Better than bacteria

Colin Tudge takes issue with the PC line on evolution; Life's Grandeur by Stephen Jay Gould, Cape, pounds 16.99

Life's Grandeur, Gould tells us, is "a companion volume of sorts to my earlier book, Wonderful Life." And so it is. That was largely spurious as well. Both are magnificent flights of rhetoric, unique in the canon of 20th-century science. But, in the end, they're a massacre of straw men, most of whom were heavily mildewed well before Gould set about them. Gould's prose is indeed brilliant if a shade otiose - must trees always be "arborescent"? - but its fury signifies nothing very much and what it does is largely beside the point. It really is time that somebody pointed this out.

Thus, in Wonderful Life , Gould told us that living things have not really become more varied this past 500 million years as we thought they had, because the Burgess Shale fossils of the Mid-Cambrian period contained a host of weird and wonderful forms that don't exist any more.

In Life's Grandeur he assures us that evolution does not lead to biological progress. In this, in fact, most modern biologists would agree with him but for the wrong reasons. Many, like Gould, have reacted too impetuously to late 19th-century bullishness. Thus, in the years after Darwin, many biologists and philosophers (but not Darwin himself!) tried to argue that natural selection was bound to produce super-intelligent creatures like us, since intelligence is sure to be advantageous. They went on to argue that human beings are superior to other creatures because we are "more highly evolved"; and suggested that some subsections of the human species - races - are superior to others for the same reasons. Finally, they suggested, such superior creatures have a "right" to rule over the others. Thus, under the borrowed cloak of Darwinian theory, they re-invented Genesis in its least attractive and most authoritarian mode.

Gould is quite right to expose such junk, and did so many years ago in The Mismeasure of Man. But we should not throw out intriguing babies with sullied bathwater nor replace 19th-century metaphysics with 20th-century political correctness. For the crude post-Darwinians made three mistakes Gould does not clearly spell out; and he falls into fresh errors of his own. First, their science was bad; so, for example, there is no biological reason to suggest that any human race is superior to any other. Equally mistakenly, they conflated "progress" with "destiny", and argued that the presence of any superior-seeming life form was somehow inevitable. Third, they conflated biological progress with moral advance, which is bad philosophy. As G. E. Moore later pointed out, what is "right" cannot simply be inferred from what is "natural". So the idea of evolutionary progress has been perverted, but if we reject it out of hand we will miss some very important insights.

To provide himself with a windmill at which to tilt, Gould first tells us that "we" are "driven to view evolution's thrust as predictable and progressive in order to place a positive spin upon geology's most frightening fact - the restriction of human existence to the last sliver of earthly time". Is that frightening? Really? Spiders, perhaps, if their legs are too long, but old rocks? But let us suspend incredulity and see where he is leading us. It is to tell us that we define progress according to criteria that are "obviously concocted, if we would only be honest and introspective enough about our motives, to place Homo sapiens atop a supposed heap."

Even Gould has to admit that this is a bit strong, for not everyone accepts "the maximally simplistic account of a single [evolutionary] ladder, with humans on top". On behalf of the half dozen or so who do, Gould assures us that Homo sapiens in practice occupies just one twiglet on an "floridly arborescent" evolutionary tree, that there is nothing about us or any other creature to justify any thought of progress, and that indeed there are no evolutionary "trends" by which such progress might be gauged. In fact, we are evolutionary dead-ends and general washouts, and would treat other creatures with more respect if only we realised this.

Well, I certainly support Gould's conclusions that we should treat our fellow creatures better. But the argument that leads him there is simply an exercise in schoolmanship, of the kind that 12th-century abbots used to dazzle unruly acolytes. First, Gould castigates Victorian metaphysics not with biology, but with a metaphysics of his own by appealing to the slippery concepts of dominance and success. Then - a neat piece of tautology - he defines success in a way that makes his argument irrefutable. Thus he equates "successful" with "numerous" so that creatures like us or peregrines or elephants must always rank below bacteria because there are so many more of them. And I thought it was because bacteria are smaller, which gives them more room.

But if we argue that a scientist should appeal to what is measurable, and if we do as every philosopher should and compare like with like, then trends, and progress, come roaring through the evolutionary tree. In lineage after lineage, creatures become measurably better at what they do as the generations pass. Any engineer can see that modern fish swim better than ancient fish. Their skeletons are lighter and more flexible, the bone is where it needs to be, and there are more places to attach a more intricate array of muscles. Furthermore, lineage after lineage - mackerel, herring salmon, tunny - independently developed these refinements. Similarly, pigeons, peregrines, swallows and albatrosses independently improved, measurably and unequivocally, on the flying skills of Archaeopteryx. Each line shows progress, objectively measurable by the people - engineers - who have the clearest view of what progress means.

To be sure, no Cambrian era zoologist could have predicted that we, Homo sapiens, would come on the scene 500 million years later, or that any creature would develop our particular brands of consciousness and language. Evolution does depend to a large extent on time and chance, so we can't predict any particular outcome. But the lack of such precision does not imply an absence of trends. That sentience would develop in some life form was absolutely on the cards.

Life itself was always likely, and is probably common throughout the universe. Early living slime was always liable to divide into discrete organisms. Organisms were always likely to separate ecologically into autotrophs, which feed themselves like plants, and heterotrophs, which eat autotrophs as animals do. Autotropy and heterotrophy each evolved many times on earth, in scores of lineages.

Heterotrophs can feed more efficiently if they are sentient - and sentience has also evolved many times. And sentience is always liable to upgrade into mental processing, as octopuses, insects, and vertebrates independently demonstrate. Among vertebrates, mammals' intelligence generally has a more flexible quality than birds'; and among mammals, porpoises, monkeys, squirrels, pigs and dogs independently evolved impressive intelligence from the small-brained mammalian ancestor that they shared about 85 million years ago. If group after group independently pursue the same line then we can infer a trend, especially if we can find very good reasons why such a trend should have been favoured.

To argue, as Gould does, that there is no such trend because the majority of creatures - that is, bacteria - did not grow more intelligent is sophistry and sleight of hand. Bacteria did not have the option of intelligence and neither would natural selection have favoured them if they had, for an introspective salmonella would lose out to one that focused on the more immediate task of decomposition.

The fact that bacteria did not become extinct when clever mammals appeared has nothing to do with the case. The two categories of creature occupy different niches and rarely compete directly. Significantly, the small- brained mammals which are obliged to compete with brainy ones have largely gone by the board except when they occupy very special niches - like koalas or moles.

In short, when you look at nature objectively you do see progress in lineage after lineage. You see definite trends that do not represent simply an adaptation to a particular niche but a more general response to the universal problems of gravity, behavioural flexibility and so on.

No one lineage was destined to give rise to Homo sapiens, but it would always be on the cards that some creature would develop some kind of intelligence, and many have done so. To argue otherwise is to erect a metaphysics that may be more PC than that of the imperial Victorians, but is still no more acceptable. Life's Grandeur, like Wonderful Life, is obfuscation. Life is indeed both wonderful and grand, but it is still too short for such stuff.