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The overwhelming ambiguity of nothing—or empty space, as it is often called—is clearly reflected in the writings of the classical Greeks. In the Timaeus, Plato, anticipating much of the confusion to follow, doesn't know what to make of space. Space is not "up there" in the world of forms, but neither is it "down here," casting shadows on the wall. In Plato's colorful metaphor, space is "apprehended by a kind of bastard reasoning that does not involve sense perception … as in a dream."
Euclid's rhetoric is less stimulating than Plato's, but what it lacks in color it makes up in utility. For Euclid, space is a geometric object with a number of "self-evident" characteristics of endless utility, as we all learned in high school. But the vaunted clarity of Euclid's formulation failed to convince everybody. Parmenides' famous student Zeno, for example, showed that Euclid's concept of space was inconsistent with the idea of motion.
One of Zeno's classic arguments against motion runs like this: to get from here to there, one must first go halfway to there; but to get to this halfway point one must first go halfway to the halfway point. The space between here and there, argued Zeno, can be subdivided an infinite number of times. To travel from here to there requires that one traverse all these infinite subdivisions. But that would take an infinite amount of time. Thus motion is impossible. (One pictures Zeno pacing back and forth in a state of great animation as explicates this convoluted refutation of motion.)
Aristotle rejected the idea that space could be truly empty and convinced everyone that Mother Nature was truly horrified by nothing. For Aristotle, space could not be nothing nor could it simply be the "location for bodies" as Plato had taught. This would imply that bodies carried their "place" around with them. In the characteristically pedantic prose for which he is so universally loved by students of philosophy, Aristotle puts it like this:
If the place is in the thing (it must be if it is either shape or matter) place will have a place. For both the form and the indeterminate undergo change and motion along with the thing, and are not always in the same place, but are where the thing is. Hence the place will have a place.
Aristotle goes on to argue that "a place with a place" leads to an infinite regress, and thus we must abandon Plato's concept that the place of a body is simply its location. Space exists on its own, filled with "places" where things are constantly striving to be—heavy objects striving for lower places, flames striving for higher ones. And Mother Nature rushing in to fill any vacated place because she simply won't tolerate a vacuum.
For nearly two thousand years the Aristotelian tradition continued with minimal editing. The sixth-century philosopher John Philoponus criticized Aristotle's claim that the celestial spheres are not moving into new places as they rotate; in the fourteenth century Jean Buridan objected to the view that an object moves toward its natural place unless acted on by a force. In the seventeenth century we find Descartes defending Euclid's idea that space is a geometrical construct. We find Newton launching an attack on the Cartesians, arguing that "space" is physically real, a "disposition of being qua being."
Although Newton's notion of "absolute space" was rejected by his great contemporary and rival, Leibniz, not until two centuries later did Newton's theory receive a proper scientific critique. The critic was the Austrian physicist and philosopher of science Ernst Mach, whose work exerted considerable influence on Einstein. Mach mounted an attack on the idea of absolute space, which, he argued (correctly), was completely without empirical support. Absolute space, Mach said, was a product of Newton's "imagination," and should play no role in any physical theory, since good theories are based on sense observations. (Mach died in 1916 refusing to believe in atoms because he couldn't see them.)
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