In a passage reminiscent of Plus IX, Appleyard even decries the fact that "a modern democracy can be expected to include a number of contradictory religious faiths which are obliged to agree on a certain limited number of general injunctions, but no more. They must not burn each other's places of worship, but they may deny, even abuse each other's God. This is the effective, scientific way of proceeding."
But what is the alternative? Obdurately to pretend to certainty in an uncertain world? To adopt a comforting belief system, no matter how out of kilter with the facts it is? If we don't know what's real, how can we deal with reality? For practical reasons, we cannot live too much in fantasyland. Shall we censor one another's religions and burn down one another's places of worship? How can we be sure which of the thousands of human belief systems should become unchallenged, ubiquitous, mandatory?
These quotations betray a failure of nerve before the Universe its grandeur and magnificence, but especially its indifference. Science has taught us that, because we have a talent for deceiving ourselves, subjectivity may not freely reign. This is one reason Appleyard so mistrusts science: It seems too reasoned, measured, and impersonal. Its conclusions derive from the interrogation of Nature, and are not in all cases predesigned to satisfy our wants. Appleyard deplores moderation. He yearns for inerrant doctrine, release from the exercise of judgment, and an obligation to believe but not to question. He has not grasped human fallibility. He recognizes no need to institutionalize error-correcting machinery either in our social institutions or in our view of the Universe.
This is the anguished cry of the infant when the Parent does not come. But most people eventually come to grips with reality, and with the painful absence of parents who will absolutely guarantee that no harm befalls the little ones so long as they do what they are told. Eventually most people find ways to accommodate to the Universe—especially when given the tools to think straight.
"All that we pass on to our children" in the scientific age, Appleyard complains, "is the conviction that nothing is true, final or enduring, including the culture from which they sprang." How right he is about the inadequacy of our legacy. But would it be enriched by adding baseless certainties? He scorns "the pious hope that science and religion are independent realms which can easily be separated." Instead, "science, as it is now, is absolutely not compatible with religion."
But isn't Appleyard really saying that some religions now find it difficult to make unchallenged pronouncements on the nature of the world that are straight-out false? We recognize that even revered religious leaders, the products of their time as we are of ours, may have made mistakes. Religions contradict one another on small matters, such as whether we should put on a hat or take one off on entering a house of worship, or whether we should eat beef and eschew pork or the other way around, all the way to the most central issues, such as whether there are no gods, one God, or many gods.
Science has brought many of us to that state in which Nathaniel Hawthorne found Herman Melville: "He can neither believe, nor be comfortable in his unbelief." Or Jean-Jacques Rousseau: "They had not persuaded me, but they had troubled me. Their arguments had shaken me without ever convincing me . . . It is hard to prevent oneself from believing what one so keenly desires." As the belief systems taught by the secular and religious authorities are undennined, respect for authority in general probably does erode. The lesson is clear: Even politics] leaders must be wary of embracing false doctrine. This is not a failing of science, but one of its graces.
Of course, worldview consensus is comforting, while clashes of opinion may be unsettling, and demand more of us. But unless we insist, against all evidence, that our ancestors were perfect, the advance of knowledge requires us to unravel and then restitch the consensus they established.
In some respects, science has far surpassed religion in delivering awe. How is it that hardly any major religion has looked at science and concluded, "This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant. God must be even greater than we dreamed"? Instead they say, "No, no, no! My god is a little god, and I want him to stay that way." A religion, old or new, that stressed the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths. Sooner or later, such a religion will emerge.
IF YOU LIVED two or three millennia ago, there was no shame in holding that the Universe was made for us. It was an appealing thesis consistent with everything we knew; it was what the most learned among us taught without qualification. But we have found out much since then. Defending such a position today amounts to willful disregard of the evidence, and a flight from self-knowledge.
Still, for many of us, these deprovincializations rankle. Even if they do not fully cant' the day, they erode confidence—unlike the happy anthropocentric certitudes, rippling with social utility, of an earlier age. We long to be here for a purpose, even though, despite much self-deception, none is evident. "The meaningless absurdity of life," wrote Leo Tolstoy, "is the only incontestable knowledge accessible to man." Our time is burdened under the cumulative weight of successive debunkings of our conceits: We're Johnny-come-latelies. We live in the cosmic boondocks. We emerged from microbes and muck. Apes are our cousins. Our thoughts and feelings are not fully under our own control. There may be much smarter and very different beings elsewhere. And on top of all this, we're making a mess of our planet and becoming a danger to ourselves.
The trapdoor beneath our feet swings open. We find ourselves in bottomless free fall. We are lost in a great darkness, and there's no one to send out a search party. Given so harsh a reality, of course we're tempted to shut our eyes and pretend that we're safe and snug at home, that the fall is only a bad dream.
We lack consensus about our place in the Universe. There is no generally agreed upon long-term vision of the goal of our species—other than, perhaps, simple survival. Especially when times are hard, we become desperate for encouragement, unreceptive to the litany of great demotions and dashed hopes, and much more willing to hear that we're special, never mind if the evidence is paper-thin. If it takes a little myth and ritual to get us through a night that seems endless, who among us cannot sympathize and understand?
But if our objective is deep knowledge rather than shallow reassurance, the gains from this new perspective far outweigh the losses. Once we overcome our fear of being tiny, we find ourselves on the threshold of a vast and awesome Universe that utterly dwarfs—in time, in space, and in potential—the tidy anthropocentric proscenium of our ancestors. We gaze across billions of light-years of space to view the Universe shortly after the Big Bang, and plumb the fine structure of matter. We peer down into the core of our planet, and the blazing interior of our star. We read the genetic language in which is written the diverse skills and propensities of every being on Earth. We uncover hidden chapters in the record of our own origins, and with some anguish better understand our nature and prospects. We invent and refine agriculture, without which almost all of us would starve to death. We create medicines and vaccines that save the lives of billions. We communicate at the speed of light, and whip around the Earth in an hour and a half. We have sent dozens of ships to more than seventy worlds, and four spacecraft to the stars. We are right to rejoice in our accomplishments, to be proud that our species has been able to see so far, and to judge our merit in part by the very science that has so deflated our pretensions.
To our ancestors there was much in Nature to be afraid of—lightning, storms, earthquakes, volcanos, plagues, drought, long winters. Religions arose in part as attempts to propitiate and control, if not much to understand, the disorderly aspect of Nature. The scientific revolution permitted us to glimpse an underlying ordered Universe in which there was a literal harmony of the worlds (Johannes Kepler's phrase). If we understand Nature, there is a prospect of controlling it or at least mitigating the harm it may bring. In this sense, sc
ience brought hope.
Most of the great deprovincializing debates were entered into with no thought for their practical implications. Passionate and curious humans wished to understand their actual circumstances, how unique or pedestrian they and their world are, their ultimate origins and destinies, how the Universe works. Surprisingly, some of these debates have yielded the most profound practical benefits. The very method of mathematical reasoning that Isaac Newton introduced to explain the motion of the planets around the Sun has led to most of the technology Of our modern world. The Industrial Revolution, for all its shortcomings, is still the global model of how an agricultural nation can emerge from poverty. These debates have bread-and-butter consequences.
It might have been otherwise. It might have been that the balance lay elsewhere, that humans by and large did not want to yaw about a disquieting Universe, that we were unwilling to hermit challenges to the prevailing wisdom. Despite determined resistance in every age, it is very much to our credit that we have allowed ourselves to follow the evidence, to draw conclusions that at first seem daunting: a Universe so much larger and older that our personal and historical experience is dwarfed and humbled, a Universe in which, every day, suns are born and worlds obliterated, a Universe in which humanity, newly arrived, clings to an obscure clod of matter.
How much more satisfying had we been placed in a garden custom-made for us, its other occupants put there for us to use as we saw fit. There is a celebrated story in the Western tradition like this, except that not quite everything was there for us. There was one particular tree of which we were not to partake, a tree of knowledge. Knowledge and understanding and wisdom were forbidden to us in this story. We were to be kept ignorant. But we couldn't help ourselves. We were starving for knowledge—created hungry, you might say. This was the origin of all our troubles. In particular, it is why we no longer live in a garden: We found out too much. So long as we were incurious and obedient, I imagine, we could console ourselves with our importance and centrality, and tell ourselves that we were the reason the Universe was made. As we began to indulge our curiosity, though, to explore, to learn how the Universe really is, we expelled ourselves from Eden. Angels with a flaming sword were set as sentries at the gates of Paradise to bar our return. The gardeners became exiles and wanderers. Occasionally we mourn that lost world, but that, it seems to me, is maudlin and sentimental. We could not happily have remained ignorant forever.
There is in this Universe much of what seems to he design. Every time we come upon it, we breathe a sigh of relief. We are forever hoping to find, or at least safely deduce, a Designer. But instead, we repeatedly discover that natural processes—collisional selection of worlds, say, or natural selection of gene pools, or even the convection pattern in a pot of boiling water—can extract order out of chaos, and deceive us into deducing purpose where there is none. In everyday life, we often sense—in the bedrooms of teenagers, or in national politics—that chaos is natural, and order imposed from above. While there are deeper regularities in the Universe than the simple circumstances we generally describe as orderly, all that order, simple and complex, seems to derive from laws of Nature established at the Big Bang (or earlier), rather than as a consequence of belated intervention by an imperfect deity. "God is to be found in the details" is the famous dictum of the German scholar Abu Warburg. But, amid much elegance and precision, the details of life and the Universe also exhibit haphazard, jury-rigged arrangements and much poor planning. What shall we make of this: an edifice abandoned early in construction by the architect?
The evidence, so far at least and laws of Nature aside, does not require a Designer. Maybe there is one hiding, maddeningly unwilling to be revealed. Sometimes it seems a very slender hope.
The significance of our lives and our fragile planet is then determined only by our own wisdom and courage. We are the custodians of life's meaning. We long for a Parent to care for us, to forgive us our errors, to save us from our childish mistakes. But knowledge is preferable to ignorance. Better by far to embrace the hard truth than a reassuring fable.
If we crave some cosmic purpose, then let us find ourselves a worthy goal.
CHAPTER 5: IS THERE INTELLIGENT LIFE ON EARTH?
They journeyed a long time and found nothing. At length they discerned
a small light, which was the Earth . . . [But] they could not find the
smallest reason to suspect that we and our fellow—citizens
of this globe have the honor to exist.
—VOLTAIRE, MICROMEGAS.
A PHILOSOPHICAL HISTORY (1752)
There are places, in and around our great cities, where the natural world has all but disappeared. You can make out streets and sidewalks, autos, parking garages, advertising billboards, monuments of glass and steel, but not a tree or a blade of grass or any animal—besides, of course, the humans. There are lots of humans. Only when you look straight up through the skyscraper canyons can you make out a star or a patch of blue—reminders of what was there long before humans came to be. But the bright lights of the big cities bleach out the stars, and even that patch of blue is sometimes gone, tinted brown by industrial technology.
It's not hard, going to work every day in such a place, to be impressed with ourselves. How we've transformed the Earth for our benefit and convenience! But a few hundred miles up or down there are no humans. Apart from a thin film of life at the very surface of the Earth, an occasional intrepid spacecraft, and some radio static, our impact on the Universe is nil. It knows nothing of us.
YOU'RE AN ALIEN EXPLORER entering the Solar System after a long journey through the blackness of interstellar space. You examine the planets of this humdrum star from afar—a pretty handful, some gray, some blue, some red, some yellow. You're interested in what kinds of worlds these are, whether their environments are static or changing, and especially whether there are life and intelligence. You have no prior knowledge of the Earth. You've just discovered its existence.
There's a galactic ethic, let's imagine: Look but don't touch. You can fly by these worlds; you can orbit them; but you are strictly forbidden to land. Under such constraints, could you figure out what the Earth's environment is like and whether anyone lives there?
As you approach, your first impression of the whole Earth is white clouds, white polar caps, brown continents, and some bluish substance that covers two thirds of the surface. When you take the temperature of this world from the infrared radiation it emits, you find that most latitudes are above the freezing point of water, while the polar caps are below freezing. Water is a very abundant material in the Universe; polar caps made of solid water would be a reasonable guess, as well as clouds of solid and liquid water.
You might also he tempted by the idea that the blue stuff is enormous quantities—kilometers deep—of liquid water. The suggestion is bizarre, though, at least as far as this solar system is concerned, because surface oceans of liquid water exist nowhere else. When you look in the visible and near-infrared spectrum for telltale signatures of chemical composition, sure enough you discover water ice in the polar caps, and enough water vapor in the air to account for the clouds; this is also just the right amount that must exist because of evaporation if the oceans are in fact made of liquid water. The bizarre hypothesis is confirmed.
The spectrometers further reveal that the air on this world is one fifth oxygen, O2. No other planet in the Solar System has anything close to so much oxygen. Where does it all come from? The intense ultraviolet light from the Sun breaks water, H20, down into oxygen and hydrogen, and hydrogen, the lightest gas, quickly escapes to space. This is a source of O2, certainly, but it doesn't easily account for so much oxygen.
Another possibility is that ordinary visible light, which the Sun pours out in vast amounts, is used on Earth to break water apart—except that there's no known way to do this without life. There would have to be plants, life-forms colored by a pigment that strongly absorbs visible light, that knows how to split a wate
r molecule by saving up the energy of two photons of light, that retains the H and excretes the O, and that uses the hydrogen thus liberated to synthesize organic molecules. The plants would have to be spread over much of the planet. All this is asking a lot. If you're a good skeptical scientist, so much Oz would not be proof of life. But it certainly might be cause for suspicion.
With all that oxygen you're not surprised to discover ozone (O3) in the atmosphere, because ultraviolet light makes ozone out of molecular oxygen (O2). The ozone then absorbs dangerous ultraviolet radiation. So if the oxygen is due to life, there's a curious sense in which the life is protecting itself. But this life "night be mere photosynthetic plants. A high level of intelligence is not implied.
When you examine the continents more closely, you find there are, crudely speaking, two kinds of regions. One shows the spectrum of ordinary rocks and minerals as found on many worlds. The other reveals something unusual: a material, covering vast areas, that strongly absorbs red light. (The Sun, of course, shines in light of all colors, with a peak in the yellow.) This pigment might be just the agent needed if ordinary visible light is being used to break water apart and account for the oxygen in the air. It's another hint, this time a little stronger, of life, not a bug here and there, but a planetary surface overflowing with life. The pigment is in fact chlorophyll: It absorbs blue light as well as red, and is responsible for the fact that plants are green. What you're seeing is a densely vegetated planet.
So the Earth is revealed to possess three properties unique at least in this solar system—oceans, oxygen, life. It's hard not to think they're related, the oceans being the sites of origin, and the oxygen the product, of abundant life.
When you look carefully at the infrared spectrum of the Earth, you discover the minor constituents of the air. In addition to water vapor, there's carbon dioxide (CO2), methane (CH4), and other gases that absorb the heat that the Earth tries to radiate away to space at night. These gases warm the planet. Without them, the Earth would everywhere be below the freezing point of water. You've discovered this world's greenhouse effect.