Pierre Louis Maupertuis — The Shape of the Earth, the Principle of Least Action, and the Eccentric Genius (1698–1759)

Pierre Louis Moreau de Maupertuis was a French mathematician, philosopher of science, and naturalist whose wide-ranging intellectual career took him from the flattened poles of the earth to the foundations of physics, from the courts of Frederick the Great to the speculative borders of biology and cosmology.

A man of brilliant originality and difficult temperament — celebrated and satirized in equal measure, the subject of one of Voltaire's most savage attacks and one of Frederick the Great's most loyal friendships — he made contributions to mechanics, cosmology, and biology that anticipated ideas developed fully only centuries later.

His central concern: that nature operates according to principles of economy and elegance — that the universe is organized not by brute force but by optimization, and that discerning these principles was the highest task available to the scientific mind.

Flattening the Earth — The Lapland Expedition

In 1736 Maupertuis led one of the most ambitious scientific expeditions of the eighteenth century — a journey to Lapland near the Arctic Circle to measure the length of a degree of latitude and determine whether the earth was flattened at the poles as Newton had predicted, or elongated at the poles as the Cassinis had argued from French measurements.

The expedition endured extreme cold, equipment failures, difficult terrain, and the considerable challenge of conducting precision geodetic measurements in the conditions of the far north. When Maupertuis returned to Paris with his results — confirming Newton's prediction that the earth was an oblate spheroid, flattened at the poles and bulging at the equator — he was celebrated as the man who had flattened the earth and confirmed the Newtonian system against its French critics.

Voltaire, who was briefly his friend before becoming his enemy, celebrated him as "the flattener of the earth and of Cassinis" — a compliment that captured both the scientific achievement and the satisfying defeat of an influential rival school. The title would later be turned against him when Voltaire's satire "Micromégas" and then the more savage "Diatribe of Doctor Akakia" made Maupertuis a figure of mockery across the courts of Europe.

"The shape of the earth is determined by experiment — and experiment has spoken for Newton."

The Principle of Least Action — Nature's Economy

Maupertuis's most enduring and most philosophically significant contribution was his formulation of the principle of least action — the proposition that in any physical process, nature always follows the path that minimizes a quantity he called "action," which combined mass, velocity, and distance.

He announced the principle in 1744, arguing that it expressed a fundamental truth about the universe: that nature is economical, that it does not waste effort, that every physical process proceeds by the path of least expenditure consistent with the constraints imposed. This was not merely a mathematical convenience — it was, for Maupertuis, a proof of divine wisdom. A God who created a universe governed by such elegant economy was more worthy of worship than one who created chaos.

The principle was developed into a rigorous mathematical framework by Euler and Lagrange and became one of the foundations of analytical mechanics — and ultimately of quantum mechanics and field theory, where the action principle in its modern form underlies the path integral formulation and the standard model of particle physics. Maupertuis had glimpsed something real and fundamental about the structure of physical law that it took two centuries to fully develop.

"Nature is thrifty in all its actions — wherever light is refracted or reflected, it always takes the path that requires the least action."

Biology and the Seeds of Evolutionary Thought

Less well known than his work in physics but philosophically more daring was Maupertuis's engagement with biological questions — particularly with heredity, variation, and the origin of species.

In his "Vénus physique" (1745) and "Système de la nature" (1751), he proposed ideas that anticipate natural selection by more than a century. He argued that organic matter possessed elementary particles with some form of memory or preference — what we might call biological information — and that the variety of living forms arose from chance combinations and modifications of these particles that were then transmitted to offspring.

He recognized that successful variations would tend to persist while unsuccessful ones would be eliminated — a rough formulation of what Darwin would make precise. He also studied polydactyly in a Berlin family across several generations, producing what is sometimes cited as the first statistical analysis of Mendelian inheritance — a century before Mendel.

He was speculating in advance of the evidence — making intuitive leaps that the science of his time could neither confirm nor refute. But the leaps were in the right direction, which is itself a form of genius.

"Could we not explain in this way how from just two individuals the multiplication of the most dissimilar species could have followed?"

Frederick the Great and the Berlin Academy

In 1745 Frederick the Great invited Maupertuis to Berlin as President of the newly reorganized Berlin Academy of Sciences — a position that gave him both prestige and enemies in roughly equal measure.

He was a demanding and sometimes tyrannical administrator — his conflicts with the mathematician Samuel König over the priority of the least action principle became a scandal that divided European learned society. Maupertuis accused König of forging a letter from Leibniz that purported to show Leibniz had anticipated the principle. The Academy sided with Maupertuis. Voltaire sided with König — or rather, used the dispute as the occasion for the "Diatribe of Doctor Akakia," a vicious satirical pamphlet that destroyed Maupertuis's reputation throughout Europe and ended the friendship between Voltaire and Frederick.

Maupertuis never recovered from the mockery — his health declined, he left Berlin, and he died in Basel in 1759, a broken man by most accounts, his genuine achievements overshadowed by one of the most effective character assassinations in the history of the republic of letters.

"I have made enemies of the mathematicians by speaking too much as a philosopher, and of the philosophers by speaking too much as a mathematician."

Cosmological Speculation and the Plurality of Worlds

Maupertuis was among the eighteenth century thinkers who took seriously the possibility of life elsewhere in the universe — arguing from the principle of plenitude that a universe governed by economy and reason would not waste the vast spaces between the stars.

His cosmological speculations extended to questions about the origin of the universe itself — whether chance alone could explain the emergence of order, or whether some organizing principle was required. His answer was characteristically hybrid: chance operating on particles endowed with elementary properties could produce complex organization, but the source of those elementary properties remained a question for theology rather than physics.

He was a deist rather than an orthodox Catholic — finding in the principle of least action evidence of divine rationality without feeling the need to defend particular doctrines. The God revealed by physics was an elegant mathematician, not the God of revelation — and Maupertuis was content with the mathematician.

"The principle of least action is perhaps the first glimpse that science has afforded us of the economy of nature — and economy implies a mind that calculates."

Legacy — The Pioneer Who Was Mocked into Obscurity

Maupertuis's reputation has never fully recovered from Voltaire's attack — the Akakia pamphlet was too funny, too widely circulated, too perfectly aimed at his genuine personal vulnerabilities to be overcome by subsequent rehabilitation. He is remembered, when he is remembered at all, as a footnote to the careers of Euler, Lagrange, and Darwin — the man who glimpsed what others would develop.

This is a significant injustice. The principle of least action is one of the deepest ideas in physics — a principle whose full implications are still being worked out in quantum field theory and string theory. The biological speculations anticipate Darwin, Mendel, and genetics with a boldness that deserves recognition in its own right. The Lapland expedition was a genuine scientific achievement that required both intellectual courage and physical endurance.

He stands on CivSim alongside Weyl and Clifford — thinkers who reached further than their tools allowed, whose intuitions pointed in directions that took subsequent generations to follow, and whose contributions were obscured by personal controversies that had nothing to do with the quality of their thought. The history of science is full of such figures — pioneers who were in the right place but not quite at the right time, or who were in the right time but made the wrong enemies. Maupertuis was both.

"In vain do we seek a simpler and more universal law of nature — the principle of least action extends to optics, to mechanics, to all of physics, and perhaps beyond."