To the second edition of his Principia Mathematica, published in 1713, Isaac Newton appended what he called a scholium generale. A principal concern of Newton's had been to refute Descartes' theory of planetary motions, which he renounced as a materialistic theory. The perfection and the regularity of these motions cannot "have their origin in mechanical causes," Newton insisted. "This supremely exquisite structure that is visible to us, comprising the sun, the planets, and the comets, could come into being solely through the decision and under the dominion of an intelligent and powerful, truly existing being.... He steers everything, not as a world-soul, but as the Lord of all things."
Indeed, Newton added an energetic remark directed against the deism that was already rampant in the early eighteenth century: "A God lacking in dominion, providence, and final causes is nothing other than mere late and mere nature. No possibility of change in things may be derived from blind metaphysical necessity, which is after all always and everywhere the same. The entire manifold of things ordered according to place and time could originate solely from the ideas and the will of a truly existent being, one that exists as a matter of necessity." And this section of the scholium doses: "So much, then, about God; to make assertions about Him on the basis of natural appearances pertains directly to natural philosophy."
Newton's scholium contains, in a nutshell, many of the essential questions that still occupy us today when discussing science, reason, and faith. Yet already in Newton's view of divine action a major shift from the Aristotelian and medieval understanding has taken place. In the traditional view, the Creator endows nature with a kind of quasi-intelligence: Like an agent, nature "acts for an end," with immanent principles of self-unfolding and self-operation. Newton, by contrast, is already seized by the early modern "mechanical philosophy," in which nature is seen as a kind of unnatural composite of passive, unintelligent, preexisting matter, on which order has been extrinsically imposed by a Supreme Intelligence.
Some of the passion of these concerns about science, reason, and faith came to vehement expression after my publication of an article on the topic in the New York Times on July 7, 2005. A debate about whether, for example, a newly discovered manuscript contains an authentic work of St. Augustine or not stirs passionate debate, but such a debate is relevant only to a small circle of the initiated. The question whether the universe and the place human beings have within it owe their origin to blind chance or to a supremely wise and good plan arouses us all.
Assume for the moment that--as many modern scientists believe--science arrives at the conclusion, on the basis of its methods of investigation, that everything is the result of a blind game of chance and necessity. The religious answer to the fundamental questions of human existence then seems to become groundless, a free-floating garland asserted without justification. If the assertion that the world arises from a plan, from the setting of a goal by the Creator, were to turn out to be scientifically baseless, then faith in a Creator and his Providence would be irrational, based at best on a credo quia absurdum. And a belief built on an absurd basis is not belief but an illusion, of the sort that Sigmund Freud and so many others have tried to expose and destroy.
Newton's scholium generale frames beautifully the modern version of this debate. For him, the evenness of planetary orbits is a phenomenon that does not permit of an explanation based on mechanical causes. This elegantissime structure can have originated solely through the decision and dominion of a supreme intelligence. Based on the phenomena of nature, one attains to certainty about the Creator.
Indeed, Newton goes even further, arguing that the multiplicity of objects cannot originate from the blind play of coincidence and necessity. Conventional evolutionary theory today declares the exact opposite: The entire range of species has originated through the undirected play of the forces of mutation and selection. For Newton, the entire range of objects derives its origins solely "from the ideas and the will" of the Supreme Being. And this is for him a certainty that he derives from his researches.
But there was a problem lurking in Newton's argument. He assumed, in this account, that God's providence repeatedly intervened in order to secure the stability of planetary orbits and of the solar system. In the absence of such repeated special divine intervention, Newton's mathematical calculations indicated that the planetary orbits would be unstable and quickly devolve from order to chaos.
Newton's equally brilliant interlocutor Leibniz took Newton to task for the notion that it was necessary for "God to wind up His watch from time to time." According to Newton's outlook, God's work was "imperfect in a manner that requires Him to clean and even to repair it from time to time, just like a watchmaker must do with 'His work.'" Leibniz held this to be a diminution of the omnipotence of God, and he argued instead for a "sublime pre-stabilized order" in which alone the wisdom and power of God is manifested.
We know that Leibniz's view was thoroughly vindicated within a century. The great physicist Laplace, with a great deal of additional data about the solar system and a better-developed mathematical physics of celestial mechanics, was able to provide a purely mechanical explanation for the orbits of the...