Hamilton's principle/History/The Maupertuis-Koenig affair - Revision history

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			{{DISPLAYTITLE:The Maupertuis-Koenig affair}}
	In 1751 Samuel Koenig claimed that the principle of least action was not		In 1751 Samuel Koenig claimed that the principle of least action was not
	Maupertuis's, and that Leibniz had stated it in a letter of 1707. The dispute that		Maupertuis's, and that Leibniz had stated it in a letter of 1707. The dispute that
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	the priority question is UNCOMPUTED. See [[Hamilton's principle/Sources]].		the priority question is UNCOMPUTED. See [[Hamilton's principle/Sources]].
	</blockquote>		</blockquote>

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In 1751 Samuel Koenig claimed that the principle of least action was not
Maupertuis's, and that Leibniz had stated it in a letter of 1707. The dispute that
followed ran for years, drew in Euler, Voltaire and Frederick the Great, and
ended a reputation.

This page sets out the dispute. '''It does not deliver a verdict''', and the
reason is given at the end.

== The claim ==

Koenig, a mathematician and a member of the Berlin Academy over which Maupertuis
presided, published a paper questioning the principle. Two claims were bundled
together in it, and separating them matters.

The '''first''' was mathematical: that the principle as Maupertuis stated it was
wrong.

The '''second''' was historical: that in so far as it was right, it was Leibniz's,
stated in a letter written in 1707.

Koenig quoted the letter. He did not produce it. He had a copy, and said the
original was elsewhere.

== The response ==

The Berlin Academy, with Maupertuis presiding and Euler taking the lead, declared
the letter a forgery.

Euler wrote a paper on the affair. He defended Maupertuis's priority, argued the
principle was sound, and treated the Leibniz letter as fabricated.

The proceeding was not a neutral inquiry. The Academy was judging a challenge to
its own president, and the man who wrote its case was that president's colleague
and appointee.

== Voltaire ==

Voltaire, resident at Frederick's court and by then hostile to Maupertuis,
attacked him in print with considerable savagery, and mocked Euler along with him.

Frederick the Great defended Maupertuis and had Voltaire's pamphlet burned.
Voltaire left Prussia.

The literary quarrel is better remembered than the scientific one, which is part
of why the affair is usually told as a comedy. Its effect on Maupertuis was not
comic: his standing did not recover, and he left Berlin some years later in poor
health.

== What has changed since ==

Two things, and both cut against the Academy's finding.

The Leibniz letter is now generally regarded as '''authentic''', on the basis of
manuscript evidence found after the affair. The Academy's forgery verdict is not
sustained.

And Leibniz did have relevant ideas about extremal quantities in nature, though
whether they amount to the principle at issue is a separate question from whether
the letter is genuine.

So the historical part of Koenig's claim looks better now than it did in 1751, and
the Academy's handling of it looks worse.

== Why this page stops here ==

The volume's charter records this reception history as '''uncomputed''', with the
work required stated: read the secondary literature on the affair, and the Euler
correspondence, before asserting a verdict.

That reading has not been done for this volume.

What is above rests on encyclopedia-level summaries and on references encountered
while surveying sources for other pages. That is enough to say what the dispute
was about and that the modern view has shifted. It is '''not''' enough to say how
much of Maupertuis's claim survives modern scholarship, which is the question the
charter actually asks.

So the page states the dispute and stops. The verdict is
'''UNCOMPUTED''', and its kind of block is '''computation''': the material is
reachable, and the reading has not been performed. See
[[Hamilton's principle/Sources]].

This is a deliberate choice rather than an omission. A confident narrative would be
easy to write and would be worth nothing, because it would rest on the same
tertiary summaries every other confident narrative rests on.

== What can be said without the reading ==

Three things are safe, and they are worth stating because they bear on the rest of
the volume.

'''Priority disputes are not settled by academies with an interest.''' Whatever the
truth about the letter, a body chaired by the accused party's beneficiary was not
the right forum, and the finding has not held.

'''Euler's conduct is the part that ages worst.''' He was the best mathematician
involved by a wide margin, he had an independent and better-founded claim of his
own, and he spent his authority defending someone else's priority in a proceeding
he should not have been part of. His mathematics on
[[Hamilton's principle/History/Euler and the Methodus inveniendi]] is untouched by
this. His judgement is not.

'''The dispute was about the wrong thing.''' Both sides argued over who first said
that nature minimises action. Nature does not minimise action. Within a century
Hamilton would correct the word, and within two the quantum account on
[[Hamilton's principle/Applications/The Feynman path integral]] would remove the
idea of nature choosing anything at all.

The priority being fought over was priority in a formulation that turned out to be
wrong in its central word.

== Where to go next ==

The next development is Lagrange's, and it is at
[[Hamilton's principle/History/Lagrange and the Mecanique analytique]].

<blockquote>
Provenance: nothing on this page is quoted from a primary source. Koenig's paper,
Euler's paper on the affair, the Leibniz letter and Voltaire's pamphlets are not
sources of this volume, and no words are attributed to any of them. The verdict on
the priority question is UNCOMPUTED. See [[Hamilton's principle/Sources]].
</blockquote>

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	'''UNCOMPUTED''', and its kind of block is '''computation''': the material is		'''UNCOMPUTED''', and its kind of block is '''computation''': the material is
	reachable, and the reading has not been performed. See		reachable, and the reading has not been performed. See
	[[Hamilton's principle/Sources]].		[[Hamilton's principle/Sources\|Sources]].

	This is a deliberate choice rather than an omission. A confident narrative would be		This is a deliberate choice rather than an omission. A confident narrative would be
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	own, and he spent his authority defending someone else's priority in a proceeding		own, and he spent his authority defending someone else's priority in a proceeding
	he should not have been part of. His mathematics on		he should not have been part of. His mathematics on
	[[Hamilton's principle/History/Euler and the Methodus inveniendi]] is untouched by		[[Hamilton's principle/History/Euler and the Methodus inveniendi\|Euler and the Methodus inveniendi]] is untouched by
	this. His judgement is not.		this. His judgement is not.

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	that nature minimises action. Nature does not minimise action. Within a century		that nature minimises action. Nature does not minimise action. Within a century
	Hamilton would correct the word, and within two the quantum account on		Hamilton would correct the word, and within two the quantum account on
	[[Hamilton's principle/Applications/The Feynman path integral]] would remove the		[[Hamilton's principle/Applications/The Feynman path integral\|the Feynman path integral]] would remove the
	idea of nature choosing anything at all.		idea of nature choosing anything at all.

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	The next development is Lagrange's, and it is at		The next development is Lagrange's, and it is at
	[[Hamilton's principle/History/Lagrange and the Mecanique analytique]].		[[Hamilton's principle/History/Lagrange and the Mecanique analytique\|Lagrange and the Mecanique analytique]].

	<blockquote>		<blockquote>
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	Euler's paper on the affair, the Leibniz letter and Voltaire's pamphlets are not		Euler's paper on the affair, the Leibniz letter and Voltaire's pamphlets are not
	sources of this volume, and no words are attributed to any of them. The verdict on		sources of this volume, and no words are attributed to any of them. The verdict on
	the priority question is UNCOMPUTED. See [[Hamilton's principle/Sources]].		the priority question is UNCOMPUTED. See [[Hamilton's principle/Sources\|Sources]].
	</blockquote>		</blockquote>