Human beings climb. Always have, always will. First hills, then mountains, then pinnacles so high they're called "death zones." That's as high as legs could carry them, but not high enough. So people invented balloons, blimps, airplanes, and spacecraft, the higher the better—to a point.
At first, scaling heights made people feel big and powerful. Then they began to feel small, utterly insignificant even, in the hugeness of the cosmos. Today, ironically, the same forces that once shrank humanity's perception of himself now magnify him beyond the wildest imagination, yet with no basis for pride and every reason for humility. Those forces, insatiable curiosity, and capacity for inquiry have lifted humans to a vista, an insight called the anthropic principle, that carries their gaze to the edge of the universe and beyond.
The anthropic principle says that the universe appears "designed" for the sake of human life. More than a century of astronomy and physics research yields this unexpected observation: the emergence of humans and human civilization requires physical constants, laws, and properties that fall within certain narrow ranges—and this truth applies not only to the cosmos as a whole but also to the galaxy, planetary system, and planet humans occupy. To state the principle more dramatically, a preponderance of physical evidence points to humanity as the central theme of the cosmos.
Support for the anthropic principle comes from an unwavering and unmistakable trend line within the data: the more astronomers learn about the universe and the requirements of human existence, the more severe the limitations they find governing the structure and development of the universe to accommodate those requirements. In other words, additional discoveries are leading to more indicators of large-scale and small-scale fine-tuning.
In 1961, astronomers acknowledged just two characteristics of the universe as "fine-tuned" to make physical life possible.1 The more obvious one was the ratio of the gravitational force constant to the electromagnetic force constant. It cannot differ from its value by any more than one part in 1040 (one part in ten thousand trillion trillion trillion) without eliminating the possibility for life. Today, the number of known cosmic characteristics recognized as fine-tuned for life—any conceivable kind of physical life—stands at thirty-eight.2 Of these, the most sensitive is the space energy density (the self-stretching property of the universe). Its value cannot vary by more than one part in 10120 and still allow for the kinds of stars and planets physical life requires.3
Evidence of specific preparation for human existence shows up in the characteristics of the solar system, as well. In the early 1960s astronomers could identify just a few solar system characteristics that required fine-tuning for human life to be possible. By the end of 2001, astronomers had identified more than 150 finely-tuned characteristics.4 In the 1960s the odds that any given planet in the universe would possess the necessary conditions to support intelligent physical life were shown to be less than one in ten thousand.5 In 2001 those odds shrank to less than one in a number so large it might as well be infinity (10173).6
An account of scientific evidence in support of the anthropic principle fills several books.7 The authors' religious beliefs run the gamut from agnosticism to deism to theism, but virtually every research astronomer alive today agrees that the universe manifests exquisite fine-tuning for life.8
The Revolt Against a Revolution
This view of humanity as the focal point of the cosmos represents the historic overthrow of an idea rooted in an ancient revolution, the Copernican revolution. For the first fifteen centuries of the Christian era, Western science assumed that Earth's inhabitants, humans in particular, occupied the central position in the universe. When Nicolaus Copernicus revived the ancient Greek proof that the Sun, rather than Earth, holds the central position in Earth's system of planets, a new scientific perspective took root.9 From this perspective, the Copernican principle, emerged the philosophical notion that humans occupy no privileged or exceptional position in the universe. For the past four hundred years, this principle has been the reigning paradigm of science and society. And, during the past forty years, an extension of it, the mediocrity principle, has grown increasingly prevalent. The mediocrity principle asserts that humanity is not special in any way and that human origin and development have likely been duplicated on billions of other sites throughout the cosmos.
The anthropic principle, emerging almost simultaneously with the mediocrity principle, emphatically contradicts it, exposing a distortion of Copernican thinking. The anthropic principle makes this obvious and crucial distinction: while humanity's place in the universe is not spatially central, it does not necessarily follow that humanity's place is not central, or special, in any way.
Few people yet realize that current cosmological research demonstrates a physical universe with no spatial center. All the matter and energy of the universe reside on the three-dimensional surface of the expanding four-dimensional universe. Just as all Earth's cities reside on the planet's two-dimensional surface and none can be identified as geographically central to all others, likewise none of the galaxies, stars, and planets hold the center position on the cosmic 3-D surface.
In one sense, the anthropic principle is possible because Copernicus was right. What makes humanity's location in the cosmos unique, or special, is that Earth resides away from the center of any astronomical system, such as Earth's galaxy. Humanity lives in a unique location—and moment—in cosmic space-time that allows not only for the possibility of human existence but also for the opportunity to discover that human existence represents a miracle, a special case.
Earth's particular location gives humans a special window to the solar system, the Milky Way galaxy, and the universe itself. In virtually any other galaxy or at any other location in Earth's galaxy and at every other time in cosmic history, the view to the surrounding area would be so unstable and/or so occluded that the form, structure, size, and other characteristics of the galaxy and universe would remain obscure to any sentient observers.10 Earth's creatures enjoy a special view to the splendors of the cosmos. Nowhere else and at no other time in the universe would such glory be visible.11
The importance of the anthropic principle can hardly be overstated. It returns legitimacy and respectability to the human species as a worthy, even primary, subject of scientific research. Further, the anthropic principle has the potential to bring about a paradigm shift arguably as profound as any shift in human remembrance.
As early as the 1980s, physicist Paul Davies concluded that the physical evidence for design of the universe and of Earth for human life could rightly be described as overwhelming.12 Today, no physicist or astronomer who has researched the question denies that the universe, the Milky Way galaxy, and the solar system possess compelling hallmarks of intentional design for human life. Many researchers have commented over the past twenty years that it seems the universe "knew" humans were coming.
Brandon Carter, the British mathematician who coined the term "anthropic principle" (1974),13 noted the strange inequity of a universe that spends about 15 billion years "preparing" for the existence of a creature that has the potential to survive no more than 10 million years (optimistically).14 Carter formalized this enormous imbalance between the time required to produce the possibility for human life and the brevity of the species' (potential) survival as the "anthropic principle inequality."15
In response, some researchers speculated that the human species might represent an anomaly, an exception to the rule (e.g., a late bloomer or a more fragile species) among many possible intelligent life forms elsewhere in the cosmos. However, Carter and (later) astrophysicists John Barrow and Frank Tipler demonstrated that the inequality exists for virtually any conceivable intelligent species under any conceivable life-support conditions.16 Roughly 15 billion years represents a minimum preparation time for advanced life: 11 billion toward formation of a stable planetary system, one with the right chemical and physical conditions for primitive life, and four billion more years toward preparation of a planet within that system, one richly layered with the biodeposits necessary for civilized intelligent life. Even this long time and convergence of "just right" conditions reflect miraculous efficiency.
Moreover the physical and biological conditions necessary to support an intelligent civilized species do not last indefinitely. They are subject to continuous change: the Sun continues to brighten, Earth's rotation period lengthens, Earth's plate tectonic activity declines, and Earth's atmospheric composition varies. In just 10 million years or less, Earth will lose its ability to sustain human life. In fact, this estimate of the human habitability time window may be grossly optimistic. In all likelihood, a nearby supernova eruption, a climatic perturbation, a social or environmental upheaval, or the genetic accumulation of negative mutations will doom the species to extinction sometime sooner than twenty thousand years from now.17
These figures demonstrate that the inequality is extreme. The survival time for advanced intelligent physical life is only a millionth as long as the time required to produce the conditions necessary for its survival.
Another British mathematical physicist, Roger Penrose, was among the first to give voice to a philosophical conclusion: the extremely high level of fine-tuning astronomers and physicists discern powerfully suggests a purpose behind the universe.18 That the design is so focused on providing a home for humanity implies that a significant, even central, part of the purpose for the universe is anthropic. Specifically, the universe was created for the express benefit of humanity.
Given the awesome capacities necessary to create and design the universe, the purpose for humanity must be significant indeed. Further, given that human survivability is cosmically brief means that humanity's purpose can and must be fulfilled quickly. The rapid fulfillment of a profoundly significant purpose for humanity—that's the message of the Bible. No other "revelation" makes such perfect sense of everything humanity observes and experiences.
Purpose, Destiny, and Hope
Distinguished astrophysicists Lawrence Krauss and Glenn Starkman recently analyzed the ultimate consequences of the measured self-stretching property of the universe.19 They deduced that the universe from now on will expand at a faster and faster rate. This exponentially increasing cosmic expansion means that astronomers will see less and less of the universe as time goes on. Thus, knowledge of the universe will decrease with time. Eventually, the cosmic expansion will be so rapid that intelligent beings will lose the capacity to draw adequate energy for work from the heat flow of the universe. All forms of knowledge, then, will necessarily decrease. Inevitably, heat flow will be so tiny that all metabolic reactions will cease, and with their ceasing, all possibility for physical life will end. "Consciousness is eventually lost."20
Krauss and Starkman's response—an expression of despair—betrays their presumption that humanity's destiny must lie within this universe. An important aspect of the biblical message is that God has an existence and a plan for humanity beyond the confines of the cosmos. His plan involves the cosmos but does not end there. Throughout the Old and New Testaments, God reveals His plan to prepare those humans for a paradise vastly superior to anything Earth can offer, a new creation completely beyond the physics and dimensions of the universe.
Therefore, the biblical basis for purpose, destiny, and hope supersedes the limitations, even predicts the limitations and cessation, of the universe. The anthropic principle becomes personal, however, with the commonsense observation that human beings universally and uniquely yearn for a sense of destiny and purpose. Human beings stay alive not just by the powerful instinct to survive possessed by all living creatures, but by a unique and universal awareness that they exist for a reason beyond mere physical survival.
The Christ Connection
Those people who need hard data to affirm their sense of destiny can find it. The space-time theorems of general relativity prove that an Entity transcending matter, energy, space, and time is the cause of the universe in which humanity lives.21 Of all the gods, forces, or principles that people have proposed throughout human history to explain the existence and operation of the universe, only the God of the Bible is consistent with the characteristics of the cause established in these space-time theorems.22 Only the Bible predicts and explains the anthropic principle.
True to their inquisitive and skeptical nature, some scientists and philosophers have challenged the validity of the anthropic principle and certainly of its implications for the Christian worldview and faith. Stephen Hawking and Carl Sagan argued that the design of such a vast cosmos for such an infinitesimal creature seems wasteful, thus inconsistent with the character of the Christian's all-wise, all-powerful God.23 Such a God, they imply, would have fulfilled His purpose of providing humanity a home by creating just one planet in one planetary system in a relatively tiny and short-lived cosmos.
This argument fails to consider, however, that purpose governs what a person (or God) does as opposed to what he can do. Given the physics of the universe, the laws and properties for which the Bible reveals a specific divine purpose (see "The Physics of Sin," page 00), the universe is the necessary size and age. A universe either slightly less massive or more massive than what researchers observe would be unsuitable for human life.24 In a human frame of reference, God's provision of such an enormous universe so carefully "machined" for billions of years for human benefit makes a compelling statement about His care for humanity—and His purposefulness.
Some skeptics have attempted to trivialize the anthropic principle with the assertion that humans simply would not be here to observe the universe unless the extremely unlikely did somehow happen to take place. British philosopher Richard Swinburne responded to this notion with a simple illustration.25 He points out that the survivor of a firing squad execution would not attribute his or her survival to a lucky accident. Rather, the survivor would conclude that either the rifles were loaded with blanks or that each of the executioners missed on purpose. The measured fine-tuning of the universe tells us that Someone purposed for humans to exist for a certain period of time.
Another argument claims that there is nothing remarkable about the fine-tuning of the universe if an infinitude of universes exist, each with a different set of characteristics. In this case, chance could dictate that at least one would manifest the characteristics necessary for human life.
The fallacy in this appeal represents a form of the gambler's fallacy. A gambler might conclude that an ordinary coin could land on heads a hundred thousand consecutive times if he rationalizes that 2100,000 coins exist (though he cannot see them), each being flipped 100,000 times by 2100,000 coin flippers. Statistically, one of these coins could come up heads 100,000 times. Such thinking is considered fallacious, however, because the gambler has no evidence for the existence of the other coins, coin flippers, or distinct results. With a sample size of one, the only rational conclusion to draw is that someone "fixed" the coin to land on heads. In the case of the universe, no evidence can be found for the existence of other universes. In fact, the principles of relativity dictate that the space-time envelope of a universe that contains observers can never overlap that of any other universe(s). Thus, the sample size for human observers is one and always will be one, and the conclusion that Someone purposed, or fixed, the universe for human existence remains compelling.
Testing the Conclusion
The anthropic principle invites testing. A skeptic not yet persuaded that the fine-tuning of the universe reflects more than a lucky coin toss can choose to examine the universe, the "coin," more closely. If the anthropic principle and its implications for transcendent design are false, research will discover declining evidence for fine-tuning and existing evidence will be erased by new data. If, on the other hand, the anthropic principle and its implications are true, research will yield an increase in both the number of fine-tuned characteristics and the degree of fine-tuning. Based on the accumulating evidence, to bet on the anthropic principle seems safer than taking another breath. The anthropic principle energizes humanity's climb on the pinnacles of Truth.