Mere Gravity

by Paul Arveson

Over 250 years ago Newton formulated the law of gravity, namely that there is a force between any two objects that varies as the inverse square of the distance between them. He also discovered the related principle of the equivalence of inertia and acceleration.

It seems incredible that this simple mathematical relationship is responsible for such a vast range of phenomena as these:

With the addition of one more fact (also known by Newton) -- the finite speed of light -- gravity predicts the existence of even more exotic phenomena:

Astronomers have recently discovered a rogue supermassive black hole, formed in the early history of our galaxy, that has been observed because it is orbited by a companion star that is gradually being consumed by the black hole. Fortunately, this object is 6000 light-years away from us, but it is orbiting far from the center of the galaxy. It may be that there are other such objects that remain undetected. If one of them were to pass nearby, the sun, the earth and the rest of the solar system could be drawn into orbit around it, spinning faster and faster, forming a disk of superheated vapor and eventually drawn into the black hole, to disappear from the universe forever.

The fact that gravity is an attractive force, without a repulsive force to balance it, implies that this fate may await every star in the universe, as gravity continues to draw every massive object towards another in a one-way trip to oblivion.

Intelligent Design and Gravity

A theist may readily be tempted to conclude that all these phenomena have been carefully designed by the Creator so that they behave in such intricate, diverse and beautiful ways.  In fact, that was the conclusion of Newton himself, when he first formulated the law of gravity.  But Newton felt that the simple formula was not sufficient; that something was missing: the small corrections needed occasionally to keep the planets in their orbits; to keep the earth in particular from falling into the sun.  So since he concluded that the earth has been here for a very long time, he took this as a proof of God's existence, and of God's intervention in the world to stabilize the earth's orbit.  Hence, the "God of the Gaps" theology was born. 

This "proof" was refuted about 100 years after Newton by another physicist, Pierre Simon de Laplace.  He found that actually the complex variations in the orbits of the planets are bounded and would not create long-term instabilities.  In a somewhat legendary story, as he was presenting his new text on Celestial Mechanics in the Emperor's Court, Napoleon asked him, "Where does God come into your theory?" and LaPlace replied, "Sir, I have no need for that hypothesis."  In this way, the active role of God in maintaining the universe was shown to be unnecessary; God was being kicked out of the world, and natural theology took a step backward.

But the whole Newtonian approach was based on unorthodox assumptions in the first place.  According to the Bible, God is not a mechanical, deist god, whether in or outside of the universe.  God is transcendent and immanent.  There are no gaps; God is everywhere (in a metaphysical sense) and nowhere (in a physical sense).  So physically speaking, the basic equation for gravity -- pure reductionism -- is quite valid and at the same time is not a refutation of God's existence.  Theists have no need for gaps to fill in the unexplained phenomena in the world. 

Nevertheless this quest for gaps continues today, with the Intelligent Design movement.  In one way it differs from the Newtonian approach: its focus is entirely on biology, not astrophysics.  But the motive is the same: to highlight gaps in scientific explanations in order to prove God's existence.  In the short run, many such gaps exist; biology is still a relatively young science -- we only sequenced the human genome a few years ago, and many more basic discoveries are probably around the corner.  But in the long run, I suspect that these gaps will be closed as brilliant scientists put their theories together and tackle the complexity of life.  If this happens, will we conclude that God has been replaced by evolution? 

The threat of evolution is just like the threat of gravity after LaPlace.  It only seems to be a threat if you have a deistic view of the nature of God in the first place.