Physiology and the whole organism · Article

Central forces and the impossibility of perpetual motion

The impossibility of perpetual motion is the claim that a system cannot deliver work without a matching supply. Helmholtz stated a conservation principle about the work done by the mutual forces of bodies.¹ Later writers in physiology and biology used it as a test. Bayliss used it to limit what a membrane could be asked to do.⁷

Earliest held: 1847, Helmholtz, H.
Most discussed in: Über die Erhaltung der Kraft, 1847
In the library: 18 passages in 10 works
Rewritten: 2026-10-27

Helmholtz and central forces

Helmholtz (1847) described bodies that gain velocity under their mutual forces. That velocity can be counted as mechanical work.¹ To obtain the same work a second time, the bodies must be returned to their starting conditions by other forces, and that costs work.¹ His principle required that the work gained and lost between two positions be the same, whatever the manner of passage. James (1890) later noted that the hypothesis of molecules and central forces was the one from which constancy, or conservation, was logically deduced.² Driesch (1908) described the mechanical view of nature as an arrangement of mass-elements possessing central forces.⁵

A problem that dissolved

Verworn (1899) placed perpetual motion among problems that disappeared without a solution. Verworn noted that no one had built such a machine, and said these problems vanish once their basis is seen to be false.³ Henderson (1913) put the result in thermodynamic terms. Energy flows in one direction, perpetual motion is impossible, and useful energy is steadily degraded.⁶ Lotka (1925) drew a parallel. Lotka wrote that inventors who abandoned the machine were rewarded with the law of conservation of energy. Lotka proposed resigning from the attempt to define life, at least as a temporary expedient, together with Schäfer. Lotka added only that, perhaps, this followed historical precedent.⁹

Use in physiology

Bayliss (1915) used the impossibility as an argument about membranes. Bayliss doubted an irreciprocal permeability. Morgan (1901) used a different phrase in a different sense. Excretion of urea stayed the same after one kidney was removed, so Morgan concluded that under normal conditions the kidneys do not perform their maximum of work.⁴

Where the analogy fails

Loeb (1916) rejected the comparison between making living matter artificially and building a perpetuum mobile. Loeb argued that a perpetuum mobile contradicts the first law of thermodynamics. Making living matter might be impossible, Loeb said, without contradicting any natural law.⁸ Loeb's view contrasts with Lotka's broader parallel. Lotka treated abandoned goals in several sciences as alike in kind.⁹ Loeb kept the conservation of energy for a strict case and left the origin of life as an open question.⁸

SourcesEach quotation was checked word for word against the passage it opens.

so milssen wir die Korper auf irgend eine Yf eise in die anfangiiclieu Be- dingmigen diirch Anwendimg anderer nns zii Gebote stehender Krafte zurtlckversetzenHelmholtz, H., 1847 · Über die Erhaltung der Kraft · open at passage 11
stancy or * conservation ' gives the name to the hypothesis of molecules and central forces from which it was logically deduced.James, W., 1890 · The Principles of Psychology, Vols. 1-2 · open at passage 3230
that of perpetual motion, which since early times has been prominent in physics, and many others, have quite disappeared, although no one has ever squared the circle and no one has constructed a machine for perpetual motion.Verworn, M., 1899 · General Physiology: An Outline of the Science of Life · open at passage 123
This means that, under normal conditions, the kidneys do not perform their maximum of work.Morgan, T. H., 1901 · Regeneration · open at passage 303
But whenever nature is regarded as a mechanical system of the dynamical type, it is conceived as a typical arrangement of mass-elements possessing central forcesDriesch, H., 1908 · The Science and Philosophy of the Organism · open at passage 436
On the whole, energy can flow in but one direction; perpetual motion is impossible; and useful energy is steadily becoming de- graded, dissipated, and useless.Henderson, L. J., 1913 · The Fitness of the Environment · open at passage 33
Otherwise, there would be a spontaneous difference of potential kept up between the two sides of the membrane and the possibility of a perpetual motion machine.Bayliss, W. M., 1915 · Principles of General Physiology · open at passage 638
The idea of a perpetuum mobile contradicts the first law of thermodynamics, while the making of living matter may be impossible though contradicting no natural law.Loeb, J., 1916 · The Organism as a Whole, from a Physicochemical Viewpoint · open at passage 72
Enlightened inventors have abandoned the attempt to build a perpetual motion machine; but again, resignation is rewarded with the recognition of a fundamental law, the law of conservation of energy.Lotka, A. J., 1925 · Elements of Physical Biology · open at passage 111

Linked ideas

Resting membrane potentialrelated to

Bayliss argued that a lasting potential difference across a membrane needs an energy supply from the cell, or it would be a perpetual motion machine.

Vitalism and mechanismrelated to

Driesch described the mechanical view as central forces among mass-elements. Loeb separated the origin of life from the first law of thermodynamics.

Fitness of the environmentrelated to

Henderson stated that energy flows one way and that perpetual motion is impossible, as part of his account of thermodynamics.

Homeostasis and the internal environmentrelated to

Morgan's remark that kidneys do not perform their maximum of work concerns capacity held in reserve, as in the regulation of an organ.

Light as the source of living energyrelated to

Both concern the supply of energy to living systems and the limits conservation places on what they can do.

Metabolism and cell faterelated to

Energy supplied by cell activity is what, in Bayliss's argument, keeps a living membrane from being a perpetual motion machine.

Conservation of energy (Erhaltung der Kraft)related to

The same principle seen from the negative side: no process yields energy from nothing.

Conservation of energy and the mechanical equivalent of heatrelated to

The same principle seen from the other side: a machine cannot yield more energy than it receives.

Where it is discussedPassages matching perpetual motion, perpetuum mobile, maximum of work, Arbeitsgrösse

1847	Über die Erhaltung der Kraft · Helmholtz, H.	5
1901	Regeneration · Morgan, T. H.	2
1925	Elements of Physical Biology · Lotka, A. J.	2
1890	The Principles of Psychology, Vols. 1-2 · James, W.	2
1915	Principles of General Physiology · Bayliss, W. M.	2
1899	General Physiology: An Outline of the Science of Life · Verworn, M.	1
1916	The Organism as a Whole, from a Physicochemical Viewpoint · Loeb, J.	1
1913	The Fitness of the Environment · Henderson, L. J.	1
1908	The Science and Philosophy of the Organism · Driesch, H.	1
1957	An Introduction to the Study of Experimental Medicine · Bernard, C.	1