NEWTON and His “PRINCIPIA”
A DIALECTICAL WORLD CRUISE I
This is the continuation of a discussion of “Newton/Maxwell/Marx”, a new work of mine, from Green Lion Press. This overview has been envisioned as a “dialectical cruise”, visiting in succession the world-views of Newton, Maxwell and Marx. Here we visit the first of these “worlds”, that of Isaac Newton. Read part 1 here.
FIRST PORT OF CALL:
NEWTON and his “PRINCIPIA”
A FEW QUESTIONS ON ARRIVAL
The work known familiarly as Newton’s Principia is the foundation stone upon which our concept of science has been erected. Despite all the transformations by way of quantum physics and relativity, this bedrock image of objective, scientific truth remains firm. Arriving now, however, as if from outside our own world, we may feel a new sense of wonder, and presume to ask a few impertinent questions about core beliefs normally taken for granted:
Why, in our system of modern western science, do we suppose that the natural world is composed throughout of inert masses, with no inner impulse to move? Why are we convinced that nature is thus ruled by external forces, and that truth lies in finding mathematical laws of force?
In short, why do we suppose that nature is purely quantitative and, despite all appearances, deep down, essentially mechanical? Is the life we see everywhere infusing the natural world merely an illusion? Who killed nature?
These are dialectical questions, meaning that they go straight to the first principles of our systems of belief. Such principles normally go unquestioned, but challenging them is exactly our business here, on this dialectical world cruise! They all lead back to a fresh reading of Newton’s Principia. And as we shall be seeing in the course of this cruise, they do have interesting answers.
WHAT NEWTON WROTE: THE “PRINCIPIA”
What Newton actually wrote, and what the world has on the whole supposed him to have written, are two very different things, as we shall see. Let us begin, however, by taking Newton at his own word, with a thumbnail sketch of his Principia Mathematica Philosophiae Naturalis (“Mathematical Principles of Natural Philosophy”). In relation to this title itself, we might point out that Newton’s topic is by no means limited to the discipline we now call physics. Newton is prescribing for the entire natural world – the universe of objects, living or non-living, that meet our senses in the directions of the large or the small, by means of any instruments, however advanced, in any domain which assumes the role of science. The Principia is discussed in detail in the essay on Newton in Newton/Maxwell/Marx; here we give only a thumbnail sketch.
Newton builds his Principia in a geometrical mode with a clarity reminiscent of Euclid’s Elements. Like Euclid, he lays a secure foundation, now of definitions and laws of motion, from which propositions flow with the same intuitive conviction we feel as we follow Euclid’s Elements. A world is unfolding before our eyes; if the foundations are secure. The edifice must stand.
Newton thus builds an edifice of science as firm as Euclid’s, though crucially now this consists of nothing but inert masses, deflected from rest or straight lines only under the action of external forces. Bodies move according to strict, mathematical laws of motion, and the forces are defined by equally precise mathematical relations. All this unfolds in a structure of true and mathematical time and equally absolute, mathematical space. Within the Principia, Newton develops the range of all possible motions under central forces, and applies these results to describe with precision, as merely one possible case, the system of planetary motions about our sun. This beautiful result emerges as just one example of his universal method at work; he will go on, for example, in his Optics to provide an equally mathematical system of color and the visual spectrum. Where Euclid gave us the precise forms of the things of our world, Newton gives us the things themselves, though they enter strictly as quantities. Apart from inert matter whose measure is mass, there is nothing behind these mathematical forms.
This reduction to stark mathematics might well strike a modern reader as the very spirit of mathematical physics today, an account we might call mechanical. At this point, however, an important distinction arises. In fact, Newton writes in fierce opposition to mechanism.
Newton is responding to Rene Descartes, who had indeed described the world as mechanical – a plenum, each part acting on its neighbors by simple rules of contact. Once set going, the cosmos runs on its own, like a fine watch. God’s role at the Creation was as watchmaker, but since that moment, the cosmos has run, and will forever continue to run, on its own.
This exclusion of God from His cosmos is anathema to Newton, and motivates the Principia. Where Descartes had filled the heavens with ethereal mechanism, Newton sweeps the cosmos clean. And where Descartes had seen nature moving entirely on its own, Newton very deliberately cancels any such powers, leaving nature utterly inert, everywhere dependent entirely on the ongoing operations of God’s active law. Hence the introduction of law at the foundation of the Principia. The orderly motions of the planetary system, which Newton calls The System of the World, is for him a vivid testament to the wisdom and active power of God. To bring this vision to mankind is, he says in the Principia, the reason he wrote. Might we not add, it’s the reason the concept of law structures our scientific discourse today?
We see now, indeed, the answer to our question, “Who killed nature?” It was Newton! And we see, too, why he did it Newton made sure that nature would be strictly powerless, and thus fit subject for God’s continuing rule. Nature must be mathematical to admit the precision of divine rule. Force is the modality of divine command, and law enters physics as the voice of God, who speaks in the medium of mathematics. Scientists today who, in their opposition to “creationism”, may cite Newton as the founder of modern science, freed from religion, are assuredly calling the wrong witness!
THE “PRINCIPIA” WITHOUT GOD
Newton, then, intended his Principia as a testimonial to God’s active presence in His Creation. He thus writes as a theologian, but by the strangest of fates, has been read as a mechanician! How this happened is indeed a fascinating story, recounted in my Newton essay, but need not detain us long at this point.
Briefly, it turns out that Newton was dedicated experimenter and theorist in the realms of alchemy, and devoted much effort to detailed interpretation of scripture. It seems clear that for him the Principia itself was but one component of a far larger project. It appears that all this was regarded as an embarrassment by his executors, who took pains to sequester it from public view. In turn his denuded Principia was welcomed by a society more interested in science than in theology. A strictly mathematical world picture. Only in recent years have manuscripts been recovered, revealing the role of the Principia in a much larger, and very different, project.
Believing however that it was loyal to its mentor, the west has accepted embraced the structure of the Principia, with its assumption of nature as in itself inert, moved by forces defined by law, as if Newton had intended such a vision as the very truth of the natural world. We have conjured a Principia divested of God, a feat comparable perhaps to reading the Old Testament without mention of the Lord. We have an empty shell, a narrative with no plot, law with no lawgiver. The appearance of life, but assuredly, no role for life itself.
No one could doubt that modern science works; its success in its own terms speaks for itself, though the direction of its interests and the delimitation of its scope leaves room for important questions. Now that our dialectical inquiry has probed the foundations of our notion of modern science, which turn out to be curiously accidental, we are in a good position to ask, reasonably, whether some alternative, a different foundation for modern science, might be possible. As we shall see at our next port of call, visiting James Clerk Maxwell, the answer will be a resounding “Yes!” And nature will indeed spring to life once again, before our very eyes.
NATURAL PHILOSOPHY AS BEDROCK OF SOCIETY
Newton had fused natural philosophy and theology into one, truly apocalyptic vision. With that union dissolved, religion has been left to go its own way, with natural philosophy as the stark bedrock of our daily lives, our social and political associations, even our concept of freedom. We see ourselves as by nature separate and individual, while liberty becomes no more than the absence of restraint. At all levels, our associations are deliberate, held together by law in the form of agreements, to which we willingly bind ourselves for rational expectations of ultimate gain.
Our practical relationships thus rest ultimately on this understanding of the nature of nature – like Newton’s planets, we are separate bodies constrained by law, following trajectories in time and space. We group by aggregation; we are not social by nature.
In this world in which community is essentially an option, reasonable people can be heard to speculate that the brutality of war is part of our human nature. Despite all evidence, we find no place for life in the natural world: what appears as life we must accept, in scientific reality, as an artifact of complex mathematics – nothing real.
Religious convictions of course are another matter, not founded in nature but independently, in direct relation to the divine. The result, perhaps understandably, is that religious differences divide us even more fiercely than our perpetual struggle for the resources of the earth.
Surely there must be a better way – a more promising understanding of nature and natural philosophy. And indeed there is, as we shall see in our next port of call. Stay tuned!
This has been the first in a series of three ports of call in a Dialectical World Cruise. The second, to James Clerk Maxwell and his “Treatise on Electricity and Magnetism”, will appear in this space soon. Stay tuned – and meanwhile, your comments will be most welcome.