Whether or not scientists are from Mars and humanists from Venus, the “two cultures” debate about the arts and sciences has never been down to earth. For decades we’ve endured schematic sparring between straw men: humanists claim that scientists are reductive, scientists find humanists reactionary. (A recent bout between the cognitive scientist Steven Pinker and the literary critic Leon Wieseltier in the pages of The New Republic ran true to form.) Marcelo Gleiser, a physicist with strong ties to the humanities, is alarmed by the hubristic stance of his discipline and the backlash it is liable to provoke. He has written The Island of Knowledge as “a much needed self-analysis in a time when scientific speculation and arrogance are rampant…. I am attempting to protect science from attacks on its intellectual integrity.”

Perhaps this well-meant intervention is unnecessary, given the many signs of interdisciplinary concord today. These include the growth of science studies, technocultural studies and the digital humanities within the liberal arts; successful popularizations of science in the media—the new Cosmos had the largest debut of any series in television history; and the ongoing enthusiasm for science fiction in mass culture. (True, the genre is often light-years away from genuine science, but at its best it’s an exemplary merger of the two cultures.) From such portents alone, we seem poised to embrace the ideal of “one culture, many methods.” But might this be a pious platitude, if not a colossal category mistake? Are the arts and sciences actually fated to be an estranged couple, burdening their offspring with crippling complexes?

Gleiser hopes to heal the rift between the two cultures by denying the scientific dream of establishing final truths. He insists that while the arts and sciences have different methods, they are fundamentally united in their search for humanity’s roots and purposes; they also share the human limitation of finding only provisional and incomplete answers. He traces Western science’s misguided aspiration to omniscience, and its consequent devaluing of human fallibility, to its beginnings in classical Greece. This is certainly an appropriate place to start for a history of science’s Platonic aspirations. However, the origin of the “two cultures” debate that Gleiser implicitly addresses is more recent, and thus less entrenched, than his own chronology implies. The unhappy couple stands a good chance of being reconciled through judicious interventions such as his.

Their current disaffection commenced in the early nineteenth century, when the “natural philosopher,” a man of parts, began to be replaced by the specialized “scientist,” a term coined in the 1830s. A new division of labor emerged. Scientists claimed to establish objective facts and laws about the natural world by stifling their imagination and relying on empirical observation, testing and prediction; humanists embraced the Romantic imagination, interpreting the ambiguous nature of human experience through empathy as well as analysis. At the dawn of the twentieth century, reconciliation beckoned within the new domain of the “social sciences.” Economists, anthropologists, sociologists, psychologists and historians combined rational inquiry with intuitive insight—the sort of “scientific use of the imagination” proposed by the scientist John Tyndall and exemplified by the fictional icon Sherlock Holmes. Nevertheless, methods clashed and philosophies jostled. Should social scientists seek simple, encompassing laws like the natural sciences, or should they highlight particularity and uniqueness, like the humanities? The debate revolved around approaches deemed “nomothetic” (generalizing) or ”idiographic” (individualizing)—terms so ugly they assured public disinterest.

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The battle lines became firmly drawn in the years following World War II. In Science and Human Values (1956), Jacob Bronowski attempted to overcome the sullen suspicions between humanists and scientists, each now condemning the other for the horrifying misuse of technology during the conflict:

Those whose education and perhaps tastes have confined them to the humanities protest that the scientists alone are to blame, for plainly no mandarin ever made a bomb or an industry. The scientists say, with equal contempt, that the Greek scholars and the earnest explorers of cave paintings do well to wash their hands of blame; but what in fact are they doing to help direct the society whose ills grow more often from inaction than from error?

Bronowski was a published poet and biographer of William Blake as well as a mathematician; he knew that artists and scientists had different aims and methods. Yet he also attested that both engaged in imaginative explorations of the unities underlying the human and natural worlds.

If Bronowski’s stress on the imagination as the foundation of both the arts and sciences had prevailed, Gleiser would not need to remind his readers that Newton and Einstein shared a similar “belief in the creative process.” However, while Bronowski meant to heal the breach by exposing it, he inadvertently encouraged others to expand it into an unbridgeable gulf, a quagmire of stalemate and trench warfare. His friend C.P. Snow battened on the division in lectures that were subsequently published under the meme-friendly title The Two Cultures and the Scientific Revolution (1959). Snow acknowledged that scientists could be philistine about the humanities, but his ire was directed at the humanists: they composed the governing establishment, their willful ignorance about science impeding policies that could help millions worldwide. As the historian Guy Ortolano has shown in The Two Cultures Controversy (2009), Snow tactlessly insinuated that the literary intelligentsia’s delight in irrational modernism rather than rational science was partly responsible for the Holocaust: “Didn’t the influence of all they represent bring Auschwitz that much closer?” Such ad hominem attacks raised the hackles of the literary critic F.R. Leavis, himself a master of the art. His response, Two Cultures? The Significance of C.P. Snow (1962), proved only that humanists could be just as intemperate as Snow implied. (One critic, appalled by Leavis’s vituperation, dubbed him “the Himmler of Literature.”)

The “two cultures” debate has continued for decades, often rehashing the same issues and generating more heat than light—a metaphor that reminds us of how entwined the arts and sciences are in everyday life. In recent years, however, the tone and substance of the debate have changed. There is a revived tenor of nineteenth-century scientific triumphalism, owing in part to the amazing successes of the natural sciences, from the standard model in physics to DNA sequencing and the Human Genome Project. Numerous physicists are convinced that they will discover a final “theory of everything” proving the unity of nature’s laws and defining its constituent elements. Not all scientists share this reductionist outlook, but the wider culture unintentionally reinforces it, thanks to information technology’s colonization of everyday life. We’re more primed than ever before to think in terms of keyword searches, algorithmic sequences and Big Data.

No wonder that science, for many, has become a secular holy writ, goading its believers to denounce all forms of religion as empty superstition while converting the humanistic disciplines into mere disciples of science. The new priesthood even performs last rites, as Stephen Hawking did in 2011: “Philosophy is dead,” he pronounced, because “[p]hilosophers have not kept up with modern developments in science. Particularly physics.” Gleiser is troubled by the fatuous preening of some prominent scientists, who risk alienating a public otherwise predisposed to appreciate the marvels of scientific discovery and the mysteries of scientific exploration: “To claim to know the ‘truth’ is too heavy a burden for scientists to carry. We learn from what we can measure and should be humbled by how much we can’t. It’s what we don’t know that matters.”

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In this polarized atmosphere, offers of a truce in the manner of Bronowski simply inflame mutual mistrust. The recent dust-up in The New Republic began when Pinker extended to the humanities an olive branch of sorts in the name of “consilience” with science. Wieseltier identified it as a cudgel, and in some ways he was right: Pinker began by transubstantiating eighteenth-century philosophers like Hume and Rousseau into scientists manqué, and then added insult to injury by suggesting that the humanities become more like the sciences by adopting a “progressive agenda.” Wieseltier agreed with him that the boundaries between the two cultures were porous, but demanded they be buttressed against science’s imperialistic agenda: “Unified field theories may turn scientists on, but they turn humanists off: it has taken a very long time to establish the epistemological humility, the pluralistic largeness of mind, that those borders represent, and no revolution in any science has the power to repeal it.” (To be fair, the humanities have had their share of unified theories, including Marxism, Freudianism and structuralism. The two cultures are true to human nature in craving essences and totalities; even some postmodernists have been heard to proclaim that there are absolutely no absolutes.)

If such well-intentioned partisans can’t negotiate a cease-fire, perhaps each side needs to conduct an internal audit about what it has in common with its opponent prior to future armistice talks. Philosophers and historians of science have laid the groundwork, but they tend to be humanists and thus easier for hard scientists to dismiss. Steven Weinberg, a Nobel laureate in physics, patronized the philosophy of science as providing a “pleasing gloss” on scientific achievements, but little more: “We should not expect it to provide today’s scientists with any useful guidance about how to go about their work or about what they are likely to find.”

This situation is what makes Gleiser’s intervention in the debates so timely and interesting. He started his career in theoretical physics believing in the holy grail of his field, a final theory unifying quantum mechanics with general relativity. In his autobiographical A Tear at the Edge of Creation (2010), he confessed that he had been attracted to science initially by his own psychological need for order in an apparently meaningless universe. The death of his mother when he was 6 led him to search for sources of transcendence, from religion to fantasy fiction. He finally became a convert to the secular “magic” of physics as a teenager: “Science was a rational connection to a reality beyond our senses. There was a bridge to the mysterious, and it did not have to cross over supernatural lands. This was the greatest realization of my life.”

Gleiser has never lost his sense of wonder about existence or about the importance of science in conveying it. But his own experiences as a professional have led him to abandon the dream of attaining any final theory—in fact, he views the goal itself as a form of “intellectual vanity” and “monotheistic science.” Part of his disillusion has to do with the failure to find possible tests or empirical evidence for the extravagant claims of superstring theory, rendering it closer to metaphysics than physics. Gleiser also immersed himself in the history of science and was reminded that Western science has dreamed of discovering ultimate truth since the discipline’s inception. This faith has never been substantiated at the empirical level, situating it alongside mythic and religious yearnings to attain “oneness.” “There are faith-based myths running deep in science’s canon,” he maintains. “Scientists, even the great ones, may confuse their expectations of reality with reality itself.”

None of these heartfelt observations would surprise philosophers of science; Mary Midgley’s wonderful Science as Salvation (1992)—not included in Gleiser’s bibliography—makes the same points. But Gleiser speaks as a scientist and is thus more likely to be heard by his peers—provided he doesn’t scare them off with his anti-realist stance. He can sound positively postmodern when he defines science as “a human construction, a narrative we create to make sense of the world around us.” But if he opposes the naïve realist belief that science accesses a mind-independent reality, he doesn’t make the equally naïve claim that science is merely a social construction. It does attain verifiable knowledge of reality, its evolving instruments yielding increasingly precise data: but the resultant explanations are inevitably partial and always subject to change. There are no final answers, for new knowledge yields new mysteries to be solved. Science is a limited, interpretive practice and will only be “humanized” if it adopts the epistemological humility that Wieseltier claimed was the purview of the humanities.

These conclusions, and some of the same historical examples, reappear in Gleiser’s The Island of Knowledge. In this work, he underscores the many limits, even “insurmountable barriers,” to scientific knowledge. He likens science to an island situated within a wider sea of the unknown: “As the Island of Knowledge grows, so do the shores of our ignorance.” In thirty-two brief chapters, he provides a stimulating overview of Western science’s shifting interpretations of reality from classical Greece to the present, including informative discussions of atomism, alchemy, classical physics, quantum mechanics, quantum entanglement, the Big Bang, the multiverse, superstring theory, mathematics, information theory, computers and consciousness.

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Gleiser is a brilliant expositor of difficult concepts, and his raw enthusiasm is transporting. He is equally fervent about the uncertainties of science, having once been a believer in its unalloyed truth: “I find myself in the difficult role of being a romantic having to kill the dreams of other romantics.” However, as with many disillusioned votaries of absolutist creeds, his new stance can be as fundamentalist as the one he rejects. As he argued in his previous book—and continues to argue in this one—science’s “essential limitations” include the imprecision of its instruments and the cultural contingency of its concepts. In The Island of Knowledge, he eagerly gathers other objections to any final theory as kindling for a bonfire of the vanities. He contends that nature itself posits absolute limits to what we can know empirically, such as the initial conditions that generated the Big Bang or the existence of multiple universes implied by current theories of cosmic inflation. In addition, the quantum world is impervious to deterministic explanations. And mathematics is likely not mind-independent but rather a human invention—one whose formal structures cannot be both consistent and complete.

These assertions may be valid—only time will tell, if that—but Gleiser’s temperamental absolutism sometimes subverts his pragmatic faith in an unfinished universe. He insists that “there are aspects of reality that are permanently beyond our reach,” and also that “we can never know for certain…. We should build solid arguments based on current scientific knowledge but keep our minds open for surprises.” He notes that some mysteries will always remain mysteries—“there is an essential difference between ‘we don’t know’ and ‘we can’t know’”—but also admits that “‘Never’ is a hard word to use in science.” He inadvertently becomes his own best example of how hard it is to practice epistemological humility even when one is committed to it. Attaining that outlook, rather than certainty, is the true noble dream.

It is this lesson, above all, that makes Gleiser’s intervention in the “two cultures” debate so valuable. As scientists, both he and Bronowski have established underlying unities: not in the forces of nature, but in the humanities and the sciences. Bronowski stressed their common reliance on imagination, which subtends “numbers and pictures, the lever and The Iliad, the shapes of atoms and the great plays and the Socratic dialogues.” Gleiser emphasizes science’s inherent limitations, which make it “more beautiful and powerful, not less.” Despite its commitment to establishing verifiable knowledge of reality, science remains an interpretive and contingent practice—indeed, a humanistic enterprise. In the “two cultures” debate, one hopes that Gleiser’s words are among the last, especially his claim that science aligns “with the rest of the human creative output—impressive, multifaceted, and imperfect as we are.”n