuitous changes - because with each time a newborn was different from his/her mother and of his/her father that caused the appearance of a new species - repeated during time could generate an always increasing multiplication of species thus explaining, according to him, the great diversity of all the species of the Earth. It went even until formulating the elimination of the defective mutants. However, Maupertuis was essentialist, i.e. it posed a priori each species as being definitely distinct from his neighbors in the plan taxinomic and even if it could conceive the production of new gasolines, it was unable to imagine a continuous and gradual evolution populations by the selection of the individuals best adapted.

Its publications

Its most important work:

the Figure of the Earth, determined by the Observations of Sirs Maupertuis, Clairaut, Camus, Monnier & of Mr. the Outhier Abbot, accompanied by Mr. Celsius . (Paris, 1738)
Speech on the parallax of the Moon, to improve the Theory of the Moon and that of the Earth. (Paris, 1741).
Speech on the figure of the stars (Paris, 1732)
Elements of the geography (Paris, 1742). Method and results showing sphericity and flatness of the sphere to the poles, joining the theories of Newton.
Letter on comet of 1742 (Paris, 1742)
nautical Astronomy or élémens of Astronomy, both for a fixed observatory, a mobile observatory. (Paris, 1743,1745 and 1746)
physical Venus (Paris, 1745).
Test of Moral Philosophy . Berlin, 1749. Leyde, Luzac, 1751. It is, with that entitled " Test of Cosmologie" , the principal philosophical text of Maupertuis.
Test of cosmology (Amsterdam, 1750, Imp. Luzac Leyde, 1751).

Dissertatio inauguralis metaphysica, of universali naturae systemate, pro gradu doctoris lived (Erlangen, 1751) Under the false name of Doctor Baumann.
Test on the formation of organized bodies (Paris, 1954, but printed in Berlin). Translation of the " Dissertatio"

Its works were published in 1752 with Dresden and 1756 with Lyon.

various Works… Elemens de Géographie. Speech on the various figures of the Celestial bodies. Speech on the Parallax of the Moon and Letter on the Comet , Amsterdam, 1744.

Some texts in line

Voyage in Lapland
Voyage to the Polar circle
On the language

Secondary bibliography

Elisabeth Badinter, intellectual Passions - Desires of glory (1735-1751), Beech, 1999. This book is interested in environment of the Parisian living rooms at the XVIIIème century, where Maupertuis shone.

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