The Diversity of Life.

We meet, and need, leadership in many guises. Sometimes we crave statesmen or generals; but other moments require prophets. Jeremiah began his lamentations over the captivity of Jerusalem with a powerful image of emptiness: "How doth the city sit solitary, that was full of people .... She that was great among the nations ... how is she become tributary." He then switched to a biological metaphor (Lamentations 1:6): "Her princes are become like harts that find no pasture; and they are gone without strength before the pursuer." If, as Pogo said, the enemy is us, then we are the huntsmen, the destroyers of habitat, the blight upon former plenitude.

We all know about dodos and great auks as abstractions or stuffed specimens in museums. But for most people most of the time, the wave of extinctions unleashed by human depredation of our earthly environment ranks as something distant from immediate locales and concerns (however global the ultimate threat). Therefore we need prophets to shake the souls and grab the attention of those who have eyes but see not. The Diversity of Life is a deft and thoroughly successful mixture of information and prophecy.

Wilson has composed his text in three parts: first, on natural extinctions (and recoveries) at scales rising from the local and historical (Krakatoa in 1883) to geological and global (the five great mass dyings of our palaeontological record); second, on the evolutionary construction and richness of biodiversity; and third, on human disruptions, malfeasances and (if we are both lucky and smart) potential reversals and solutions. The connecting thread is the familiar theme that our current geological micromoment of anthropogenic carnage ranks as a full-blown sixth episode of mass extinction, not as one of those pervasive blips that mark planetary business as usual--in other words, a rare and portentous punctuation, not a part of the permeation. (On this connecting theme, and with apologies for a petty comment from my own parish, may I request that subsequent printings of this book--a great and fit work destined to survive and thrive well into the next millennium--correct the numerous palaeontological errors scattered throughout: foraminiferal tests are generally calcareous, not siliceous; Pangaea did not congeal until the late Palaeozoic, and therefore did not exist during the Ordovician and Devonian mass dyings.)

But what combination of influences can recast a celebrated academician into the unfamiliar role (in our church) of effective prophet Above all, of course, one must have a cause--and what purpose could be more noble than speaking for (the literal meaning of prophet, by the way) the multitude whose voices do not broadcast on human wavelengths--the 1.5 million or so described species that stand for an unknown bounty ranging up to 100 million or more? Prophets must speak for uncompromised principles, though we all know that practical solutions will fall short. Wilson's credo is ringing and simple: fight to save all taxa. He writes:

In democratic societies people may think that their government is

bound by an ecological version of the Hippocratic oath, to take no

action that knowingly endangers biodiversity. But that is not

enough. The commitment must be much deeper--to let no species

knowingly die, to take all reasonable action to protect every species

and race in perpetuity.

Putting such a credo into action requires great powers of persuasion in two different spheres. First, knowledge: few nonspecialists appreciate either the taxonomic richness of nature or the magnitude of current loss. (Wilson estimates that "a fifth or more of species of plants and animals could vanish or be doomed to early extinction by the year 2020 unless better efforts are made to save them".)

Moreover, we who study biodiversity face the correlated problem of inadequate respect for our efforts. We are too often seen as superfluous accountants--mere listers and arrangers, scribes in a catalogue of particulars containing no messages about general theories of natural order. And yet, the historical data of unique items in contingent sequences are as intrinsically valuable and theory-laden as the most rigidly predictable and repeatable behaviour of molecules or planets in deterministic systems. Data of our sort, after all, fuelled Darwin's documentation of one of the great generalities in our intellectual history: evolution by natural selection.

The number of trained taxonomists has been so depleted that the diversity of many groups of major economic importance cannot be studied at all. (Wilson reports, for example, that only one scientist in North America studies the classification of oribatid mites on a full-time bask--although these soil-dwelling arthropods are ubiquitous consumers of humus and fungal spores, and are "therefore key elements of land ecosystems almost everywhere.") Yet there is a way, if only we had the will (emerging from an understanding of importance); nature's richness need not stymie us. Wilson reports that, at the "cautious pace" of 10 species per year, 25,000 professional lifetimes of 40 years could lead to the description of 10 million species (a low but popular estimate of global biodiversity). Such a number still represents "less than 10 per cent of the current population of scientists active in the United States alone."

Second, empathy (the main thrust of prophecy): Jesus said that the truth shall make us free, but how can we transfer to the gut of feeling (and desire for action) what we may know in our heads? This problem is particularly difficult when most victims are not starving humans (at least not yet), or even furry pandas, but cockroaches, nematodes and mites.

The practical reasons for preserving unknown species (primarily agricultural and pharmacological) are well documented, and thoroughly discussed by Wilson. But I have always thought that a movement for salvation cannot succeed without a primary grounding in the better and broader arguments: ethical (what right has a tiny twig to expunge great limbs from its nurturing tree?) and aesthetic (the sheer joy of such limitless variety versus a depleted landscape of people, dogs, rats, pigeons and flies). But these moral and emotional arguments need both knowledge and love of nature, and how do we foster the latter in an urban society offering little direct exposure to most citizens?

We can take people to wilderness (so-called |ecotourism'), though no general solution can emerge from this basically elitist strategy. We can rely upon film and other burgeoning media of our electronic revolution, but these vicarious strategies too often foster passivity. I am old-fashioned enough to believe in the primacy and efficacy of great writing (well-illustrated of course), and I thank all our predecessors for their legacy of eloquent support. I have often argued that the best popular writing about science falls into two traditions: the Galilean or rationalist that locates the thrill of nature in its intellectual puzzles (with Huxley, Haldane and Medawar as the great practitioners since Darwin's day) and the Franciscan or lyrical that can capture the visceral beauty--|nature poetry', if you will, from St. Francis of Assisi through W. H. Hudson, Henri Fabre, and Loren Eiseley or John McPhee in our day. Wilson is a celebrated professor at an institution placed (however undeservedly) on a pinnacle of rarefied intellectual etheriality, but when he lets go (as he does here, and as I wish he would do more often), he is the finest Franciscan naturalist of our time. Wonderful writing! (I say this with some jealousy as the most committed of Galileans who, by personal limitation, can do no other. Ne supra crepidam sutor judicaret.)

Reviews of such praise must also disgorge some dyspepsia, and I am not without my criticisms. It is no secret that Wilson and I look at evolution quite differently (from joint residence within such an ample Darwinian estate), and I do deplore some unkind and unfair statements about punctuated equilibrium. But if there were ever a subject for beating the swords of professional dispute into ploughshares of joint action, then preservation of biodiversity is our common strength and shield. (Good Lord, we can even bring animal rights activists--and, dare I say it, even some creationists--under this banner; so why should such lesser disputes as adaptation and contingency, or human sociobiology and culturally driven flexibility, not share common cause?)

Still, I do wish that I could dissuade my colleague from his commitment to pervasive adaptation and progress (by showing him the incredible yet comprehensible strangeness of the fossil record viewed in detail). I confess that I do get cross--since he knows as well as I do that we live in the Age of Bacteria (as it was in the beginning, is now and ever shall be, until the world ends)--when I read, in his book, the old ladder spiel of superannuated textbooks: "They [the first land invertebrates] were followed by amphibians ... and a burst of land vertebrates ... to inaugurate the Age of Reptiles. Next came the Age of Mammals and finally the Age of Man." This, after all, is the very enshrining of arrogance and exaggerated self-importance that we must avoid if we are ever to take fellowship with nature seriously--and thereby avert the biodiversity crisis.

I also cannot accept the too-facile argument that we are likely to prevail thanks to an innate "biophilia, the connections that human beings subconsciously seek with the rest of life. To biophilia may be added the idea of wilderness .... Wilderness is a metaphor of unlimited opportunity, rising from the tribal memory of a time when humanity spread across the world."

How can this be? Why should these valued features be deeper, more innate, more definitive of our nature, than our rapacity? Was it any less natural to kill all the moas of New Zealand, all the mammoths of North America? Surely for each biophile in the United States, there are ten who would kill a deer for sheer sport, rather than for needed food; ten who will build the suburban shopping mall for each cry of "woodsman, spare that tree."

We cannot win by appealing to an innate urge stronger than competing drives. Does Wilson really view these competing drives as mere cultural overlay, with biophilia and love of wilderness as primary biology yearning to emerge? Sorry, but such a view, to me, is romantic nonsense (and I use this word in the literal, not the pejorative, meaning). Here I do state my preference for rationalist Galilean solutions over pure Franciscan lyricism. The best way must be learned and studied, not simply freed from an internal reservoir.

We are a swirling congerie of biological potential for good and bad, preservation of biodiversity or global clearcutting. The tendencies for good and right resolutions are within us, but so are the propensities for evil and short-sightedness. Let the spring of En Gedi be a symbol for the fount of goodness within us. Wilson recounts the story of his visit to this wondrous oasis of greenery and biodiversity in the harsh Judean desert (and I could tell a similar tale of my own encounter). En Gedi is the Franciscan paradise of Solomon's song: "My beloved is unto me as a cluster of camphire in the vineyards of En-gedi" (Song of Songs 1:14). And En Gedi is also the great Galilean symbol of moral restraint upon murder, for here David could have ambushed a defenceless Saul, yet desisted (I Samuel, 23-24).

Wilson quotes the wonderful motto of the Senegalese conservationist Baba Dioum--and what better union of love and knowledge could we seek to unleash and empower the right side of our vast biological potentiality: "In the end, we will conserve only what we love, we will love only what we understand, we will understand only what we are taught." This union of love and knowledge is called wisdom, and wisdom, like nature, is truly "a tree of life to them that lay hold upon her" (Proverbs 3:18). With a proper fusion of Galilean intelligence and Franciscan love, we may be able to honour E.O. Wilson as a prophet in his own country--which has become, in our truly ecumenical age, the whole world. ([dagger]) Edward O. Wilson, The Diversity of Life (1992).

Stephen Jay Gould(*) Museum of Comparative Zoology, Harvard University. This book review appears in its original form as first published at 361 Nature 311 (Jan. 28, 1993).