The ancient Greek philosopher Parmenides of Elea believed that reality was timeless, unchanging and indivisible, all appearances to the contrary notwithstanding. To buttress this contention, Parmenides’ pupil Zeno put forward a series of paradoxes designed to prove that all apparent multiplicity and motion were illusory. Among nine surviving paradoxes preserved in Aristotle’s Physics, Zeno argues that an arrow in flight cannot really move because at any given instant it can only occupy a space equal to itself. An object that occupies only a space equal to itself is at rest; therefore, an arrow in flight at any given moment must be motionless, a fundamental contradiction that ostensibly proves Zeno’s point.
Mathematicians and philosophers have been trying to poke holes in Zeno’s arguments for some 2,500 years. Mathematicians insist that the paradoxes are really mathematical problems that are solvable using calculus, which didn’t exist in Zeno’s day. As for their philosophical implications, I am partial to Peter Lynd’s argument that the issue is not whether motion exists but whether instants of time exist. Time, by definition, has duration, whereas an instant does not, nor do any number of instants put together constitute duration. An instant is an abstraction that proves nothing about an actual arrow in flight. Aristotle and Thomas Aquinas had previously raised similar objections. Those who are not philosophically or mathematically inclined may prefer the argument put forward by Diogenes the Cynic, who demonstrated that motion existed simply by standing up and walking.
Heraclitus, another pre-Socratic philosopher and near contemporary of Zeno, also tackled the problem of change and arrived at the opposite conclusion (“No man ever steps in the same river twice”). Yet Zeno’s position is the one that philosophers have been gnawing on ever since, if only to formulate a definitive rebuttal. For the Greeks, the highest truths were mathematical. However, lacking a mathematical solution to the problem of motion, they tended to gravitate toward philosophical principles that were unchanging. Although neither Plato nor Aristotle ever fully subscribed to Zeno’s position on change, they shared his view that outward appearances cloaked a deeper reality. For Plato in particular, the world we live in is a pale copy of an objective realm of pure form that is transcendent, eternal and perfect. As he said of beauty, so it is with all form: it is "everlasting; it neither comes nor goes, neither flowers nor fades."
Christianity was a Jewish offshoot planted in Greek cultural soil. Although St. Paul was generally disdainful of the Greeks, later church fathers were more receptive. St. Augustine, a Christian convert, began as something of a Neo-Platonist and believed that the mind of God contained timeless forms that existed apart from the created order. Thomas Aquinas, the theologian who did more than anyone else to meld Christianity with Greek philosophy, maintained that God was, in effect, timeless, unchanging and indivisible.
Parmenides had made the mistake of assuming that for a truth to be eternal, it must also be unchanging. His pupil Zeno compounded the mistake by using clever arguments to divorce truth from what we commonly think of as reality. A similar dynamic would seem to apply in the current battle between religion and science. You wonder how things might have turned out if we had just paid closer heed to Heraclitus, Zeno’s near contemporary, who said you can’t get your feet wet in the same river twice. Heraclitus understood that truth is not fixed but fluid. Certainly the God in whom we live and move and have our being, to borrow a phrase from St. Paul, is not unchanging but eternally new.