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THE WAY OF SCIENCE

Finding TRUTH AND MEANING in a Scientific Worldview

Prometheus Books

CHAPTER 1

THE DISSENT OF MAN

Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever or whatever abysses nature leads, or you will learn nothing.

—Thomas H. Huxley, letter of reply to Charles Kingsley (September 23, 1860)

When you stop to think about it, the enormous body of knowledge that we humans have come to appreciate in our brief stint on this planet is really quite remarkable. Our species, Homo sapiens, having branched from our hominid lineage a mere two thousand centuries ago, has far outstripped the cognitive capacity of every other earthly life form that has ever existed. We alone have come to understand the immensity of the universe, the workings of the stars and planets, and the forces that drive the seasons and turn night into day. Only humankind has managed to grasp the nature of the elements, the unity of matter and energy, the activities of the cell, and the function of the heart. These and countless other insights have, through the power of observation and reason, all become the exclusive province of the human mind.

Even more impressive is the stunning rapidity with which so many of nature's secrets have yielded to the ceaseless probings of humanity. Cave paintings and archaeological artifacts aside, the whole of recorded human history spans a surprisingly short period of time—fewer than five thousand years. And yet the vast majority of human knowledge has accumulated over an era much briefer still; a nascent epoch measured in mere centuries. Indeed, practically everything we've come to know about the natural world can be traced to the Renaissance and the formal adoption of what is now known as the scientific method. This objective approach to scientific inquiry, freed from the age-old compulsion to reconcile observation with preconceived worldviews, led quickly to the dissolution of numerous long-established and firmly entrenched beliefs that had effectively stymied scientific progress for nearly two thousand years. Chief among these doctrines were the geocentric astronomical system of Ptolemy and the Aristotelian conception of gravity and motion. Once these tenacious tenets were finally dispatched in the sixteenth century by the likes of Copernicus, Kepler, and Galileo, the flood gates were opened. As suddenly as the dropping of Sir Isaac's apple, the modern era of free scientific inquiry and technological advancement had begun, promising to elevate humankind to heights scarcely imagined—perhaps even to know the mind of God.

As one discovery led inexorably to the next, however, the underlying assumptions that had buttressed our ancestors' views of creation since time immemorial came increasingly into doubt, creating a surge of societal angst that lingers to this day. Being plucked from our celebrated position at the center of the universe was bad enough, but then to suffer the indignity of evolution! The irony was piercing. It seemed the more enlightened we became, the more sanctified by intellect and reason, the further our status as unique, eternal beings was undermined. Could it be that man, in truth, was simply the latest in a long line of ephemeral animal species culled from the primordial seas by the forces of natural selection? Was it really possible that human beings, who had come to dominate the Earth and its creatures so completely, were actually related to these beasts?

To most people of the Victorian era this notion seemed perfectly absurd and, as such, was summarily dismissed as the idle ruminations of the academic fringe. To the scientific community, however, the body of evidence unearthed by the diggings of one Charles Darwin was not so easily ignored. Indeed, the voluminous observations that Darwin amassed in his 1859 opus The Origin of Species had clearly provided the best evidence to date that life in all its complexity had evolved from simpler forms and that the forces of change were still at work. But that was the least of it. What really caused scientists to sit up and take notice was that Darwin had for the first time tied the evolutionary process to a scientifically viable mechanism of biological adaptation—something he called "descent with modification."

DARWIN'S DANGEROUS IDEA

Though the implications of Darwin's thesis were both provocative and far reaching, The Origin of Species might have emerged largely unnoticed beyond the cloistered walls of academia had its author not already published a popular tome on his Journal of Researches some two decades earlier. As it was, word that Darwin was finally ready to publish his "big book on species" created something of a stir among the English book-buying public ... so much so, in fact, that the original printing of 1,250 copies sold out to booksellers in a single day. Despite its popular appeal, however—or perhaps because of it—a massive groundswell of resistance had already begun to take shape by the time the second edition was released just six weeks later. If Darwin had hoped to forestall his detractors with a surfeit of supporting evidence, he could harbor the fantasy no longer. The theory of evolution by means of natural selection, no matter how logical in construct or well supported by physical proof, was not about to go unchallenged.

Predictably, it was the clergy who spearheaded the backlash of opposition. But theirs were not the only voices raised in protest. Joining in the chorus were a goodly number of scientists who, for reasons known only to God, felt obliged to defend the long-standing supposition that all life forms had been created de novo in their present form. But to be fair, even the unchurched had every reason to be skeptical at first. After all, in the 2,500-year-history of Western philosophical thought, the fixity of species had scarcely been questioned, much less seriously challenged. Like begets like, that was the natural order among all living things. People beget people, swine beget swine, and tulips beget tulips—it was that obvious. And besides, unlike the ministerial dictates on celestial mechanics that had long stood in opposition to astronomical observations, there had never been a compelling reason to doubt the teachings of the church in this regard. No one, for example, had ever witnessed a cow begetting anything but another cow, and chicken eggs, when they hatched, never yielded anything apart from a chick. But perhaps more importantly, the idea of a perfect and unchanging natural world had, by Darwin's time, become more than just a provincial belief borne of cultural norms. It had also gained a large measure of scientific legitimacy, thanks to the 1735 publication of Systema Naturae, a seminal treatise on natural order in which Swedish botanist Carl Linnaeus introduced his scheme for classifying organisms according to their physical similarities, a scientific discipline known nowadays as taxonomy.

The Linnaean system, still the basis for most taxonomic classifications used in biology today, was created under the explicit assumption that each class, order, family, and species of animal and plant in existence had remained unaltered since the world was new. Although the facts now speak strongly against this hypothesis, from a scientific perspective this was a perfectly legitimate place for the young Linnaeus to start, given the dearth of paleontologic (fossil) evidence at his disposal and the complete lack of genetic, embryologic, and biochemical clues available at the time. All in all, it was the kind of mistake that good scientists make all the time, and like all good scientists Linnaeus was not opposed to amending his hypotheses in deference to newfound facts. Indeed, as more information slowly came to light, Carl von Linné (as he would later come to be known) would ultimately abandon his original contention that species were fixed and would conclude instead that some—if not most—species had arisen after the creation of the world through the process of hybridization. He was, after all, the first to propose that whales be grouped with cows, mice, and other quadrupeds. Still, as the son of a Lutheran minister, there were certain ideological lines that Linnaeus was not prepared to cross; time-honored beliefs that would ultimately blind him to the possibility that these changes might, in fact, be an open-ended process devoid of divine direction.

But while Linnaeus's work did cast a long shadow over all those who followed in his wake, Darwin's dilemma did not stem from just one man's narrow interpretation of an incomplete dataset. Linnaeus had simply advanced what Darwin had reason to believe was a false hypothesis, and the dissolution of false hypotheses is what ultimately pushes scientific knowledge forward. Linnaeus had done his part and Darwin was doing his, just as scientists were supposed to do. The problem was, the immutability of species was no ordinary hypothesis. This was a scientific paradigm with biblical backing; a theory that people very much wanted to believe. Thus, contrary to the base principles of scientific inquiry, the "fixity of species" hypothesis had in the minds of many come to assume the mantle of essential truth—an unassailable tenet that stood beyond all questioning. As a consequence, Darwin found himself not merely challenging a long-standing scientific conjecture but casting doubt upon a cherished article of faith. Pressing ahead meant that he would have to tread lightly and have plenty of proof to back his claims.

As Darwin prepared to publish his thesis, he was very much aware of the maelstrom he was about to unleash, this despite the fact that biological evolution was an idea that had already been bandied about for quite some time. The Greek philosopher Anaximander of Miletus (610–545 BCE) was among the first to broach the subject, having deduced, quite correctly, that humans had evolved from fishlike aquatic creatures that had somehow adapted to life on dry land. For reasons lost to history, however, his proposal never grew legs and was all but forgotten until the Italian Renaissance when philosopher Lucilio Vanini finally revived the notion of human evolution in 1616, suggesting that humans descended from apes. Unfortunately, the revival was short-lived, as the outspoken theorist was burned as a heretic just three years later. Still, despite this discomfiting reception, speculation concerning the evolution of species persisted and was widely discussed—albeit discreetly—in scientific circles even as a young Charles Darwin set sail as an unpaid naturalist on the British survey ship H.M.S. Beagle in December of 1831.

Upon his return to England, Darwin's five years of field work studying the flora and fauna of Africa, South America, and the Galápagos archipelago quickly coalesced into a singular insight of immense importance: namely, that natural selection was the driving force behind the evolution of all living things. It finally made sense: a random variant within a population would, in time, become more prevalent if environmental conditions were to favor that particular characteristic. An elongation of the beak, a thickening of the fur, a flap of skin tucked between the toes, a bony protuberance here and there: just about any arbitrary nonconformity could do the trick under the right circumstances. Even the slightest competitive advantage might act to enhance survival, yield more offspring, and increase the prevalence of a particular trait among individuals of a species. And once a population had changed enough to become reproductively isolated from its progenitors, taxonomists would come to recognize these individuals as members of a new and separate species, similar yet distinct. String enough of these speciation events together and only the faintest similarities would survive from one end of the chain to the other; a situation that, in the prescientific era, provided the perfect pretext for humans to distance themselves from their animal kin.

At last, a self-consistent explanation for the evolution of species had been pieced together from the shards of evidence available to pre-genomic scientists. But was the public ready to hear it? Reaction to the publication of Vestiges of the Natural History of Creation in 1844 suggested to Darwin that they might not be. Indeed, just as he was putting the finishing touches on a detailed sketch of his thesis, Vestiges author Robert Chambers had unwittingly given Darwin a sobering glimpse at the kind of reception his ideas were likely to receive. And it was quite an eyeful. Darwin could hardly help but notice the vitriol that Chambers had inspired with his suggestion that the Earth and its inhabitants had not been created all at once but had instead evolved gradually through a vast sequence of incremental changes. Although the author had cited evidence both copious and credible to support his conclusions, the idea that the creation process had taken considerably longer than biblical literalists had assumed did not play well with traditionalist thinkers. But this was nothing compared to the righteous indignation that greeted Chambers's proposition that humankind had, on a geological time scale, emerged quite recently as a transmutation of the great apes. Many people had taken this final assertion as a personal affront and were not shy about voicing their displeasure. Fortunately, these were gentler times and no one had sought to put the author's feet to the fire—at least not in the literal sense.

Still, it was easy to see why Chambers had chosen to publish Vestiges anonymously. It had taken more than a dozen generations for people to fully digest the idea of an itinerant Earth circumnavigating its parent star, and by all indications most folks had little appetite for a second course of scientific revelation, especially one so unpalatable as the evolution of species. So despite having a 231-page treatise already in hand—a landmark essay that explained how natural selection might act to cull new species from existing varieties—Darwin hesitated. For better or worse the stormy politics of evolution had stayed his hand, redoubling his want to test every aspect of natural selection to the greatest possible extent before releasing his findings to a vexed and volatile public. This combination of diligence and trepidation had proved so viscous a mix, in fact, that it would ultimately prevent Darwin from publishing his theory for another fifteen years. Until, that is, he received a parcel from Alfred Russel Wallace.

GREAT MINDS ...

For ten years prior, Wallace had worked in the Amazon and Malay archipelago as a collector of exotic specimens for European buyers and in the course of his travels had ample opportunity to study the stunning variety of flora and fauna to be found there. He, like Darwin, had harbored a long-standing interest in the causes of organic evolution and had surmised in a sudden flash of recognition that the proliferation of plants and animals might very well operate under principles that parallel the economic checks and balances described by Thomas Malthus in his Essay on the Principle of Population (1798). Like a bolt out of the blue, both men were struck by Malthus's observation that plants and animals naturally produce far more offspring than can possibly survive and thus create intense competition among siblings for limited resources. This singular insight, in concert with emerging geological evidence that spoke to the immense age of the Earth, raised the prospect that the tremendous diversity of modern species might, in fact, be the residue of innumerous varieties struggling over untold eons to survive amid shifting environmental conditions.

Excited over his breakthrough, which had come to him in dramatic fashion during a two-week bout with malaria, Wallace wasted little time. As soon as he was well enough, Wallace penned a brief essay on what he called the "progression and continued divergence of varieties from their parent species" and sent it off to Darwin, a man he knew through prior correspondence to be interested in "the species question." With it he included a brief note asking Darwin to review the manuscript and, if he thought it worthy, forward it to Charles Lyell, whose Principles of Geology had also figured prominently in his thinking.

Darwin was stunned. Wallace had summarized his 1844 essay with such precision that he could scarcely imagine writing a better outline himself. The similarities were indeed uncanny, and though on some level Darwin must have been pleased to receive so clear an affirmation of his secreted theory, he was understandably pained to surrender ownership of his life's work and agonized over what to do next. True to his patrician upbringing, Darwin's first impulse was to stand aside and cede priority to Wallace, who, despite having started a distant second, was obviously prepared to publish first. On the other hand, Charles Lyell and botanist Joseph Hooker had for years urged Darwin to make public a sketch of his original essay and were resolute in their insistence that Darwin should now issue an abstract of his own to preserve the precedence that was rightfully his. Still, Darwin worried that doing so might seem petty and underhanded given the circumstances, writing to Lyell in a letter dated June 25: "I shd be extremely glad now to publish a sketch of my general views in about a dozen pages or so. But I cannot persuade myself that I can do so honorably.... I would far rather burn my whole book than that he or any man shd think that I had behaved in a paltry spirit."

For Darwin, however, the issue of precedence would soon be eclipsed by more pressing concerns, as his infant son Charles—not yet nineteen months old—had recently taken ill with scarlet fever and was growing sicker by the day. Knowing that several children in the village of Downe had already died in the wake of the contagion, Darwin was consumed with worry and could think of little else, confessing to Hooker that under the circumstances it was "miserable in [him] to care at all about priority." Conflicted and heartsick, Darwin soon lost all interest in what now seemed to him a trifling affair and was content to have his "two best & kindest friends" settle the matter in whatever way they thought fair.
(Continues...)

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Excerpted from THE WAY OF SCIENCE by DENNIS R. TRUMBLE. Copyright © 2013 Dennis R. Trumble. Excerpted by permission of Prometheus Books.
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