ons。 The dish runs away with the spoon。 In the Thomas the Tank Engine series； we even have anthropomorphic lootives and railway cars； charmingly portrayed。 No matter what we're thinking about； animate or inanimate； we tend to invest it with human traits。 We can't help ourselves。 The images e readily to mind。 Children are clearly fond of them。
When we talk about a 〃threatening〃 sky； a 〃troubled〃 sea diamonds 〃resisting〃 being scratched； the Earth 〃attracting〃 passing asteroid； or an atom being 〃excited；〃 we are again drawn to a kind of animist worldview。 We reify。 Some ancient level of our thinking endows inanimate Nature with life； passions； and forethought。
The notion that the Earth is self…aware has lately been growing at the fringes of the 〃Gaia〃 hypothesis。 But this was monplace belief of both the ancient Greeks and the earl Christians。 Origen wondered whether 〃the earth also； according to its own nature； is accountable for some sin。〃 A host of ancient scholars thought the stars alive。 This was also the position of Origen； of St。 Ambrose （the mentor of St。 Augustine）； and even； in a more qualified form； of St。 Thomas Aquinas。 The Stoic philosophical position on the Sun's nature was stated by Cicero； in the first century B。C。： 〃Since the Sun resembles those fires which are contained in the bodies of living creatures； the Sun must also be alive。〃
Animist attitudes in general seem to have been spreading recently。 In a 1954 American survey； 75 percent of people polled were willing to state that the Sun is not alive； in 1989； only 30 percent would support so rash a proposition。 On whether an automobile tire can feel anything； 90 percent of respondents denied it emotions in 1954； but only 73 percent in 1989。
We can recognize here a shorting—in some circumstances serious—in our ability to understand the world。 Characteristically； willy…nilly； we seem pelled to project our own nature onto Nature。 Although this may result in a consistently distorted view of the world； it does have one great virtue—projection is the essential precondition for passion。
Okay； maybe we're not much； maybe we're humiliatingly related t0 apes； but at least we're the best there is。 God and angels aside； we're the only intelligent beings in the Universe。 One correspondent writes to me； 〃I am as sure of this as anything in my experience。 There is no conscious life anywhere else in the Universe。 Mankind thus returns to its rightful position as center of the universe。〃 However； partly through the influence of science acid science fiction； most people today； in the United States at least； reject this proposition—for reasons essentially stated by the ancient Greek philosopher Chrysippus： 〃For any human being in existence to think that there is nothing in the whole world superior to himself would be an insane piece of arrogance。〃
But the simple fact is that we have not yet found extraterrestrial life。 We are in the earliest stages of looking。 The question is wide open。 If I had to guess—especially considering our long sequence of failed I would guess that the Universe is filled with beings far more intelligent； tar more advanced than we are。 But of course I might be wrong。 Such a conclusion is at best based on a plausibility argument； derived from the numbers of planets； the ubiquity of organic matter； the immense timescales available for evolution； and so on。 It is not a scientific demonstration。 The question is among the most fascinating in all of science。 As described in this book； we are just developing the tools to treat it seriously。
What about the related matter of whether we are capable of creating intelligences smarter than ourselves？ puters routinely do mathematics that no unaided human can manage； outperform world champions in checkers and grand masters in chess； speak and understand English and other languages； write presentable short stories and musical positions； learn from their mistakes； and petently pilot ships； airplanes； and spacecraft。 Their abilities steadily improve。 They're getting smaller； faster； and cheaper。 Each year； the tide of scientific advance laps a little further ashore on the island of human intellectual uniqueness with its embattled castaways。 If； at so early a stage in our technological evolution； we have been able to go so far in creating intelligence out of silicon and metal； what will be possible in the following decades and centuries？ What happens when smart machines are able to manufacture smarter machines？
PERHAPS THE CLEAREST INDICATION that the search for an unmerited privileged position for humans will never be wholly abandoned is what in physics and astronomy is called the Anthropic Principle。 It would be better named the Anthropocentric Principle。 It es in various forms。 The 〃Weak〃 Anthropic Principle merely notes that if the laws of Nature and the physical constants—such as the speed of light； the electrical charge of the electron； the Newtonian gravitational constant； or Planck's quantum mechanical constant had been different； the course of events leading to the origin of humans would never have transpired。 Under other laws and constants； atoms would not hold together； stars would evolve too quickly to leave sufficient time for life to evolve on nearby planets； the chemical elements of which life is made would never have been generated； and so on。 Different laws； no humans。
There is no controversy about the Weak Anthropic Principle： Change the laws and constants of Nature； if you could； and a very different universe may emerge—in many cases； a universe inpatible with life。* The mere fact that we exist implies （but does not impose） constraints on the laws of Nature。 In contrast； the various 〃Strong〃 Anthropic Principles go much farther； some of their advocates e close to deducing that the laws of Nature and the values of the physical constants were established （don't ask how or by Whom） so that humans would eventually e to be。 Almost all of the other possible universes； they say； are inhospitable。 In this way； the ancient conceit that the Universe was made for us is resuscitated。
* Our universe is almost inpatible with life—or at least what we understand as necessary for life： Even if every star in a hundred billion galaxies had an Earthlike planet； without heroic technological measures life could prosper in only about 10…37 the volume of the Universe。 For clarity； let's write it out： only 0。000 000 000 000 000 000 000 000 000 000 000 000 1 of our universe is hospitable to life。 Thirty…six zeroes before the one。 The rest is cold； radiation…riddled black vacuum。
To me it echoes Dr。 Pangloss in Voltaire's Candide； convinced that this world； with all its imperfections； is the best possible。 It sounds like playing my first hand of bridge； winning； knowing that there are 54 billion billion billion （5。4 X 1028） possible other hands that I was equally likely to have been dealt 。 。 。 and then foolishly concluding that a god of bridge exists and favors me； a god who arranged the cards and the shuffle with my victory foreordained from The Beginning。 We do not know how many other winning hands there are in the cosmic deck； how many other kinds of universes； laws of Nature； and physical constants： that could also lead to life and Intelligence and perhaps even delusions of self…importance。 Since we know next to nothing about how the Universe was made—or even if it was made—it's difficult to pursue these notions productively。
Voltaire asked 〃Why is there anything？〃 Einstein's formulation was to ask whether God had any choice in creating the Universe。 But if the Universe is infinitely old—if the Big Bang some 15 billion years ago is only the most recent cusp in an infinite series of cosmic contractions and expansions—then it was never created and the question of why it is as it is is rendered meaningless。
If； on the other hand； the Universe has a finite age； why is it the way it is？ Why wasn't it given a very different character？ Which laws of Nature go with which others？ Are there meta…laws specifying the connections？ Can we possibly discover them？ Of all conceivable laws of gravity； say； which ones can exist simultaneously with which conceivable laws of quantum physics that determine the very existence of macroscopic matter？ Are all laws we can think of possible； or is there only a restricted number that can somehow be brought into existence？ Clearly we have not a glimmering of how to determine which laws of Nature are 〃possible〃 and which are not。 Nor do we have more than the most rudimentary notion of what correlations of natural laws are 〃permitted。〃
For example； Newton's universal law of gravitation specifies that the mutual gravitational force attracting two bodies towards each other is inversely proportional to the square of how far they are apart。 You move twice as far from the center of the Earth and you weigh a quarter as much； ten times farther and you weigh only a hundredth of your ordinary weight； etc。 It is this inverse square law that permits the exquisite circular and elliptical orbits of planets around the Sun； and moons around the planets—as well as the precision trajectories of our interplanetary spacecraft。 If r is the distance between the centers of two masses；