God: The Failed Hypothesis (18 page)

²⁵
Stenger,
The Comprehensible Cosmos.

²⁶
E. Noether, “Invarianten beliebiger Differentialausdrücke,”
Nachr. d. König. Gesellsch. d. Wiss. zu Göttingen, Math-phys.
Klasse (1918): 37-44; Nina Byers, “E. Noether’s Discovery of the Deep Connection between Symmetries and Conservation Laws,”
Israel Mathematical Conference Proceedings
12 (1999),
http://www.physics.ucla.edu/~cwp/articles/noether.asg/noether.html
(accessed July 1, 2006). This contains links to Noether’s original paper including an English translation.

²⁷
Walter Truett Anderson,
The Truth about the Truth
(New York: Jeremy P. Tarcher/Putnam, 1996).

²⁸
Bede Rundle,
Why There Is Something Rather Than Nothing
(Oxford: Clarendon Press, 2004).

²⁹
Frank Wilczek, “The Cosmic Asymmetry between Matter and Antimatter,”
Scientific American
243, no. 6 (1980): 82-90.

³⁰
Stenger,
The Comprehensible Cosmos,
supplement H.

There can be no demonstrative argument to prove that those instances in which we have no experience, resemble those of which we have had experience.

—David Hume

The Privileged Planet

H
uman life is very sensitive to the physical conditions on Earth. If the atmosphere were not transparent to light in the so-called visible region of the electromagnetic spectrum, and if the sun did not provide light in that region, then our eyes would not be of any use. But, does this mean that the sun and Earth were specifically designed with those properties because human eyes are sensitive to the visible spectrum of light? As silly as that suggestion sounds, we hear similar arguments today presented as evidence for intelligent design in the universe. Of course the arguments are not presented in exactly that fashion but coated in a veneer of scientific-sounding language. But when that thin veneer is ripped away we are left with the even thinner substance underneath.

In his 1995 book,
The Creator and the Cosmos,
physicist Hugh Ross listed thirty-three characteristics a planet must have to support life. He also estimated the probability that such a combination be found in the universe as “much less than one in a million trillion
¹
.” He concluded that only “divine design” could account for human life.

However, Ross presented no estimate of the probability for divine design. Perhaps it is even lower! Ross and others who attempt to prove the existence of God on the basis of probabilities make a fundamental logical error. When using probabilities to decide between two or more possibilities, you must have a number for each possibility in order to compare. In this vast universe, highly unlikely events happen every day.

In a 2004 book called
The Privileged Planet,
astronomer Guillermo Gonzalez and theologian Jay Richards have carried the notion further, asserting that our place in the cosmos is not only special but also designed for discovery. They contend that conditions on Earth, particularly those that make human life possible, are also optimized for scientific investigation and that this constitutes “a signal revealing a universe so skillfully created for life and discovery that it seems to whisper of an extraterrestrial intelligence immeasurably more vast, more ancient, and more magnificent than anything we’ve been willing to expect or imagine
²
.” Oh, come on, guys, you are willing to imagine who that intelligence is.

Following this line of reasoning, the atmosphere of Earth is not only transparent in the visible spectral band so that humans can see with their eyes, but it also is designed in this way so that astronomers can build telescopes and thereby observe the fruits of divine creation in the heavens.

Have you ever wondered why the angular diameters of the moon and sun as viewed from Earth are almost exactly the same, though the two celestial objects differ greatly in size and distance from Earth? Without that coincidence, we would never experience the type of total eclipse of the sun in which we can actually view starlight near the edge of the sun’s disk.

Gonzalez and Richards marvel at the fact that we happen to live on a planet where total solar eclipses are observable, and present this as an example of design for discovery. As we saw in chapter 4, in 585
BCE
Thales of Miletus predicted a total eclipse that supposedly ended a war. In more recent times, observations made during total eclipses have been used to verify Einstein’s theory of general relativity, specifically the bending of starlight near the sun’s edge.

Gonzalez and Richards seem to think general relativity would not have been discovered (assuming the theories of physics are “out there” to be discovered, a notion I disputed in the previous chapter) had we lived on a planet without the coincidence of angular diameters. That is very dubious, since many other tests of general relativity have been made that do not involve eclipses
³
.

The privileged planet argument is reminiscent of the proposal by eighteenth-century German philosopher Gottfried Wilhelm Leibniz (d. 1716) that we live “in the best of all possible worlds.”

Leibniz was one of the greatest thinkers of all time, the independent coinventor (with Newton) of calculus. But this particular notion was ridiculed by the French philosopher FrançoisMarie Arouet de Voltaire (d. 1778) in his short story “Candide.”

There, Dr. Pangloss, a thinly disguised Leibniz, proclaims:

It is demonstrable that things cannot be otherwise than as they are; for as all things have been created for some end, they must necessarily be created for the best end. Observe, for instance, the nose is formed for spectacles, therefore we wear spectacles.

The legs are visibly designed for stockings, accordingly we wear stockings. Stones were made to be hewn and to construct casties, therefore My Lord has a magnificent castle; for the greatest baron in the province ought to be the best lodged. Swine were intended to be eaten, therefore we eat pork all the year round:

and they, who assert that everything is right, do not express themselves correctly; they should say that everything is best
⁴
.

Gonzalez and Richards are senior fellows of the Center for Science and Culture
⁵
, the arm of the Seattle-based Discovery Institute that, as we saw earlier, is charged with the task of bringing science and culture into line with evangelical Christian teachings by driving “wedges” between materialistic science and the rest of society
⁶
.

The Privileged Planet
constitutes a new wedge, a form of intelligent design designed to split conventional astronomy and physics off from the mainstream of public awareness. In 2005 the Discovery Institute produced a slick film under the same title presenting the arguments from the book. As with intelligent design in biology, the sectarian motives of the book and film were kept well hidden. So, when the film was presented by the Discovery Institute to the Smithsonian Institution for a special showing at the National Museum of Natural History in Washington, DC, along with a $16,000 fee, unsuspecting Smithsonian officials initially approved despite a house rule against showing political or religious material. That approval implied Smithsonian cosponsorship, which generated considerable heat from the scientific community.

The Smithsonian quickly withdrew its cosponsorship, stating:

“We have determined that the content of the film is not consistent with the mission of the Smithsonian Institution’s scientific research
⁷
.” They allowed the film to be shown but turned down the payment.

How Common Is Life in the Universe?

Let us take a look at the scientific facts about life in the universe, hopefully unbiased by theological considerations. Unfortunately, we only have one data point—Earth. Life has yet to be found anywhere but on Earth. Over a hundred planets beyond our solar system have been identified, with more being found regularly. None, so far, are likely to be suitable for complex life as we know it and certainly not for human life. This failure may be simply a matter of inadequate detector technology. However, the very fact that the powerful instruments of modern science, which can peer inside nuclei and out to the edge of the visible universe, have yet to find life outside Earth is already strong testimony that the galactic space around Earth is not exactly teeming with life.

Perhaps life may someday be confirmed on Mars or elsewhere in the solar system, such as under the ice on Jupiter’s moon Europa or on Saturn’s moon Titan. But such life undoubtedly will be at best primitive. Certainly humans cannot live on Mars or in an ocean on Europa without extensive life support. In fact, we very probably cannot live on more than the tiniest fraction of the planets in the universe. Not only are earthlike planets likely to be very rare; so are sunlike stars.

One often hears that our sun is a “typical star.” This is wrong.

In fact, 95 percent of all stars are less massive than the sun. Stars much more massive than the sun have short lifetimes. If life is to be widespread in the universe, then it will have to exist under a far wider range of conditions than exist on Earth. And, how likely then is the possibility of intelligent life?

The observations mentioned above imply that on the order of ten billion stars in the Milky Way may have planetary systems.

While some form of life might have evolved in a large fraction of these systems, the very reasons that Gonzalez and Richards give for Earth being “privileged” make it very unlikely that humans could survive without extensive life support, even on those planets that might otherwise be suitable for some kind of life.

In recent years a new scientific discipline called
astrobiology
has appeared on the scene to study the possibilities of extraterrestrial life. This has brought together not only astronomers and biologists but philosophers and theologians to debate such issues as the definition of life and the impact the discovery of life elsewhere would have on human thinking.

Sufficient data to settle the question of life elsewhere are still lacking. As mentioned, a whole spectrum of views can be found among those working in this field. At one extreme we have what is called the
rare-earth position,
as exemplified by the book of that title by paleontologist Peter D. Ward and astronomer Donald Brownlee, published in 2000
⁸
, and
The Privileged Planet,
which was discussed above. In this view, complex forms of life are uncommon if not exceedingly rare in the universe.

The other end of the spectrum maintains the viewpoint that complex life could in fact be quite common. Astronomer David Darling summarized both positions in
Life Everywhere,
which appeared in 2001
⁹
. He argues that the rare-earth position is far too conservative, given what we currently know and don’t know.

Both extremes and those in between agree that simple, primitive forms of life are likely to exist on an appreciable fraction of other planets. This conclusion is warranted by the discovery in recent years of new (but still DNA-based) forms of life on Earth, thriving under the most extreme conditions in deep-ocean vents, bubbling volcanic mud pots, frigid waters, and complete darkness.

Indeed, life on Earth may have even begun under those conditions.

The real controversy is over the likelihood of complex, multicellular life. While microbial life is found over a wide range of conditions on Earth, the complex structures that make up animals and plants are very sensitive to their environments. Since we are hardly going to settle the issue here, let us just look at the flavor of the debate.

Essentially, rare-earth supporters argue that the evolution of complex life requires a planet with many of the specific features of Earth that are expected to be exceedingly uncommon. These features include a highly circular orbit around a stable, sunlike star with a relatively high “metallicity,” that is, containing a significant fraction of chemical elements heavier than helium (a rather misleading term, since that includes everything but hydrogen and helium, not just metals). Planets are made from heavier elements, as are living organisms.

In the rare-earth view, in order to have complex life a planet must be orbited by a large, nearby moon that acts to stabilize the planet’s axis of rotation. The planetary system must orbit a single star and include giant planets to stabilize the life-planet’s orbit and shield it from comets and asteroids. The giant planets must also have highly circular orbits, or else they would have a destabilizing effect. Furthermore, the planetary system must be in a “habitable zone” of the galaxy, where metallicity is high, radiation is low, and chances of near encounters with other stars are low. It is also argued that the life-planet itself must have a mod-erate but not too high level and proper timing of catastrophic events, such as comet impacts and ongoing plate tectonics.

Not all galaxies have properties that are conducive to earthlike life. Globular clusters, small galaxies, and elliptical galaxies are metal poor. Not every galaxy in the universe may have planets and the other conditions necessary for life.

The rare-earth position is that essentially
all
of the special features of Earth are required for complex life, while essentially
none
of the known planets besides Earth, inside or outside of the solar system, meet these requirements.

Darling counters by referring to various studies that call into question each of the rare-earth claims
¹⁰
. The need for a large moon to stabilize the planet’s axis is debatable, as is the requirement that the axis be highly stable. The observations of extrasolar planets have so far been biased in favor of those with giant planets in elliptical orbits because these are the easiest to detect. Most of the planets that have been found so far orbit stars with metallicity comparable to the sun, but a few planets orbit stars with low metallicity, so this issue is complicated. And, as for the galactic habitable zone, Darling claims that the data are insufficient to draw any definitive conclusions. His position is not that complex: life is highly likely to be common, but rather that we lack the knowledge to definitively conclude that it is likely to be uncommon.