Newton’s occult belief in ‘action at a distance’ has been suppressed by historians seeking to deny that magical ideas played a major role in the development of modern science, argues John Henry.
“Action at a distance” was a designation used since the Ancient Greeks to refer to any action between bodies which did not take place by contact action. Aristotle, whose natural philosophy was the most influential on later Western thought, insisted that a body could only act on another body by hitting it, sticking to it, combining with it, or some other kind of contact action. This view held sway throughout the Middle Ages thanks largely to the endorsement of Aristotle by Thomas Aquinas. It was Thomas who summed it up in the often-repeated phrase, “a body cannot act where it is not.” The advent of the new “mechanical philosophies” in the seventeenth century only reinforced contact action. The mechanical world picture was one of cogs tyrannic, intermeshing with, and grinding against, one another, with no spaces between.
There were always those, however, who believed in the “evil eye”, or in other forms of immaterial influence. In the occult tradition bodies could act on one another at a distance by non-material means, by supposed virtues, powers, or forces. Even the Aristotelians had their doubts with regard to magnets, which could not only attract pieces of iron but could do so through stone or a substantial sheet of lead. The mechanical philosophers, undaunted by inconvenient observations, simply assumed magnets sent out streams of invisible particles which could hook themselves on to a piece of iron and return to the magnet, dragging the iron with them. Not even magnets had occult powers of attraction, the mechanists insisted, they operated by indirect contact, thanks to their streams of material effluvia.
All this was changed, however, by Isaac Newton and the unprecedented success of the new physics he presented in his Mathematical Principles of Natural Philosophy, the Principia mathematica of 1687. One of the most remarkable aspects of Newton’s physics is that it not only assumed the reality of actions at a distance (chiefly, but not exclusively in the case of gravity) but it also established actions at a distance as a mainstay of physics throughout the eighteenth century and into the nineteenth. Newton’s influence in this regard was so great that by 1843, when John Stuart Mill published his System of Logic, he was able to write that nobody now “thinks it at all incredible that the celestial bodies can and do act where they, in actual bodily presence, are not.” He dismissed the shared view of the Aristotelians and the Cartesians (followers of René Descartes, inventor of the most successful version of the mechanical philosophy) as very much a thing of the past:Rather more than a century and a half ago it was a scientific maxim, disputed by no one, and which no one deemed to require any proof, that ‘‘a thing cannot act where it is not.’’ With this weapon the Cartesians waged a formidable war against the theory of gravitation, which, according to them, involving so obvious an absurdity, must be rejected in limine: the sun could not possibly act upon the earth, not being there.
Newton had been coy at first because he knew action at a distance was such a magical and untenable position.
Newton had been coy at first because he knew action at a distance was such a magical and untenable position. The first edition of the Principia, accordingly, discussed gravity as an attractive force but did not explicitly spell out that bodies were therefore acting on one another at a distance. Major representatives of the mechanical philosophy were not fooled, however. Newton’s great rival, G. W. Leibniz accused Newton of reintroducing occult qualities back into natural philosophy, after they had been so brilliantly excluded by Descartes. For Leibniz, the Newtonian concept of gravity was “an unreasonable occult quality, and so very occult, that it is impossible it should ever be clear, though an angel, or God himself, should undertake to explain it.” In spite of such criticisms, Newton was emboldened by the success of the Principia, and explicitly invoked actions at a distance in his second book, Opticks (1704, and expanded in Latin in 1706). In the final revision of the Opticks, in 1717, for example, Newton suggested that “the small Particles of Bodies” have “certain Powers, Virtues, or Forces, by which they act at a distance, not only upon Rays of Light… but also upon one another for producing a great Part of the Phaenomena of Nature” (Opticks, Query 31). From then on, actions at a distance were no longer confined to magical traditions but increasingly came to be seen as fundamental to mainstream physics.
In spite of the great achievements of Newtonian physics and the supreme authority of its author, however, this state of affairs did not last. During the 19th Century Newton’s dynamic atomism, in which atoms were endowed with attractive and repulsive forces, was replaced, for example, by the so-called kinetic theory of gases, in which atoms were deemed to be passive and inert (that is to say, devoid of any virtues, powers, or forces) except that they were in continual random motions. What Newton had explained in terms of repulsions were now explained in terms of the continual rebounds of particles from one another and from the walls of their containers. More generally, the idea of action at a distance came to be seen once again as occult and therefore unacceptable. This culminated in Einstein’s famous opposition to what he called “spooky action at a distance” and his explanation of gravity in which there was no attractive force operating. According to Einstein, there was no invisible immaterial connection between the Sun and the planets; the Sun bent the fabric of space-time and planets found themselves running down the gradient. Newton’s apple was not attracted to the Earth; the Earth distorted space-time so that the apple, once separated from the bough, could not continue to occupy the same part of space.
Action at a distance came to be seen once again as occult and therefore unacceptable. This culminated in Einstein’s famous opposition to what he called 'spooky action at a distance'
The full story of the rejection of Newtonian actions at a distance throughout the nineteenth century is wide-ranging and complex, but it is highly ironic that one of the factors in their demise was Newton’s own authority—used unwittingly by later thinkers against Newton himself. A series of letters from Newton to the Anglican Churchman, Richard Bentley, which had been published in 1756, was re-published in 1838 in a collection of some of Bentley’s works. Subsequently, a single passage in these letters became, in the latter half of the nineteenth century, the most frequently quoted statement by Newton. Publicised especially by Michael Faraday, it was certainly instrumental in turning Faraday from a good Newtonian dynamicist into a scientist who insisted that lines of force must be reduced, as James Clerk Maxwell (following Faraday) said, “to a phenomenon of the same kind as that action at a distance which is exerted by means of the tension of ropes and the pressure of rods.” In other words, there is no action at a distance, because, as the mechanical philosophers of the 17th century used to insist, there is some invisible but nonetheless material connection between the interacting bodies. For the mechanical philosophers, the bodies were connected by streams of material particles, for Faraday they were connected by “physical” lines of force, which Maxwell likened to ropes and rods.
So, how could Newton’s authority be used to counter the action-at-a-distance physics of his own Principia? While helping Bentley to use Newton’s physics to prove the existence of God (which is what the letters were about), Newton wrote at one point:
That Gravity should be innate, inherent and essential to Matter, so that one Body may act upon another at a distance thro’ a Vacuum, without the Mediation of any thing else, by and through which their Action and Force may be conveyed from one to another, is to me so great an Absurdity, that I believe no Man who has in philosophical Matters a competent Faculty of thinking can ever fall into it.
This looks unequivocal and it is no wonder that Faraday thought that his much-admired hero had rejected the kind of physics to which Faraday himself had been subscribing—namely a physics of actions at a distance.
If read in context, however, Newton’s objection here is not to action at a distance per se, but to the idea that bodies might act a distance without God endowing them with the ability to do so. His objection is to the idea that gravity should be essential to matter, the way, for example, extension is. Matter cannot exist without being extended, and so extension is essential to it. Matter can exist without the power of gravitational attraction, however. And yet Newton has proved beyond doubt in the Principia that matter gravitates. This could only be possible, he believed, if God had given matter this extra power; therefore God must exist. The existence of gravity proved the existence of God. We know this is what Newton intended, firstly because it is the way Bentley himself presents this in the lecture he was writing (advice about his lecture was the very reason he had written to Newton). As Bentley said in his lecture: “’tis unconceivable, that inanimate brute matter should (without a divine impression) operate upon & affect other matter without mutual contact.” It is inconceivable that matter should affect other matter without contact, without a divine impression. For both Newton and Bentley, matter could act at a distance if and only if omnipotent God made it so. Secondly, we know Newton must have intended this passage this way, because just over a decade later he went into print in the Opticks speaking freely of actions at a distance (to say nothing of the fact that, as Leibniz and others pointed out, the Principia had already taken actions at a distance for granted).
It is clear that Faraday, Maxwell, and the other scientists who quoted this passage from the letter to Bentley of February 1693, were unaware of Newton’s formative role in the history of action-at-a-distance physics which they now found themselves trying to shake off. This is understandable; for all their admiration for Newton, they were practising scientists grappling with the pressing scientific problems of their day and felt no need to look back to books published a century and a half earlier. Unfortunately, no such defence can excuse the fact that a number of historians of science specialising in the work of Newton have also insisted, against the historical evidence, that he never accepted actions at a distance. They treat the passage from the letter to Bentley as unassailable evidence for their position and do not even take the trouble to explain away clear statements to the contrary by Newton, such as:
Pellucid Substances act upon the Rays of Light at a distance in refracting, reflecting, and inflecting them, and the Rays mutually agitate the Parts of those Substances at a distance for heating them; and this Action and Re-action at a distance very much resembles an attractive Force between Bodies (Opticks, Query 29).
Evidently, Newton did not repeat the crucial phrase “at a distance” often enough to get through to these modern readers.
The enormous resistance of these historians to the idea that Newton might have believed in the concept of action at a distance seems to be a late manifestation of the broader resistance to other historians’ claims that magical ideas and beliefs played a significant historical role in the development of modern science. It is now generally accepted that Newton was thoroughly immersed in the theory and practice of alchemy; but for many years the undeniable evidence of this in his papers, and in the reports of his contemporaries, met with similar resistance. The battle among historians over the relevance of Newton’s alchemy has been won, and there are now serious historical studies of his alchemy, its background, and its context. There are, however, plenty of Newton scholars who continue to insist that he never could or would have believed in so obviously occult a notion as action at a distance.