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Lecture 5: Newton

Isaac Newton: 1642-1727

Newton, the physicist

As a physicist, I have perhaps underestimated Newton, because I did not realize how important his many contributions to mathematics and geometry were. More to the point, I have disparaged the emphasis in 1st year Physics curricula on "Newtonian Mechanics", commenting that it is really a mathematical introduction, not physics. Having read more of Newton's mathematical work, I can say that it is entirely appropriate that Newton's name be associated with mathematical aspects of physics, which despite his theoretical bent, emerged in his ability (rare among theorists) to make careful experimental measurements to confirm his theories.

Unlike Galileo, Newton does not seem to have the same hubris, the same desire to change the world. Almost all of his publications came years, if not decades, after they were first presented in his lectures, and often at the insistent urging of friends. His early work on optics at Cambridge was attended with much controversy which seemed annoyed Newton a great deal. He couldn't bear seeing the quality his work doubted. Much of Newton's work was published anonymously out of Newton's subsequent avoidance of controversy. In the later decades of his life, he was embroiled in an argument with Leibnitz as to who developed calculus first. One historian says that Newton was scrupulously accurate, but not generous with others and took offense easily. Having met physicists with many of these identical characteristics, I can easily see Newton's personality in the memory of a graduate student who worked 18 hour days and then slept 7 hours, resulting in a time schedule that slipped by an hour a day, so that one could often find him roaming the halls in the wee hours of the morning. Like Newton, he did not suffer gladly the company or criticism of fools. It is genius, but fragile genius, that perhaps accounts for his illness at age 50 and the waning of his powers. Unlike Galileo or Einstein, Newton's reputation evidently grew with time, and mathematicians of later centuries marvelled at his geometrical acumen.

Newton, the metaphysicist

What interests me most, however, is not the sheer ability of Newton to generate mathematical results, but the metaphysics that he employed. This is the topic that Brook touches on in his book, noting that Newton required a special dispensation to study at Trinity College when he decided he could not assent to the 39 Articles, the confessional statement of the Anglican Church. Newton, whatever his faults, always wanted to keep his conscience clear, and to the great embarassment of future generations of scientists, spent the last decades of his life writing theology, or more precisely, a defense of his Unitarian beliefs.

Now this is significant for several reasons. First, one's metaphysics does not arise in a vacuum. Nor does it appear preformed from the mouth of one's teachers. Rather, everyone develops their own peculiar flavor of metaphysics as they attempt to make sense of the world around them, and their part in the universe. Often a traumatic event in childhood will be encapsulated in some quirk of one's metaphysics. For example, Einstein's celebrated remark about the unreasonableness of Bohr's Quantum Mechanics was "God doesn't play dice." Clearly, games of chance were abhorrent to Einstein. Contrast this position with Darwin who saw in "Chance" the impersonal working out of evolutionary advance. Why do these two, essentially modern scientists, have such opposite metaphysical attraction to chance? One possible explanation, though by no means exhaustive, might be their respective upbringing.

A second motive for one's metaphysics is harmony with one's life and lifestyle. For example, Flannery O'Connor writes novels about people who are highly conflicted, who preach one message but practice another. These dissonances are highly stressful, leading such people into contradictory and unpredictable behavior. Usually one either adapts the practice to the preaching or the preaching to the practice. It is so common as to be a mark of a cult when the cult leader finds some religious justification for some otherwise common vice.

So applying these principles to Newton, what connection do we find between his Unitarian theology, expressed early in his career at Cambridge, with his metaphysics of gravitation? Stanley Jaki has argued, as I have said earlier, that the medieval synthesis achieved modern science because it was able to balance the hypothetical science with the belief in the existence of a real external world. In Newton's case, this led to a careful path between Scylla and Charabdis, between the atomists who rejected "forces" and the magicians who invoked "souls". Logically, the extreme positions are always the easiest to defend. But Newton insisted on gravitation requiring "spooky action at a distance" while simultaneously rejecting organic metaphors for such attractive forces.

To us moderns, this balancing act seems as difficult as walking while chewing gum, but for Newton it required some peculiar metaphysics. Remember, whereever he looked, whether it be the proverbial apple or the Moon in the sky, he discovered the same law of acceleration, an acceleration that only really only made sense when one adopted the language of the calculus. Why should "acceleration", a non-intuitive mathematical construct, possess such universal, ubiquitous and unchanging attributes? Aristotle would have said that it was in the psyche or soul of the object that one should look for these attributes. The Medieval scholastics would put the attributes in the mind of God. Newton found it in the power of the mathematical description of reality. What is a velocity but dx/dt, the change in position with change in time? And what is an acceleration but dv/dt, the change in velocity with change in time? And if these are to have unchanging qualities for all bodies in the universe, then must not the units, the space, the time, be also unchanging? Thus he felt that it was space, time and matter that formed the Eternal Truth (much as the Greeks had posited 1500 years earlier), requiring neither the spirit of objects nor the will of God. But now Newton had a problem.

If the eternal trinity for Newton became space-time-matter, then he had already been condemned by the medieval church, which said such Aristotelian concepts were unchristian and unacceptable. Bruno had been burned for beliefs such as these. So we see Newton at the cross-roads we mentioned above, and he chose the path of adapting his theology to his metaphysics. Since the medieval church had formed its opinions on the critique of St. Augustine, clearly, Newton must have felt some animosity for this early church father. In rejecting Trinitarian doctrine, Newton may have been trying to drive a wedge between the Holy Scriptures, and the wholly medling of Augustine. If this assumption is correct, then I can almost see Newton, satisfied that his life output of mathematics was published and summarized neatly, going back to his college days and wanting to tie up that loose end of his youth. Newton would have written those theology books to absolve himself of the criticism of apostasy, just as I watched my graduate colleague working late in the night on an obscure integral.

Jaki would say that it was Newton's fundamentally Christian metaphysics that enabled him to propose the theory of gravity. The Enlightenment skeptics would seize upon Newton's rejection of the Trinity as the first step toward enlightened atheism, along with his mechanization of the celestial spheres. Yet that peculiar drive to exonerate oneself is an ethical drive, a moral drive, the crusade of an unjustly sentenced man. As C.S. Lewis was to say in this century, the opposite of theism is not atheism, for both of these views are about God; the opposite of theism is agnosticism, a profound disinterest in the whole affair. Newton shows all the characteristics of a man deeply concerned about God, attempting to fit God within his abiding faith in mathematics. For Newton, geometry was not only his forte, it was his faith.

As we will see, this shift of allegiance was to result in the anti-clerical atheism of the Enlightenment, as well as the "naive realism" that forms the basis of the modern metaphysics of "scientific naturalism". It is this 200 year metaphysical foundation that is so profoundly shaken by the 20th century physics we discuss later in this course. An earthquake that to my mind, should result in a radical restructuring of the way we teach physics, and the way we practice theology.

Last modified, January 24, 2002, RbS