The Case for a Creator: In the Beginning
The Case for a Creator, Chapter 5
The second premise of the kalam cosmological argument is that the universe began to exist. In discussing this premise, William Lane Craig asks the question of whether the universe necessarily had a beginning or whether it could have existed for an infinite amount of time before now. He argues that the former is the only option:
"...if the past were really infinite, then that would mean we have managed to traverse an infinite past to arrive at today. It would be as if someone had managed to count down all of the negative numbers and to arrive at zero at the present moment. Such a task is intuitively nonsense" [p.104].
The fallacy here is in Craig's implicit claim that it's necessary to "traverse" the past to arrive at the present. This position assumes that time is like a moving light - a spotlight illuminating moments in succession, briefly making each one the present before moving on to the next. But this assumption is false. There is no moving light of time. As we know from modern physics, in particular the theories of special and general relativity, "past", "present" and "future" are not intrinsic properties of reality. Those terms are to time as words like "near" and "far" are to space - they do not uniquely single out a particular place or a particular moment, but can only be defined from the perspective of the observer. The moments themselves all exist eternally, and nothing needs to "traverse" them. It's the sequence of our memories, the so-called arrow of time, that seems to make them flow from one to the other.
"You see, the idea of an actual infinity is just conceptual; it exists only in our minds... it's not descriptive of what can happen in the real world." [p.103]
If this is true, then Craig has just dealt a critical blow to his own faith. According to Christian theology, God is omnipotent - able to create any of the infinity of logically possible worlds. But if an actual infinity cannot exist in the real world, then it must be the case that God is not omnipotent; the number of possible worlds he can create must be finite, which must mean there are possible worlds that God does not have the ability to bring about. This argument also rules out omniscience, for the same reason; out of the conceptual infinity of true propositions, there must be some that God does not know. Again, these contradictions do not seem to occur to Strobel the hard-charging journalist.
Craig next (finally!) turns to the science. He gives an accurate summary of the major lines of evidence for the Big Bang - the relationship of galactic redshift to distance, the cosmic microwave background radiation, and the abundance of light elements - and calls Big Bang theory "very securely established as a scientific fact" [p.107]. I won't quibble with this, although some of his fellow Christians would.
However, Craig does object to a common adjunct of the Big Bang theory, cosmic inflation, which holds that the universe underwent a period of ultra-rapid expansion in its first few microseconds. He gifts us with this absolute gem of a line:
"So even though most theorists accept inflation today, I'm rather suspicious of the whole thing, because it appears to be motivated by a philosophical bias." [p.107]
Because William Lane Craig, of course, is entirely innocent of such biases.
Cosmological inflation was proposed to solve two problems with the conventional Big Bang theory: the flatness problem (why does the universe have just the right density of matter and energy to give rise to a flat [Euclidean] space-time?) and the horizon problem (why is the universe so homogeneous, when the temperature and distribution of matter should not have had enough time to equalize?). The ultra-rapid burst of expansion solves both these problems by "smoothing out" the early universe, and some of the predictions inflation makes have been confirmed by observation.
Notably, Craig doesn't cite any evidentiary objections to inflation, and he does concede that most cosmologists accept it. Presumably, the source of his complaint is that although he accepts the Big Bang in general, he doesn't want science to have an answer for everything; he'd prefer these specific questions to remain unanswered so that he can attribute them to miracles. (We have to leave some gaps for God to fit into!) The "philosophical bias" he's complaining about is really science's bias toward solving problems, rather than giving up and declaring "God did it" as soon as we see something we don't understand.
Other posts in this series:
The Case for a Creator: It's All Because of Quantum
The Case for a Creator, Chapter 5
In discussing the kalam argument, William Lane Craig makes some points that touch on modern research in cosmology and physics, so I'll address those. He begins with the premise that "whatever begins to exist has a cause":
"It seems metaphysically necessary that anything which begins to exist has to have a cause that brings it into being. Things don't just pop into existence, uncaused, out of nothing." [p.99]
If we accept that William Lane Craig's notions of what is "metaphysically necessary" constitute binding law on the universe, then this is a strong point; otherwise, not so much.
In fact, the uncaused appearance of particles and events is a regular feature of quantum mechanics, the probabilistic theory that governs the behavior of the subatomic world. For example, the radioactive decay of an atom, according to our best understanding of QM, is uncaused in the strongest of senses. It happens completely at random, such that even a superintelligence possessing all facts in the universe could not predict precisely when a single atom will decay.
Another feature of QM is "virtual particles", which occasionally appear, at random and uncaused, out of fluctuations in the subatomic vacuum. Craig dismisses these as "merely theoretical constructs" [p.101], but unfortunately for him, virtual particles exert effects that have been directly detected and measured - such as the Casimir force, a slight attractive force that exists between two parallel conductive plates in a vacuum. In fact, engineers who craft microscopic mechanical systems have to take this force into account lest it cause their components to behave in unexpected ways.
"The quantum vacuum is not what most people envision when they think of a vacuum... it's a sea of fluctuating energy, an arena of violent activity that has a rich physical structure and can be described by physical laws... So it's not an example of something coming into being out of nothing, or something coming into being without a cause." [p.101]
Craig has done nothing to refute the claim that quantum events are uncaused, although his point is well taken that the subatomic vacuum is not "nothing". But in that case, he has to accept that "nothingness", as traditionally conceived of, does not exist - which renders specious his complaints about atheists who believe that particles and forces can emerge from the void. By his own account, all we're claiming is that these phenomena emerge from the quantum vacuum, which he himself seems to find perfectly plausible.
Craig's next point is a real howler:
"And then we have to ask, well, what is the origin of the whole quantum vacuum itself? Where does it come from? ...You've simply pushed back the issue of creation." [p.101]
And postulating a supernatural magician as the first cause evades this problem? Or is it that Craig has copyrighted the word "uncaused" and so he's the only one who gets to decide how it may and may not be applied?
This would have been a good place for a journalist to jump in and ask the obvious followup question of why postulating God as the first cause is not also just "pushing back the issue of creation", why God doesn't need a creator of his own. But Strobel seems to feel that Craig's blatant special pleading is something that will whiz by his likely readers without their taking notice, and he may well be right about that.
Logically speaking, there are only two possibilities for the ultimate origin of the universe: either there is an infinite regress of causes, or there is a first cause that cannot be explained in terms of earlier causes. Both atheists and theists should be able to agree that those are the choices. If there's an infinite regress of causes, it seems pointless to keep investigating further and further back; such a quest would be guaranteed never to end. If there is a first cause, though, we can productively ask questions about what sort of thing it might be.
This is where Craig and Strobel run into trouble, because we already have an excellent candidate for a first cause: the quantum vacuum, a timeless, chaotic state that continually spawns new universes through random statistical fluctuation. We already know that the vacuum exists and we know what many of its properties are, so no new entities are required in this explanation. In arbitrarily deciding that the vacuum must have a cause, however, Craig introduces a new entity - a supernatural deity which he believes has the power to create new universes. This is something we have no experimental evidence for, and it solves the first-cause problem no better than making the vacuum the first cause. Later in this chapter, Craig declares his allegiance to the principle of Occam's Razor, and this unnecessary extra step is the kind of superfluous add-on that the Razor is tailor-made to cut away. We have every reason to believe that the quantum vacuum is perfectly sufficient as a first explanation for the universe. Why multiply entities beyond necessity?
Other posts in this series:
The Age of Wonder
If you search the internet, it's not hard to find New Agers and others who think that the dawning of the age of reason was a mistake. They envision a more "holistic" approach, one that properly pays heed to the mystery and complexity of existence, and castigate science for being cold, unfeeling, heartless in its probing, reductionist scrutiny of the natural world. For example:
The reason things are advancing so slowly... is that science has neglected the (spiritual) indications necessary for its efficient performance - "with all your heart and all your soul...." -- indications that govern higher creativity and exist for the specific purpose of breaking the cosmic bank. The upshot is that science has become excessively expensive, bureaucratic and materialistic. The integration we need, external and internal, requires an incomparably more intense confrontation between the spirit of the researcher and the natural phenomena he is contemplating than what is currently practiced by even the most zealous of researchers.
And yet, the age of reason is also an age of wonder. The devotees of superstition and pseudoscience do not know what they are missing. In grasping after fool's gold, they have missed the true vein. The universe is a grander, more majestic and more beautiful place than any human being has ever imagined, or can imagine. The unsubstantiated and anthrocentric claims and inventions of people can never compare to the wonder and mystery held by reality as it truly is, and now that we truly have begun to understand how the cosmos works, we are at last getting a glimpse of that awe and wonder.
Consider what we witness when we peer into the cosmos with our telescopic eyes. We see light born billions of years ago in the crucible of dying stars, shining out across the cosmos and becoming ever more diffused, until at last our telescopes captured the lonely few photons that arrive bearing news of stupendous, ancient catastrophes. We see colliding galaxies, matter swirling into the abyss of black holes, and stars exploding with titanic force, sending out jets of energy visible across the known universe.
Our astronomy bears witness to births as well as deaths. We sift invisible light and see the ripples in the faint microwave glow that bathes all of space, distant echoes of the incomprehensible cauldron of heat and density in which the universe itself was born. We see dense nebulae where new stars are being born, burning away the dusty cradles of their formation like sunrise through fog. We see young planets circling their parent stars, their gravity cutting clear swaths through the veils of gas surrounding them. Most of the planets we have detected are hot Jupiters, but perhaps in some of these systems lurk embryonic Earths, awaiting their chance to cool and condense and one day become cradles of life of their own.
Turning closer to home, our emissaries have explored the solar system and brought back news of the other shores that await us. We have seen the shadows of the setting Sun creep across the mountains of the satellites of Jupiter, and we have seen the Earth rise in the night sky from the surface of the Moon. We have traveled the surface of Mars with our robot rovers, and sent landers parachuting down to the methane seas of Titan. Our age, for the first time ever in our planet's history, has sent ambassadors voyaging so far beyond our own shores that they could look back and see the Earth itself, our one and only home, as a pale blue point of light drifting in infinite dark.
Closer still, we have turned our gaze back upon ourselves, exploring our world in all its complexity. We have learned of the web of evolutionary kinship that connects all life on Earth. Everything - from human beings to redwood trees, from the lowliest cyanobacterium to the fluorescent tube worms on the ocean bottom - is a branch of the same family tree, every living creature a cousin, however distant, to every other.
We have delved down to the molecular roots of life itself, glimpsing the intricate choreography that turns inanimate molecules into living, growing cells, and the equally intricate assemblage that builds living cells into living beings. We have begun an effort to survey the tree of life, discerning the family relationships among countless species living and dead, and mapping the vast, frozen structure branching multidimensionally through those sections of design space that evolution has so far explored.
Traveling down into Earth's history, we have learned to read the record of the rocks and the chronicles they tell. We have retraced the multimillion-year drifting of the continents and learned of the planetary convulsions that wiped out whole branches of the tree of life and ushered in new ones in their place. We have glimpsed primordial eras long before humanity and envisioned the strange landscapes that once existed where we now place our feet.
All these findings far exceed the most fantastic imaginings of ancient mythology or modern pseudoscience, not least because they are true. In what other age of human history has anyone been able to look on a shooting star or a volcano and know what it really is? In what other age have we known the true age of the planet or understood the power source of the sun? These wonders and countless others, most of which are familiar and mundane to us, would have made people of past ages gasp in awe.
Out of the entire span of human history, these breathtaking discoveries have been made only in the last few hundred years, when we began to think and explore rationally. It was not crystals or prayer or Tarot cards that brought us these things. It was not superstition that was responsible, nor mysticism, nor credulous acceptance of extraordinary and unverified claims. It is the scientific method – institutionalized skepticism, rigorously and comprehensively applied – that has given rise to these wonders of understanding and accomplishment. As long as we human beings were willing to blindly accept the claims of others, to be meek and easily led, to believe without questioning, we remained frightened, brutish, short-lived and ignorant. There are some today who would gladly have us return to that state. Worse, there are some whose methods would inadvertently lead us back to that state, even as they hypocritically seek to take credit for the fruits and innovations of science while rejecting its rules.
But as for me, I remain a skeptic. I am proud to call myself a rationalist. And I will always fight against the proponents of darkness and unreason, because I believe that humanity has barely begun to tap its potential, and that if we continue the path of science, we may some day create wonders we currently lack the ability even to dream of.
The Uses of Pre-Scientific Cosmology
Before the dawn of the scientific age, humankind had only its unaided senses to examine the universe. Certainly, there were awe-inspiring sights, but those alone give little insight into natural phenomena. At night we saw the stars and the planets circle overhead; each season we felt the rains fall and the wind blow; and in moments of terror, we saw lightning split the sky and the earth shake under our feet. But none of these things gave any clue to what the true nature of the heavens might be.
Uncontaminated by knowledge, the theologians of antiquity spent centuries pondering the nature of the universe in empirical isolation, speculating about what kind of cosmos God would most likely create for us to dwell in. This can be a very useful test. Now that we in the modern world have some genuine data, we can compare it against these pre-scientific cosmologies. If they show a correspondence, we may be justified in concluding that more than human understanding went into the founding of these religions.
But, among the monotheistic religions of the West, there's little correspondence to be found. The god of the Old Testament is a small god, a provincial, tribal deity; he gives no indication that he is in any way concerned with anything other than one race of people dwelling in one particular region of the Mideast. And the creation story of Genesis is laughably small-minded, treating the entire universe as if it were nothing more than a backdrop for human concerns. As I wrote in "A Much Greater God":
[T]he god of the Old Testament... was so interested in the Earth that he created it with loving care and effort during the first three days of Genesis, while the entire rest of the universe - awesome collisions and explosions, space and time twisting and warping, stars burning and dying like flares with the energy of galaxies, massive black holes, pulsars like lighthouses, vast and intricately sculpted nebulae light-years across, a cosmos of a hundred billion galaxies each containing a hundred billion stars - was created on the fourth day, as an afterthought, for no reason other than to serve as signs and portents for the residents of the aforementioned Earth.
Christianity, which arose from the blending of Jewish theism with Greek philosophy such as Plato's idea of emanation or Aristotle's cosmic Unmoved Mover, had a broader focus and thought of itself as a universal religion in a way Judaism never did. Even so, it too remained moored in those local, tribal concerns, continuing to think of the small, ancient city of Jerusalem as the axis around which all the universe revolved. Islam, too, inherited the provincial outlook that considered its own culture and tradition the apotheosis of the cosmos.
All these people thought long and hard about what kind of universe God would probably create if such a being existed, and I see no reason to disagree with them. Therefore, the fact that the universe is unlike these ideas and like what we observe is evidence against this conception of God. To many religious groups, the idea of a vast and ancient universe was a terrible surprise. Of course, after several centuries, they've regrouped and are now claiming that this is what they expected all along, but their own predecessors' writings put the lie to that.
Furthermore, history makes clear that these were not idle speculations, ready to be altered as soon as better evidence turned up. These cosmologies were central to the various monotheisms. How else to explain stories like that of Giordano Bruno, a freethinker who believed the Earth was just one of an infinite array of worlds each with life of their own? Bruno's cosmology was not greeted as a potentially new way to understand the majesty of God's creation. Rather, he was tortured and burned at the stake by the inquisitors who plainly preferred a small god presiding over a small cosmos. Similarly, Galileo was forced to recant and confined to house arrest for the crime of studying the universe and daring to suggest that there might be aspects of it not already accounted for by theology.
These would be no more than inert facts about the past if they did not have so many parallels today. There are still millions of theists who believe in a tiny cosmos, created by God a scant few millennia ago and destined to end in the imminent future. There are still millions who believe the Earth is the only place that matters in the grand scheme of things. And there are still millions who want to make decisions that affect all of us on the basis of this medieval, hopelessly naive and arrogantly anthropocentric belief set. A deeper and more profound understanding, one that grasped the true scale of the universe and humanity's place in it, might give them a sorely needed measure of humility and a greater degree of reliance on reason.
I Don't Like to Brag...
...and I also wouldn't normally use this blog to inflict personal photos on you all, especially vacation photos.
But today I'm going to make an exception to both rules.
Anyone care to guess where I was last week?
Yes, you guessed it: after a three-hour plane flight and a two-hour drive along narrow, winding backcountry roads, I arrived at the Arecibo Observatory in Puerto Rico, the largest radio telescope in the world.
Here's me at the observatory complex's front gate:
The observatory itself was at the top of a long hill. Along the path on the walk up, there are scale models of the solar system. Here's the Sun (at the start of the walk) and a little way up, the Earth:
Further up the hill, the observatory itself rises into view above the trees. The lush tropical valley it's situated in is a gorgeous enough sight, but with the observatory towers rising above the treetops, it was practically a spiritual experience. (I imagine this must be how Muslims on pilgrimage feel when the Kaaba finally draws into sight.)
There are three towers which hold the support cables for the main reflector that's suspended over the dish. Here's one of them from below, in a shot that tries to convey just how huge they are:
Before seeing the observatory, there's a small visitor center and museum. Here's a shot from inside, one of the Nobel prizes that was won with Arecibo's aid - by Joseph Taylor and Russell Hulse, for the discovery of the first binary pulsar.
The next two pictures are kind of a funny story. After touring the exhibits in the visitor center, which were okay but nothing spectacular, I was becoming impatient to see the telescope itself. But the visitor center didn't have any windows that looked out onto it directly, and there didn't seem to be any way to get outside. I was starting to worry I'd come all this way for nothing. Then, on the second floor of the visitor center, I noticed a hallway leading back into some staff offices. There weren't any signs saying Employees Only, but it didn't seem like an area meant for casual visitors. I peeked in and noticed, at the end of the hallway, an employee lounge with picture windows that looked out onto the telescope. It was Saturday, so the adjacent offices were empty, and there were no employees of the visitor center around.
Well, what would you have done?
As it turns out, my cunning attempt at espionage was unnecessary. Through an ordinary, nondescript exit door at the back of the visitor center (and I don't know why it wasn't marked more prominently), you can stand on a platform overlooking the dish itself.
The sheer sense of scale doesn't fully come through in the pictures, though I tried to take shots that would convey it. The telescope is gigantic: the dish is almost a thousand feet across, and the reflector suspended over it is the size of a house. It's built into a giant natural valley in the jungle terrain.
And finally, here's me when I was invited to be the keynote speaker at a scientific colloquium that was going on while I was at the observatory. (Not really.)
Unfortunately, despite all the trail-blazing discoveries it's brought us, the future of Arecibo is threatened. Thanks to a selfish and short-sighted Congress, the National Science Foundation has been forced to make cutbacks in the past few years. Among other things, the NSF has told the staff of Arecibo (and Cornell University, which operates the telescope) that they must find outside sources for half of their budget within three years, or else the great observatory faces closure.
It doesn't have to be this way. The annual cost of operating Arecibo is a mere $8 million - small change, on the scale of the federal government. But while the government refuses to pay this comparatively paltry amount to continue to survey the deepest reaches of the universe, it continues to flush hundreds of billions of dollars into a wasteful, endless nightmare of war in Iraq. A tiny fraction of that money, if diverted to worthier causes, could pay enormous dividends both in fundamental science and elsewhere.
As grateful as I am to have had this experience, I don't want to be one of the last people to enjoy it. Arecibo deserves to be fully funded and to continue operating for many more years. The well of discovery has not yet come close to running dry, and if we seal it off, we'll be doing ourselves an enormous, senseless disservice. A bill, HR 3737, has been introduced in the House of Representatives to provide for Arecibo's funding. If you're an American, I ask you to contact your congressional representative and ask them to lend their support.
An Exercise in Perspective
If you're not familiar with the HubbleSite, you should be. The official website of the Hubble Space Telescope is rich with scientific background, news releases and announcements of new discoveries, and of course, jaw-dropping imagery of the cosmos, taken by one of humanity's most justifiably famous scientific instruments.
One of Hubble's newest images has left me feeling inspired, and I'd like to say a few words about it. But first, the picture itself:
This stunningly gorgeous image is a view of the spiral galaxy M81, one of the so-called "grand design" spiral galaxies due to its intricate and sharply delineated structure. In Hubble's view, the spiral arms of the galaxy are clearly visible, a vast whirlpool of stars, nebulae and interstellar dust revolving around the galactic core. M81 is about 12 million light-years from Earth, in the direction of the constellation Ursa Major, and is one of the brightest galaxies that can be seen from our planet (although it is just slightly too faint to view with the unaided eye, though easily seen with a telescope). M81 has lent its name to the cluster of galaxies in which it can be found, the M81 Cluster, sister to the Local Group of galaxies that contains our own Milky Way. Both the M81 Cluster and the Local Group, in turn, are part of the larger Virgo Supercluster, a group of galaxies spanning 150 million light-years.
M81 is similar in many ways to our own Milky Way. The galaxy's central disk contains relatively older, cooler reddish stars, while the spiral arms are home to hot, young blue stars, created by the rotation that sends waves of gas and dust sweeping across the galaxy like ripples in a pond, triggering bursts of star formation. At the center of M81, unseen, lurks a monster: a black hole with the mass of 70 million suns, sending out jets of radiation as raw starstuff swirling into its maw is churned and heated by the acceleration. Though the black hole itself swallows light and thus is invisible, in ultraviolet imagery we can see the white-hot accretion disk surrounding it, the last cry of matter falling into the abyss and out of our space-time continuum. (The Milky Way, too, has a central black hole, though ours has consumed all the gas and dust in its vicinity and has therefore become quiescent.)
Look again at that striking Hubble image. As beautiful as this picture is, I don't mind admitting that I feel a tremor of fear when I view it, especially at the larger resolutions. I feel this way because I know what that image represents: something so breathtakingly vast - something cosmic, in the truest sense of the word - that it beggars the imagination and overwhelms the ability of the mind to truly conceptualize it. Before the intricacy and scale of even a single galaxy, all of humanity and in truth the Earth itself is reduced to infinitesimal size, infinite insignificance. Compared to M81 or the Milky Way as a whole, we are not even a glimmer, not even a speck of dust. The cosmic forces that operate on the very largest of scales utterly determine our fate, beyond the ability of any person to resist or escape, and yet they are utterly incognizant of us. We could be brushed out of existence by them tomorrow, and in the grand scheme of things, the universe would never know that we had even existed. That, I think, is awe in the truest sense of the word: to stand before that which is so much greater than the self, and know yourself to be humbled by comparison.
Now, I'd like to propose an exercise in perspective. We inhabitants of Earth are embedded within the Milky Way, and cannot see it from outside. But if we could travel the staggering distance required to view our galaxy from the outside, from intergalactic space, it would probably look very much as M81 does.
Imagine, therefore, that this picture is of the Milky Way. In that case, our own sun, our solar system, our tiny and humble Earth would be located on the outer fringes, in one of the galaxy's spiral arms. On an image of the scale of this one, of course, they would be utterly invisible. This picture contains billions and billions of suns, and from this distance they are not distinguishable as individuals. Their light blends together into a hazy, glowing cloud, occasionally swirled through with dark lanes of dust. On the scale of this image, our mighty Sun would dwindle to a dust speck, just one of the thousands of stars whose light contributes to each pixel on your screen. The Earth itself, a tiny pale blue dot next to the Sun, would be as a dust speck to a dust speck. And humanity and all our mighty works, a thin, fragile skim of life on the surface of our world, would be even less altogether.
Consider the cosmos from this perspective, and then ask yourself: Do you believe that all of this was made just for us?
On our world today, there are still representatives of ancient religions who hold that the entire vast universe was created solely for man and placed under our governance - that the natural laws that apply on every scale across the cosmos and govern the origin and future evolution of billions of galaxies and trillions of stars were fine-tuned for humanity's benefit - that our tiny planet is the only place God cares about, the only place he is interested in - and that on our judgment day, all the stars and all the galaxies will be rolled together as a scroll and will cease to exist.
The presumption, the sheer arrogance of this belief boggles the mind. It would make as much sense for a single atom within your body, if atoms were conscious, to declare its dominion over you and assert that you exist only as a vessel for the drama of its individual salvation. Some other believers, though they do not go so far as this, still assert that the laws of nature single out humans as special, treating us as different from everything else that exists.
We are such a small, such an infinitesimal part of the cosmos as to utterly destroy any ridiculous claims that it was all crafted for our benefit. Next to even one galaxy, we are less than nothing. And M81 is not all there is, but rather only one galaxy among billions, one tiny part of a tableau so grand that even magnificent spirals like this one shrink to insignificance in comparison. When we peer deeply into space, we see a fractal-like scene, with even the tiniest possible patch of the night sky turning out to contain thousands of galaxies. The hierarchy of scale runs beyond anything we can visualize or comprehend. How could anyone believe that it was all put here for our sake?
A Tribute to Carl Sagan
Between the excitement of the midterm elections and the flood of atheism-related news that has occurred this month, there was one very important date that passed almost unnoticed, but that I would be remiss if I failed to mention. Namely, November 9 was the birthday of the famous astronomer and skeptic Carl Sagan. If he were still alive, he would have been 72 this month.
Sagan's scientific achievements were groundbreaking and hardly need me to recount them. During a time when the human species was taking its first tentative steps out into the solar system, he indisputably led the way. He was one of the primary scientific advisors on some of the earliest unmanned missions to study the planets, including the Pioneer, Viking and Voyager missions, and was the chief architect of the Voyager Golden Record that contains the images and music of our civilization, in case any extraterrestrial intelligence should happen to recover the probe millions of years in the future. He was one of the first scientists to hypothesize that Venus was boiling hot due to a runaway greenhouse effect, that Jupiter's moon Europa contains subsurface oceans beneath a layer of ice, and that a haze of organic molecules rains from the sky on Saturn's moon Titan, all of which turned out to be correct. He was also a well-known advocate of SETI, the Search for Extraterrestrial Intelligence, and one of the trailblazing advocates who turned it into a respectable area of scientific research in its own right.
But despite his considerable scientific achievements, Carl Sagan is best remembered as a popularizer who brought the wonder and awe of science and the importance of skepticism to the public. That this aspect of his career often outshines his prolific scientific work is a measure of just how good he was at it. He was the author or co-author of many books eloquently expressing the romance and power of scientific discovery, including Broca's Brain, The Dragons of Eden, Pale Blue Dot, The Demon-Haunted World, Billions and Billions, and Shadows of Forgotten Ancestors, many of which are still personal favorites of mine. But the best-known of all his roles was as the host of Cosmos, an award-winning PBS television series and accompanying book whose grand sweep travels from humanity's ancient past to the glorious diversity of life to the universe on the very largest of scales, and ends with an eloquent plea for peace and reason in the face of all the threats, mostly self-caused, that confront us. Cosmos is still the most widely viewed science documentary in the history of humanity; it is estimated that over half a billion people have seen it worldwide. I cannot think of a more worthy candidate for such an honor.
As my readers are probably aware, Carl Sagan's life was cut tragically short. I will let this great man tell the story in his own words, in an excerpt from the last chapter of his final book, Billions and Billions:
...one morning late in 1994, Annie [Sagan's wife, Ann Druyan] noticed an ugly black-and-blue mark on my arm that had been there for many weeks. "Why hasn't it gone away?" she asked. So at her insistence I somewhat reluctantly (black-and-blue marks can't be serious, can they?) went to the doctor to have some routine blood tests.
We heard from him a few days later when we were in Austin, Texas. He was troubled. There clearly was some lab mixup. The analysis showed the blood of a very sick person. "Please," he urged, "get retested right away." I did. There had been no mistake.
Sagan had become ill with myelodysplasia, a rare and deadly form of leukemia. The only hope for survival was a bone marrow transplant, and by a stroke of good fortune, his younger sister Cari matched in all six genetic compatibility factors that would be needed for a successful one. Sagan went through several grueling rounds of chemotherapy, radiation and transplants, but the disease recurred, a few malignant cells escaping each round of treatment to kindle a new flare-up. In the end, it seems, he triumphed over myelodysplasia; but the treatment had taken a terrible toll, and his weakened immune system could not fend off a bout of pneumonia that wracked his lungs and, ultimately, ended his life. Ann Druyan was at his side as he died, and wrote in the epilogue to Billions and Billions:
Contrary to the fantasies of the fundamentalists, there was no deathbed conversion, no last minute refuge taken in a comforting vision of a heaven or an afterlife. For Carl, what mattered most was what was true, not merely what would make us feel better. Even at this moment when anyone would be forgiven for turning away the reality of our situation, Carl was unflinching.
...For days and nights Sasha [his daughter] and I had taken turns whispering into Carl's ear. Sasha told him how much she loved him and all the ways that she would find in her life to honor him. "Brave man, wonderful life," I said to him over and over. "Well done. With pride and joy in our love, I let you go. Without fear. June 1. June 1. For keeps..."
The rawness of these words, written so soon after Sagan's death, still stings my eyes even as I type this. The world is a slightly darker place without him, and though he has now been deceased almost ten years, I am often reminded of how much need we still have of him. His passing preceded, by only a few years, my discovery of his writings and my enthrallment by them. It is one of my few regrets that I never had the chance to write him a letter to let him know how much his work meant to me.
But more so, I regret knowing that he had the terrible misfortune to die before seeing so many of the wonderful discoveries humanity has made in the ten years since, many of which can be credited to his legacy. There is the Stardust mission that flew through the dusty corona of the comet Wild-2 and became the first spacecraft to return comet dust to Earth; the Wilkinson Microwave Anisotropy Probe that has revealed the most detailed picture ever taken of the cosmic microwave background radiation, conclusively determining the age and large-scale structure of the universe; the Cassini-Huygens mission to Saturn and its moons, including a lander that parachuted onto the surface of Titan itself; and the robot rovers Spirit and Opportunity, which even now are exploring Mars and uncovering astonishing evidence that, though the planet is now a freezing dry desert, it had a warm, wet, Earthlike past. Such discoveries would undoubtedly have brought Sagan much joy. I am sorrowful that he missed them, for he more than anyone else deserved to live to see them; but I find some small comfort in knowing that they at least were made, and that there are many more people eager to join the pursuit of scientific progress, some of whom were perhaps inspired to do so by Sagan himself, who will continue to raise the banner of discovery and raise our eyes to the awe and wonder of living in the cosmos.
Though many new brilliant and eloquent scientific popularizers have emerged over the past ten years, none of them match up to Carl Sagan. I mean no insult by saying so, and I trust none will be perceived. If, as the man himself said, science is a candle in the dark, then Carl Sagan's candle burned brilliantly against that dark, glowing like a miniature sun. In that light was an eloquent hope of all that humanity could become, and a poignant reminder of how much we have in common and how insignificant the things that divide us truly are. Though we can never replace him, we can do the next best thing and carry forward the ideals he defended so powerfully. Rest in peace, Dr. Sagan. We will remember, and you have my word that we will not allow your candle to go out.
Another Brief History of Time
I recently came across a gorgeous Flash presentation briefly chronicling the history of the universe, from the Big Bang to humanity. Check it out: Evolution - What Next? Click on the red "Time Slider" arrow to get it started, then click and drag the slider along the timeline. I haven't explored the rest of the site in detail yet, but there seem to be many more Flash animations on other topics relating to biology.
Credit to Table of Malcontents for the original link.