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Retrospections History Plurality of Worlds
 
Plurality of Worlds
"As in the daytime there is no star in the sky warmer and brighter than the sun, likewise there is no competition greater than the Olympic Games". --Pindar, Greek lyric poet, 5th century BC
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Cosmic Evolution
Posted:   08/10/04
Author:    Astrobiology Magazine staffwriter

Summary: Did the same Greek philosophers who declared the first truce for Olympic competition have the foresight to imagine a universe not just where many countries could coexist, but also a universe occupied by many such habitable worlds?
equestrian
Olympic equestrian events represent the main intra-species competition to supplement the inter-country rivalries. Horses and humans compete together in the Olympics.

The Summer Olympics in Athens begin Friday. More than two thousand years ago (776 BC) the first Olympic Games were held in Greece. When the Modern Games were revived in 1896, founder Pierre de Coubertin again chose Athens as the host city. In 2004, the games will return to their birthplace for only the third time (the 28th Olympiad) and the event offers a chance to memorialize the beginnings of a self-conscious Greek view of its place not only in the world, but in the universe.

The Greek aesthetic took the worldview that humans are the measure of all things, thus creating Western civilization, but this bias may have muddied a question of other worlds, where humans are off the scale.

As an unbroken chain linking the plurality of countries, the trademark interlocking five rings of the modern Olympic movement represents the five continents. By the same token, a similar chain of thought stretches back to the first Olympics, two millenia ago, when Greek thinkers speculated about a plurality of worlds.

While few would question the existence of the many flags and countries that the Olympics rings encircle, there has been considerable contention surrounding a less earth-centered competition. Philosophers were the first natural scientists: Aristotle, Democritus, Epicurus and Pythagorus.

Their debates were fiercesome, like athletic contests of philosophy.

Flagging the Many Philosophies

Locked in conflict were the many schools of thought, some like the Epicureans claiming the Earth was not the only planet occupied by life forms and others like the followers of Aristotle and Plato who argued that 'if creation was a composite, it would be subject to dissolution and decay.'

The writings of Aristotle [384-322 B.C.) present an array of arguments against astrobiology and the modern picture of innumerable, Earth-like worlds. Foremost because our solar system's motions were directed by a Prime Mover on the outskirts of the farthest planet--at that time, Saturn--then multiple solar systems would require multiple Prime Movers--an idea that Aristotle rejected as philosophically and religiously unacceptable.

Aristotle's position did not go unchallenged. Like a battle of Olympic philosophers, the Epicureans and Pythogoreans all had their chance to enter the ring. Concerning the structure and evolution of the universe, the most influential Epicurean proponent was the Roman poet Lucretius (99-55 B.C.) who asserted:

"Granted, then, that empty space extends without limit in every direction and that seeds innumerable are rushing on countless courses through an unfathomable universe...it is in the highest degree unlikely that this earth and sky is the only one to have been created and that all those particles are accomplishing nothing."

Image of star HD 28185
HD 28185 b is the first exoplanet discovered with a circular orbit within its star's habitable zone. Astrobiology: the study of how life begins and evolves - that is, where did we come from? Does life exist elsewhere in the universe - are we alone? And, what is life's future on Earth and beyond - where are we going in space
Credit: STScI Digitized Sky Survey


This point of view was given new relief when the fifteenth century scientists, particularly Isaac Newton, rediscovered Lucretius's poem and the Epicureans' world-view. Their response was to formulate the laws of physics by explicitly stating a defining reference frame. Motion was defined from a central axis that itself can move.

Echoing Lucretius, this same sentiment was revisited in the popular imagination in the film, Contact, based on Carl Sagan's novel, when the astronomer, Dr. Ellie Arroway, repeats the Epicurean question, " do you think there's people on other planets?" To this question, Arroway's father, Ted, replies, "I don't know, Sparks. But I guess I'd say if it is just us... seems like an awful waste of space."

The Epicureans did not have a simple view of these other worlds. Plurality of worlds can mean many planets-- or a succession of one planet over time. In Greek astronomy, the sky was a vault. A dome surrounded the farthest known planet in our solar system. The Epicurean worlds were plural, but these separate systems were unseen by humans. So stars, suns and planets could exist as conglomerates within the uncuttable atoms. As Metrodorus of Chios, a contemporary of Epicurus and his leading disciple, put it, "It would be strange if an ear of corn grew in a large plain or were there only one world in the infinite. And that worlds are infinite in number follows from the causes [i.e., atoms] being infinite."

Even more radical views from antiquity were expressed by the Pythagoreans, such as speculation that our moon is currently inhabited: "the moon is terraneous, is inhabited as our earth is, and contains animals of a larger size and plants of a rarer beauty than our globe affords. The animals in their virtue and energy are fifteen degrees superior to ours, emit nothing excrementitious and the days are fifteen times longer."

The Pythagorean speculators were notable not only for their quantitative flavor (the lunar animals as fifteen percent but not twenty percent superior?). More revolutionary even today, the Pythagoreans concluded that earth might not offer the best place for humans to live.

Not to be satisfied with only speculation and hypothesis, Lucian of Samosata (120-200 A.D.) composed two fictional moon voyages to do what today might be called, 'the astrobiological hardwork' of looking and testing.

olympics
As an alien might receive the Olympic TV broadcast, featuring carbon-based bipeds who appear to walk using two limbs while balancing precariously in a semi-upright posture but may be evolving rudimentary transportation systems based on the wheel. Credit: Australian Broadcasting Corp.

 

Competing and the 'No Fear' Advantage

Underlying this debate may be implict a fear of earthly neglect if other worlds are found. The Epicureans fundamentally rejected this notion with their theme, "freedom from fear".

As science-fiction writer, Ben Bova, described, "Shock and awe, at first, among the general population [will greet an announcement of life elsewhere]. Then, as they see that the world is not coming to an end, they will gradually accept the idea that we are not alone in the universe. For scientists, the great question will be to determine if extraterrestrial life comes from the same origin as our own, or has arisen independently."

Western scholars would later reject the debater's points--whether the succession of worlds from the Stoics, the multi-world view of the Epicureans or the habitable moon theory of the Pythagoreans. The philosophers of the Middle Ages did however acknowledge a central place for the question itself: does life exist elsewhere?

Albertus Magnus (1193-1280) crafted one of the first statements that could easily be recognizable on an astrobiology roadmap today: "Since one of the many wondrous and noble questions in Nature is whether there is one world or many,...it seems desirable for us to inquire about it."

While most of Aristotle's intellectual descendants cut short the debate, the famous Oxford-educated, Franciscan, William of Ockham (1280-1347), argued the same question: could the First Cause create multiple worlds? To answer, Ockham relativized Aristotle's antipluralism, since the notion of natural place between earth, air, fire and water could translate their elemental properties to a different natural place at different locales. In other words, just as trees and wood can rise in water (in violation of strict natural place), different planets might not provide the same relation between heavenly air and fire or terrestrial soil and water.

Even if Aristotle might have described Terra Firma, he still could consistently be generalized to Extra-terra Firma. This logic trick satisfied Ockham's razor, the law of parsimony, because it was a simple explanation.

Just as a rich, two millenia tradition underpins the gathering of many nations under the Olympian five rings, today's view of the universe has aggregated a consensus around the many world view of our universe. The debate is governed more by statistics than philosophy, with echoes of Metrodorus' poetry ("it would be strange" to imagine just one world). But one cannot discount the debate itself, since the same competition is open today about whether multiple universes, or multi-verses, might or might not be possible. Just like the Greeks, such modern scientific forums debate the boundaries to, well, everything.

Statistics Trumping Philosophy?

Star field
The statistical argument for life elsewhere may trump philosophical purity
Credit:NASA/STScI/ ESA


Ockham's razor offers an ironic twist on this debate. Ockham's rule in science and philosophy is often cited in defense of multiworlds. But the rule technically states that entities should not be multiplied needlessly. This definition sounds like Aristotle: the Prime Mover is not otherwise occupied by attention to other habitable planets. We as the one are alone.

In the more modern parsimony, however, the philosophical razor is sought to cut between competing theories, where the simplest explanation wins. Simplest in this case means requiring the fewest presuppositions or assumptions. The race is won along the shortest foot path.

As CUNY Professor, Michio Kaku, noted, for the first time in history, experiments may offer the shortest path to resolution. The scientific method can settle this two millenia-long debate: "This question is no longer a matter of idle speculation. Soon, humanity may face an existential shock as the current list of a dozen Jupiter-sized extra-solar planets swells to hundreds of earth-sized planets, almost identical twins of our celestial homeland."

If other worlds are the central laboratory for astrobiology--or the selected site for a new scientific Olympics among researchers--then its interlocking five rings represent the needed elements for life itself: one ring each for water, air, soil and temperate fire--all held together by enough time for biology to take hold. That combination would indeed be the Olympic moment.


Related Web Pages

Night Lights
Eavesdropping on Olympus
The Earth as Seen by Galileo

Blue Dot, Red Planet
Life in the Clouds
Commitment to Life on This Earth
Frequent Wet Earths?
Defining Life
Entropy and Evolution
What is Life?


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