God's recipes give food for

Scientists," wrote Darwin's contemporary Samuel Butler, "are the priests of the modern age, and they must be watched very closely." Butler, author of The Way of All Flesh and Erewhon , argued long before the first computers (in the age of steam engines) that machines were evolving faster than humans and that Darwin, by emulating Newton and making natural selection a completely mechanical theory, had "taken the life out of biology". Was there not more to evolution than the blind operation of rules? Did one's choice not count? Were non-humans not able to choose, too? And if evolution was progressive, how could it be progressive towards humans, when machines were surpassing us?

Butler had a point. Ever since Newton put alchemy and scriptural studies on the back burner to concentrate on a more promising dish - the linking of heavens to earth by pure mathematics, and thereby appearing to see the mind of God - scientists, especially physicists, have attempted to follow Newton's example. And the brazenness was rewarded.

Although one can argue that the horrors of the second world war represent a Faustian come-uppance for the scientist-priests who dared to copy God's recipes, science has been a feast for the technological tongue as well as the inquiring mind: not just the modelling of gravity leading to human footprints on the moon, but the nuclear secrets of the sun and stars, the infectious nature of disease (once attributed to demons), and the chemistry of replication have been cooked up on science's Promethean stove.

Today, the far-out speculations of scientists show no natural boundaries - but perhaps, considering the historical relationship between scientific progress and human insignificance, they should. They include theories on the big bang and before (declared off limits by the pope but investigated by Stephen Hawking), the potential status of the universe as a giant computer (for example, the work of Stephen Wolfram), the role of intelligent life in overcoming energy constraints to insure its own immortality (Frank Tipler), the existence of life throughout the universe, the effect of the future on the past (John Wheeler), the direction of universe-conquering life (Freeman Dyson) and the creation of new universes (Lee Smolin). Such speculations on plumbing the depths of eternity, identity and cosmic purpose, though they often involve a big role for biology, are often put forth by physicists.

It is thus with considerable expectation that one opens The Emergence of Everything by biophysicist Harold Morowitz, a member of the science advisory committee of the Santa Fe Institute. Unlike many "complexity theorists" whose biological ruminations are linked more to computer patterns than to organisms, Morowitz is not primarily a mathematician.

Excited early in his career by the links between energy and biology, his Energy Flow in Biology (1968) advances what is sometimes known as "the fourth law" of thermodynamics: "In the steady-state systems, the flow of energy through the system from a source to a sink will lead to at least one cycle in the system."

In related cryogenic experiments, he showed that cells brought to temperatures near absolute zero could be revived. More recently, realising the need to supplement energy studies with detailed chemical analysis, Morowitz has been engaged in the quest to find a "universal metabolic chart", the biological equivalent of the periodic table. "Metabolism," he says, "recapitulates biogenesis." The chemical cycles of modern cells may contain traces not only of their bacterial ancestors but of life's origins.

Theoretically these trails, thermodynamic cycles, are chemical fossils more than 3.5 billion years old, the remnants of the robust gradient-reducing means by which matter first came to life. And it is here, perhaps, in the assumed necessity of a transition from non-life to life, that we need to watch Morowitz and other scientists, as Butler suggests, very closely.

Morowitz points out that matter is "informatic": when particles behave "nondynamically" (according to rules that apply only when they are together), they behave as if they have knowledge of each other's presence.

Mentioning the role of compounds associated with ATP (adenosine triphosphate), the energy-storage compound common to all cells, Morowitz suggests a major link between physics and biochemistry, and that it may govern the emergence of beings on the way to becoming thinking humans. He wonders about the dual role of adenine, one of the four bases in DNA and RNA, in energy transfer and the genetic code: "An understanding of adenine seems to lie close to the biochemical secrets of life."

Beginning with the "Primordium" and making pit stops for things such as cells, Morowitz takes us through 28 steps of emergence. By the time we get to "Athens and Jerusalem" of this teleological series that Morowitz suggests may be underwritten by algorithmic rules, one has to sigh and accept literally his claim that he has looked to Jesuit priest Teilhard de Chardin as his "role model" in "speculative scholarship". Morowitz wisely prefers real-life examples of emergence, as opposed to the theoretically infinite types of complexity that can be generated by computer rules. And yet one wonders why, if, as he says, "in the absence of an agreed-upon metric of complexity, it is difficult to formulate a precise analysis", we should be asked to contemplate as scientific the untestable Judaeo-Christian notion that man is integral to some vast divine cosmic plan.

Dorion Sagan is a science writer and Lynn Margulis is professor, department of geosciences, University of Massachusetts, Amherst, US.