Tuesday, September 16, 2014

Thomas Jefferson's secular "trinity" (2): Isaac Newton

"Bacon, Locke and Newton, ... I consider them as the three greatest men that have ever lived, without any exception, and as having laid the foundation of those superstructures which have been raised in the Physical & Moral sciences." - Thomas Jefferson, 1787

Isaac Newton (1643-1727) is the second member I'm discussing of Thomas Jefferson's "trinity of the three greatest men the world had ever produced." There is some irony in the inclusion of Newton in that group, because in his religious writing Newton took an anti-Trinitarian position, one that he was discreet about making known publicly. Jefferson also held an anti-Trinitarian view, so we could speculate that may have been a factor in his particular admiration for Newton. But it's likely his scientific work is what particularly impressed Jefferson.

William Blake's vision of Issac Newton 

Newton is of course known for the theory of gravity. Which, for our science-denying, anti-evolution Republican friends, I should note is "just a theory." He is also known for his three laws of motion, his theory of optics, and the discovery of calculus. He shares credit for the latter with his German contemporary Gottfried Wilhelm Leibniz (1646-1716). Who deserved how much credit for the latter was the subject of some lively dispute in Newton's and Leibniz' lifetimes.

Newton's theory of gravity enabled a better understanding of the rotation of the planets around the sun and to understand that those orbits were elliptical.

A popular misconception about Newton, particularly heard among the esoteric/New Age crowd, is the claim that Albert Einstein somehow proved that Newton was wrong. This is a broad claim, and a groan-inducing one to those more familiar with the history of science. It generally is put in the context of the Newtonian theory of gravity. But you can try it for yourself. Take one of those apples that legend has it gave Newton a flash of revelation about gravity. Drop it. Drop it several times. It still falls to the ground.

The main difference between Newton's theory of gravity and Einstein's was better telescopes. Newton discovered how gravity works and build a scientific theory to explain it. Einstein observed phenomena that the telescopes of Newton's time couldn't detect and built theories to explain those. Fundis are fond of fusing the English colloquial meaning of "theory" with the meaning of "theory" in science and saying, "Evolution is just a theory." As in, evolution is just a guess.

Pete Seeger used to keep a bumper sticker in his house that said, "Gravity is just a theory." I don't recommend trying to walk on air from the tenth story of a building on the assumption that gravity is an unproven theory. Or that Newtonian gravity has been abolished.

Newtonian gravity works well in the solar system, though there is some tiny variation in the orbit of the outer planets that the Newtonian theory of gravity doesn't completely explain. But the fact that Einstein discovered that gravity exists because spacetime is curved doesn't mean Newtonian science or his theory of gravity were wrong. Eistein's theories of relativity were a broader theory that include Newtonian gravity but are based on better telescopes. And presumably on mathematical developments that Newton facilitated as well.

Newton's most important work is the Philosophiae Naturalis Principia Mathematica, which the Britannica article on Newton edited by Newton biographer Richard Westfall calls "not only Newton's masterpiece but also the fundamental work for the whole of modern science." (Westfall's 1980 biography of him is is Never at Rest: A Biography of Isaac Newton).

Martin Gardiner in "Isaac Newton: Alchemist and Fundamentalist" Skeptical Inquirer Sept/Oct 1996, summarized Isaac Newton's accomplishments this way:

For several centuries the best-known Newton has been the great mathematical physicist who in his early twenties invented calculus, discovered the binominal theoren, introduced polar coordinates, proved that white light was a mixture of colors, explained the rainbow, built the first reflecting telescope, and showed that the force causing apples to £all is the same as the force that guides the planets, moons, and comets, and produces tides. His discoveries revolutionized physics.

Hegel considers Newton's empiricism as halting itself at the point where genuine philosophical reflection begins. He calls the Principia "a writing that contains only the methodology of finite science through observation and conclusion." (p. 805) From a materialist philosophical perspective, of course, that is quite a lot! (Vorlesungen über die Geschichte der Philosophie [Lectures on the History of Philosophy ; I'm quoting here from the Bolland edition of 1908; translations mine])

Antonio Pérez-Ramos in "Bacon's legacy," The Cambridge Companion to Bacon (1996) notes that beginning with Scottish Enlightenment philosopher Thomas Reid, "from the very start the successes of Newtonian science was attributed to its author's faithful following of the rules laid down in the Novum organum some fifty or seventy years earlier. It is true that Newton does once refer to the 'argument from induction'". In other words, Newton was generally seen as a philosopher-scientist working very much in Bacon's tradition.

Hegel associated both Newton and Locke with "the English manner of philosophizing." And, in a bit of Hegelian humor, he explained this by interpreting Newton admonition to physics to guard itself against metaphysics as meaning, "Science, guard yourself against thought." (p. 919)

Newton thought very highly of his own accomplishments. This is not unusual among academics since, of course, though Newton perhaps had more objective justification for his faith in his work than most.

But though his theory of light has been validated by later work, he had something of a challenge in convincing his contemporaries. And that was in part because duplicating his prism experiment required clear and detailed instructions from Newton. And he found that a challenge to provide. He discovered that white light was composed of the various colors of the light spectrum that combined to form white light. He speculated that light was composed of particles. It took quantum physics and much better measuring instruments to determine that the components of light are photons, which both waves and particles.

Goethe worked with Hegel on light experiments, which led Goethe to intensely challenge Newton's theory of light and vision. Hegel agreed with Goethe's criticism of Newton. As Wolfgang Bonsiepen explains, Hegel rejected both the particle and wave theories of light, took light to be weightless, and in fact saw light as the opposite principle to weight. On of the key validations of Einstein's theory of relativity was the observation by 20th-century telescopes that light in fact curved, being affected by the gravity of heavenly bodies. ("Die Aktualitat der Hegelschen Naturphilosophie" Philosophische Rundschau 35:3; 1988)

Bonsiepen also speculates that Hegel must have been particularly attracted to the aspect of Goethe's theory that focused on the contrast between light and dark as an explanation of the refraction of light into colors, because it resonated with Hegel's concept of light as the opposite principle of weight.

Hegel also was skeptical of Newton's theory of gravity, not least because of a problem of which Newton was aware, which is that he had no convincing explanation of the mechanism by which gravity exerts a force on distant bodies. That problems was not solved until Einstein's theories of relativity showed how gravity is a function of the curvature of spacetime.


Wolfgang Bonsiepen, "Die Aktualitat der Hegelschen Naturphilosophie" Philosophische Rundschau 35:3; 1988

Martin Gardiner, "Isaac Newton: Alchemist and Fundamentalist" Skeptical Inquirer Sept/Oct 1996,

G.W.F. Hegel, Vorlesungen über die Geschichte der Philosophie (Lectures on the History of Philosophy) Bolland edition; 1908

Antonio Pérez-Ramos, "Bacon's legacy" The Cambridge Companion to Bacon (1996)

George Smith, "Isaac Newton" (2007) Stanford Encyclopedia of Philosophy

Richard Westfall, "Sir Isaac Newton" (2012) Encyclopædia Britannica Ultimate Reference Suite; 2014 Online version: "Sir Isaac Newton"

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