Unbeliever's Quest

CARL SAGAN, THE FAMOUS SCIENTIST and author, never asked for anyone to pray for him, although in his final illness many people did anyway. For two years prayers for his health filled the great Cathedral of St. John the Divine in New York. They rose (if prayers do rise) to the heaven Sagan had never seen in all his years of searching the sky, and were heard (if prayers are heard) by the God Sagan never called on. And God (if he exists) let Sagan die anyway, late last year, at the untimely age of 62, leaving behind a wife, five children and much unfinished work on the earth he loved so well. But he died in what amounted, for him, to a state of grace: resisting the one temptation to which almost everyone submits in the end, the temptation to believe.

Not that the Kingdom of Heaven held no interest for Sagan, an astronomer who found the solar system too confining for his speculations on cosmic origins, human consciousness and evolution. For most of the last decade of his life he engaged in a wide-ranging dialogue with religious leaders on the question whose answer held the potential to put either preachers or cosmologists out of business: does God exist? He argued the negative, although his formal position was agnostic, awaiting proof. On the other side were primarily mainstream, liberal Protestant clerics, such as the Rev. James Parks Morton, then dean of St. John the Divine, and the Rev. Joan Brown Campbell, general secretary of the National Council of Churches, whom Sagan met in the environmental movement. But he also exchanged views with believers of a more conservative bent, such as Robert Seiple, head of the Christian relief organization World Vision. Sagan was fascinated by the phenomenon that educated adults, with the wonders of science manifest all around them, could cling to beliefs based on the unverifiable testimony of observers dead for 2,000 years. ""You're so smart, why do you believe in God?'' he once exclaimed to Campbell. She found this a surprising question from someone who had no trouble accepting the existence of black holes, which no one has ever observed. ""You're so smart, why don't you believe in God?'' she answered.

Sagan never set out to finish the work of the Enlightenment singlehandedly. ""I started out very much enjoying the idea of an omnipotent, omniscient, benevolent God who like a benign parent was watching out for me,'' he wrote to one of his correspondents. ""I was brought to skepticism by the slow realization that the "evidence' [for religion] is anecdotal . . . But if there is evidence of such a God, or any other God, I feel it is my responsibility to try and know about it.''

For that matter, Sagan's early career suggested he had the potential to become as big a public nuisance as Shirley MacLaine. Twenty years ago, as a scientist on the Viking Mars probe project, he was known as a particularly visionary believer in the possibility of life on other planets, to the point where some of his colleagues at NASA considered him a flake. But it was only the possibility he believed in. When Mars landers found nothing but rocks, he accepted the evidence--as, years earlier, he had himself published a seminal paper showing that Venus was too hot to support life. Thus ""Carl's major contributions to science each flew in the face of his own most cherished expectations,'' remarks his wife and sometime collaborator, Ann Druyan. He thought believers should be just as willing to jettison their beliefs in response to evidence. A religion whose highest sacrament is heresy might have won Sagan's allegiance, but he never found one.

Sagan developed many of these ideas in his 1995 book, ""The Demon-Haunted World,'' a defense of science against the superstitious nonsense that he saw in American culture, from alien abductions to ""recovered memories'' of satanic ritual abuse. He managed to suggest, with considerable circumspection, that the evidence for most religion is not very much stronger. Sagan's insistence on dealing only with ""evidence'' put his correspondents at a seeming disadvantage, at least until the time Campbell asked him, ""Carl, do you believe in love?''

""And he said, "Of course I do.' He was very much in love with his wife.