What We Believe But Cannot Prove: Today's Leading Thinkers on Science in the Age of Certainty.

What We Believe But Cannot Prove: Today's Leading Thinkers on Science in the Age of Certainty

Edited by John Brockman (NY: HarperCollins, 2006); 252 pp.; $18.95 paper; ISBN: 13:978-0-06-084181-2.

THOSE WHO WONDER what cutting-edge scientists might ponder outside their classrooms and laboratories need wonder no more. In What We Believe But Cannot Prove, "intellectuals in action" speculate on the frontiers of science, hard and soft. Skeptics, however, shouldn't be deceived by the title. An ample majority of the more than one hundred teasingly short essays included will sate the intellect's appetite for both facts and reasoned theory. John Brockman's new collection features the world's most celebrated and respected scientists and their musings on everything from human prehistory to cosmology and astrophysics, from evolution to extraterrestrial intelligence, and from genetics to theories of consciousness.

Biologist and geographer Jared Diamond is convinced, but says he can't prove, that the first Americans and Australians arrived very recently, approximately 14,000 years ago and 46,000 years ago, respectively. Diamond's "guess" is based on archeological evidence for such populations and on the fact that most large mammals on these distant continents disappeared shortly after such dates. When humans arrived in Australia and the Americas, he reasons, they easily slaughtered giant animals, the counterparts of which survived in Africa, Asia, and Europe largely because they were afforded the luxury of time: "millions of years to learn fear of human hunters, whose skills evolved slowly."

But life is hardly unique to this world, according to Discover magazine editor Stephen Petranek, who predicts the detection of another Earthlike planet within ten years. Mars has disclosed evidence of a brackish sea and a frozen lake. The Milky Way nebula, Sagittarius B2, has revealed data suggesting the presence of aldehyde molecules that typically assist in the formation of amino acids, and scientists have reported their discovery of glycolaldehyde, a simple sugar. Astronomers have recently located smaller planets, more likely to be rocky than gaseous, orbiting sun-like stars, and have identified copious amounts of water near and between stars. "Everything that life needs," Petranek writes, "is out there."

Which isn't to say that such life is or will ever be intelligent, warns physicist Kenneth W. Ford. While microbial life might indeed be common in our galaxy, "the existence of intelligent life ... is another matter." For lack of alternatives, Earth is our example: although microbes have flourished for 75 percent of terrestrial history, intelligent life has prospered for only 0.02 percent of that time.

Natural philosopher Paul C. W. Davies, on the other hand, seems more conflicted over the issue. Although he categorically rejects popular statistical arguments extrapolating on the enormous size of the universe alone, and admits that "no known law of physics or chemistry favors the emergence of the living state over other states," Davies nevertheless concludes that "we are not alone because life seems to be a fundamental, and not merely an incidental, property of nature." If nothing else, the evidence seems to suggest that circular reasoning is every bit as common as intelligent life.

Drawing readers from the outlying back to the intimate, experimental psychologist Steven Pinker professes that human minds are richly mechanized and organized into focused cognitive systems. Cerebral homogeneity "is an illusion," he contends to his neuroscientist critics. Although the cortex may appear consistent, it might contain connectivity patterns and synaptic biases that facilitate different complex functions. To his geneticist detractors who remind us that the human genome probably contains as few as 25,000 genes, Pinker identifies a wealth of information contained in so-called junk DNA, the non-coding portions of the genome, "whose size, spacing, and composition could have large effects on how genes are expressed."

Anti-abortionists and animal rights devotees might quarrel with philosopher Daniel Dennett, who proposes that an oral or sign language is prerequisite to consciousness, defined "in the strong sense of there being a subject, an I." Neither infants nor animals are actually conscious, Dennett contends, because they own no past, because they have no ability to enjoy or suffer from their experiences. Evolution, unlike Walt Disney, Dennett notes, doesn't supply organisms with such unnecessary abilities.

Cognitive scientist Alison Gopnik argues instead that young children are actually more conscious than adults. Babies generally learn better, she observes, because as adults age, they typically "gain conductive efficiency but lose plasticity." In other words, mature persons tend to either perform tasks habitually or focus on them single-mindedly. Although Gopnik initially claims to disagree with Dennett, she eventually appears to recognize that she has merely defined consciousness differently, in terms of external rather than internal awareness. "Babies," she finally confesses, "may be more conscious in one way and less in the other."

Potential disputes over age-relative consciousness are apparently somewhat moot for psychologist and neuroscientist Robert R. Provine. "The argument," he contends, "is not that we lack consciousness but that we overestimate the conscious control of behavior." When subjects are asked to explain their actions, they often confabulate, offering "post hoc misattributions" for such behavior, perhaps in efforts to either defend or promote themselves. By focusing on the issue of whether humans have any more conscious control over their actions than animals do, however, Provine tenders a hypothesis perhaps more appropriate to a philosophical discussion regarding the existence free will.

Some such essays are less helpful and inspiring than others, of course. Evolutionary biologist Richard Dawkins abruptly declares that Darwinian natural selection "is true all over the universe." Physicist Lee Smolin argues that quantum mechanics is merely an "approximate description" and an unfinished theory. One wonders whether certain essays were included due to the contributor's station rather than the contribution's substance.

Regardless, What We Believe But Cannot Prove offers an impressive array of insights and challenges that will surely delight curious readers, generalists, and specialists alike. Science is intimidating for the vast majority of us. But John Brockman has grown deservedly famous in recent years for his capacity and penchant to lure these disciplines and their leading practitioners back to Earth where terrestrials are afforded opportunities to marvel at the intellectual and creative magnificence of science in particular and, more generally, at our species' immeasurable potential in all pursuits.

Kenneth W. Krause is a former prosecutor and criminal defense attorney with degrees in law, history, literature, and fine art. Books editor for Secular Nation, he has also recently contributed to Free Inquiry, Skeptic, Skeptical Inquirer, and the Humanist. He may be contacted at [e-mail].