Understanding starstuff

INTELLECTUAL revolutions -- unlike, say, the French kind -- are often barely noticeable, involving no shouting, storming of barricades or guillotining. Sometimes it’s hard to tell that anything at all has occurred: People simply begin to understand something differently -- and once they have, they can scarcely remember a time when it wasn’t understood that way.

Such is the revolution that Cornell astronomer Carl Sagan, a veteran of NASA’s planetary program, produced among television viewers in 1980, when “Cosmos,” his 13-part series, appeared on PBS. It was simultaneously published in book form by Random House and became a prodigious bestseller. Many of us learned, or for the first time fully grasped, that we are “made of starstuff,” that “[e]volution is a fact, not a theory,” and that the whole human era is a near-invisible sliver in the lower right-hand corner of the cosmic calendar. We understood where we were -- essentially, nowhere in particular -- and when and how we got there. It was a mass consciousness-raising that might have dazzled (and possibly frightened) Copernicus.

Sagan became, particularly after “Cosmos,” a public intellectual -- a passionate advocate not just of science and space exploration but of nuclear disarmament -- and remained one until his death in 1996 at age 62. In 1985 he was invited to give the Gifford Lectures on Natural Theology at the University of Glasgow. These have now been collected and edited by his wife, Ann Druyan (who was also his collaborator on “Cosmos”).

The title she chose -- “The Varieties of Scientific Experience” -- is a deliberate echo of William James’ “The Varieties of Religious Experience.” James, a psychologist, was an agnostic but free of the mulish antipathy to spiritual speculation that characterizes freethinking, then and now. His book too was the outcome of the Gifford Lectures, a series established in the late 19th century to examine the theology derived from observation of the natural world (as opposed to supernatural, “revealed” religion). James delivered his Gifford Lectures in 1901-1902 -- to the great annoyance of many of his academic colleagues, who could not abide any sort of theology, natural or not. Heretically he concluded: “The whole drift of my education goes to persuade me that the world of our present consciousness is only one out of many worlds of consciousness that exist.... I can, of course, put myself into the sectarian scientist’s attitude, and imagine vividly that the world of sensations and scientific laws and objects may be all [there is]. But whenever I do this, I hear that inward monitor ... whispering the word ‘bosh!’ ”

More than 100 years later, we’re in the middle of another fierce and fulminating clash between science and religion, which has spawned a raft of polemics and may explain the new book’s subtitle. In fact, Sagan interpreted his Gifford lectureship fairly loosely, with an emphasis more on the search for natural truth than on a “search for God.” He would not have seen much difference: At the outset, he informs his listeners that “[t]he word ‘religion’ comes from the Latin for ‘binding together,’ to connect that which has been sundered apart.... And in this sense of seeking the deepest interrelations among things that superficially appear to be sundered, the objectives of religion and science, I believe, are identical or very nearly so.” Then he is off -- with the help of a stunning set of slides, beautifully reproduced here -- on a tour, through space and through time, of the known universe.

Sagan finds order and majesty there, of course. But he also finds extreme violence -- in supernova explosions and the even greater chaotic violence at galactic centers. In such a universe, where “worlds are born and worlds die” continually, he comments on the difficulty of entertaining “the traditional Western sense of a deity carefully taking pains to promote the well-being of intelligent creatures.” Yet Sagan does suspect that intelligent creatures exist everywhere, not just on Earth. Organic molecules are ubiquitous in the universe. You can find cyanide, for instance, in the tails of comets. He reports that this unsettling discovery had been made by 1910, when Halley’s comet was due to arrive once again in our skies. Consequently “there were national panics in Japan, in Russia, in much of the southern and United States. A hundred thousand people in their pajamas emerged onto the roofs of Constantinople” and “people all over the world ... committed suicide.”

Halley came and went in 1910 with no discernible earthly consequences. However, Earth was undoubtedly seeded with organics early in its history by infalling comets and meteorite impacts. In a process that, as the scientific catchphrase goes, is not yet well understood, those compounds eventually formed molecules that were able to reproduce themselves and later to morph into the planet’s first life-forms, one-celled bacteria. Later still, in the Darwinian struggle of the living to survive, multicellular organisms developed. Then came the sea creatures, the continental flora and fauna and us -- and somewhere in that more than 3.5-billion-year stretch (by means also not yet completely understood) intelligence arose. Why? For the simple reason, Sagan says, that “[t]he selective advantage of intelligence is clearly high.”

Since our part of the universe is no different from any other, the same process must have been going on -- must be going on, will go on in the future -- elsewhere. Sagan explains that what makes the ubiquity of life probable, despite its staggering complexity and its entirely random origins, is simply the vast size of the universe and the oceans of time available to evolution and its powerful tool of natural selection. Billions of worlds and billions of years. We used to laugh at such locutions; they were the stuff of jokes on late-night talk shows. Don’t laugh. It’s why you’re here.

Still, Sagan was well aware that intelligence, if ubiquitous, is rare. He saw us as an endangered species, and he was willing to invoke religion in aid of nuclear disarmament: “It seems to me this is the issue above all others on which religions can be calibrated, can be judged. Because certainly the preservation of life is essential if the religion is to continue. Or anything else.... I believe there is simply no more pressing issue.... Whatever personal hopes we have for the future, ambitions for children and grandchildren, generalized expectations for future generations -- they are all fundamentally threatened by the danger of nuclear war.”

As for natural theology, Sagan’s came down to science as “informed worship.” With James, he believed that “there are parts of our selves that are hidden from us” and he further defined science as a “two-pronged investigation into the nature of the world and the nature of our selves.” It is an enterprise that seems to have filled him with anticipation. “If there is ... a continuum from self-reproducing molecules, such as DNA, to microbes, and an evolutionary sequence continuum from microbes to humans,” he asked the academics at the University of Glasgow, “why should we imagine that continuum to stop at humans?” *