2.6.2 Newton's Legacy

Or What He Did and Did Not Do

To understand how Newton’s theories were distorted by his later misinterpreters, consider his laws of motion, in his own words (from a 1729 translation of the Latin original) [[i]]:

1. Every body perseveres in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impress’d thereon.

2. The alteration of motion is ever proportional to the motive force impress’d; and is made in the direction of the right line in which that force is impress’d.

3. To every action there is always opposed an equal reaction; or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.

Figure 2.34 shows the original 1729 pages in context.

Figure 2.34: Newton’s Laws of Motion (1729) [[ii]].

Even many physics textbooks show only a vague and passing familiarity with Newton’s accomplishments. Students of physics may be excused if they leave class with the impression that the whole body of classical physics sprung complete and perfected from Newton’s Olympian genius. Let’s digress a moment to examine how long it took Newton’s ideas to take hold, and exactly what he did and did not accomplish.

With the benefit of hindsight, we can acknowledge Newton’s greatness. At the time, however, Cartesian plenums were slow to yield to Newtonian forces of attraction across a vacuum. Writing in 1730, three years after Newton’s death, Voltaire (1694–1778), the foremost advocate of all things British within France [[iii]], proclaimed, “A Frenchman who arrives in London will find Philosophy, like everything else, very much changed there. He had left the world a plenum, and now he finds it a vacuum…. In France, ’tis the Pressure of the Moon that causes the Tides; but in England, ’tis the Sea that gravitates toward the Moon… ” [[iv]].

Using Newton’s methods, in 1705, Edmond Halley (1656–1742) noted that a 1682 comet had nearly the same orbital characteristics as comets seen in 1607 and 1531. He predicted the comet’s return in 1758, but did not live to see what we now call “Halley’s Comet” when it arrived in December of that year. “No one ever seriously questioned Newton’s theory after the return of Halley’s comet,” opined British geneticist and evolutionary biologist, J.B.S. Haldane (1892–1964) [[v]].

Figure 2.35: François-Marie Arouet (1694–1778), known as Voltaire, [[vi]] left, and Edmond Halley (1656–1742), right [[vii]].

The implications of Newtonian physics took time to become clear. The modern form of Newton’s Laws of Motion was not developed until more than a generation after the 1687 publication of the Principia. For instance, the first to derive what we would now recognize as a partial differential equation as a law of motion was Jean le Rond d’Alembert (1717–1783). The first general formulation of what are now called the Newtonian Equations of Motion (including force equals mass times acceleration or “F = ma”) was provided by Leonhard Euler (1707–1783) in 1752 [[x]]. Newton laid the foundation, but a host of talented successors contributed to what became known as Newtonian mechanics [[xi]].

Figure 2.36: Jean le Rond d’Alembert (1717–1783) [[viii]], left and Leonhard Euler (1707–1783) [[ix]], right.

In any event, the physical laws discovered by Newton were not the result of some serendipitous accident, but rather the logical consequence of a proper scientific method. In fact, Newton’s work remains an archetype against which all other scientific investigations may be compared. As philosopher John Herman Randall, Jr. (1899–1980) poetically observed, “His [Newton’s] intellectual method was the voice of science itself” [[xii]].

Next time, we will explore how Newton’s work and approach were distorted by his successors.

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References

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[i] Newton, Isaac, Mathematical Principles of Natural Philosophy, Andrew Motte, trans., 1729 pp. 19-20. See: https://books.google.com/books?id=Tm0FAAAAQAAJ&newbks=1&newbks_redir=0&dq=newton%20principia&pg=PA18#v=twopage&q&f=false

[ii] Newton, Isaac, Mathematical Principles of Natural Philosophy, (3^rd ed., Andrew Motte, trans., with notes by Florian Cajori), Berkeley, CA: University of California Press, 1962, Book III Proposition XLI, Problem XXI, pp. 519. Originally published, 1726. See: https://commons.wikimedia.org/wiki/File:Newton_Comet1680.jpg

[iii] Jones, E. Michael, Barren Metal: a history of capitalism as the conflict between labor and usury, South Bend, Indiana: 2014, p. 617-8. Voltaire went from prisoner in the Bastille to being fêted by the English aristocracy with a speed that some observers, including Alexander Pope, suspected was prompted not by his literary merit, but rather because he was a paid spy and propagandist. Voltaire became the ”apostle of English ideas” to France, promoting tolerance, capitalism, Freemasonry, and Newtonian physics.

[iv] Voltaire, Francois-Marie Arouet, Letters on England, Letter XIV On Descartes and Sir Isaac Newton, 1730. See: http://www.online-literature.com/voltaire/letters_england/14/

[v] Haldane, J.B.S., “Daedalus or Science and the Future,” A Paper Read to the Heretics, Cambridge, on February 4^th 1923. See: http://bactra.org/Daedalus.html

[vi] See: https://infogalactic.com/info/File:Nicolas_de_Largilli%C3%A8re,_Fran%C3%A7ois-Marie_Arouet_dit_Voltaire_(vers_1724-1725)_-001.jpg

[vii] By Richard Phillips - National Portrait Gallery: NPG 4393, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16134634

[viii] Maurice Quentin de La Tour/ Jean Le Rond d'Alembert https://www.wikiart.org/en/maurice-quentin-de-la-tour/jean-le-rond-d-alembert

[ix] https://infogalactic.com/info/File:Leonhard_Euler.jpg

[x]  Clifford Truesdell, Essays in the History of Mechanics, (New York:  Springer-Verlag, 1968) pp. 111-114.

[xi]  Clifford Truesdell, Op.Cit., Chapters II & III.  Truesdell has a particularly lucid and detailed analysis of Newton and his successors, from which much of my information on the subject was drawn.

[xii]  John Herman Randall, Jr., “What Isaac Newton Started” [Introduction to Newton's Philosophy of Nature:  Selections From His Writings (H.S. Thayer, ed.)], (New York:  Hafner Press, 1953), p. xiv.