An edgy biography of Stephen Hawking has me reminiscing about science’s good old days. Or were they bad? I can’t decide. I’m talking about the 1990s, when scientific hubris ran rampant. As journalist Charles Seife recalls in Hawking Hawking: The Selling of a Scientific Celebrity, Hawking and other physicists convinced us that they were on the verge of a “theory of everything” that would solve the riddle of existence. It would reveal why there is something rather than nothing, and why that something is the way it is.

In this column, I’ll look at an equally ambitious and closely related claim, that science will absorb other ways of seeing the world, including the arts, humanities and religion. Nonscientific modes of knowledge won’t necessarily vanish, but they will become consistent with science, our supreme source of truth. The most eloquent advocate of this perspective is biologist Edward Wilson, one of our greatest scientist-writers.

In his 1998 bestseller Consilience: The Unity of Knowledge, Wilson prophesies that science will soon yield such a compelling, complete theory of nature, including human nature, that “the humanities, ranging from philosophy and history to moral reasoning, comparative religion, and interpretation of the arts, will draw closer to the sciences and partly fuse with them.” Wilson calls this unification of knowledge “consilience,” an old-fashioned term for coming together or converging. Consilience will resolve our age-old identity crisis, helping us understand once and for all “who we are and why we are here,” as Wilson puts it.

Dismissing philosophers’ warnings against deriving “ought” from “is,” Wilson insists that we can deduce moral principles from science. Science can illuminate our moral impulses and emotions, such as our love for those who share our genes, as well as giving us moral guidance. This linkage of science to ethics is crucial, because Wilson wants us to share his desire to preserve nature in all its wild variety, a goal that he views as an ethical imperative.

At first glance you might wonder: Who could possibly object to this vision? Wouldn’t we all love to agree on a comprehensive worldview, consistent with science, that tells us how to behave individually and collectively? And in fact. many scholars share Wilson’s hope for a merger of science with alternative ways of engaging with reality. Some enthusiasts have formed the Consilience Project, dedicated to “developing a body of social theory and analysis that explains and seeks solutions to the unique challenges we face today.” Last year, poet-novelist Clint Margrave wrote an eloquent defense of consilience for Quillette, noting that he has “often drawn inspiration from science.”

Another consilience booster is psychologist and megapundit Steven Pinker, who praised Wilson’s “excellent” book in 1998 and calls for consilience between science and the humanities in his 2018 bestseller Enlightenment Now. The major difference between Wilson and Pinker is stylistic. Whereas Wilson holds out an olive branch to “postmodern” humanities scholars who challenge science’s objectivity and authority, Pinker scolds them. Pinker accuses postmodernists of “defiant obscurantism, self-refuting relativism and suffocating political correctness.”

The enduring appeal of consilience makes it worth revisiting. Consilience raises two big questions: (1) Is it feasible? (2) Is it desirable? Feasibility first. As Wilson points out, physics has been an especially potent unifier, establishing over the past few centuries that the heavens and earth are made of the same stuff ruled by the same forces. Now physicists seek a single theory that fuses general relativity, which describes gravity, with quantum field theory, which accounts for electromagnetism and the nuclear forces. This is Hawking’s theory of everything and Steven Weinberg’s “final theory."

Writing in 1998, Wilson clearly expected physicists to find a theory of everything soon, but today they seem farther than ever from that goal. Worse, they still cannot agree on what quantum mechanics means. As science writer Philip Ball points out in his 2018 book Beyond Weird: Why Everything You Thought You Knew about Quantum Physics Is Different, there are more interpretations of quantum mechanics now than ever.

The same is true of scientific attempts to bridge the explanatory chasm between matter and mind. In the 1990s, it still seemed possible that researchers would discover how physical processes in the brain and other systems generate consciousness. Since then, mind-body studies have undergone a paradigm explosion, with theorists espousing a bewildering variety of models, involving quantum mechanics, information theory and Bayesian mathematics.  Some researchers suggest that consciousness pervades all matter, a view called panpsychism; others insist that the so-called hard problem of consciousness is a pseudoproblem because consciousness is an “illusion.”

There are schisms even within Wilson’s own field of evolutionary biology. In Consilience and elsewhere, Wilson suggests that natural selection promotes traits at the level of tribes and other groups; in this way, evolution might have bequeathed us a propensity for religion, war and other social behaviors. Other prominent Darwinians, notably Richard Dawkins and Robert Trivers, reject group selection, arguing that natural selection operates only at the level of individual organisms and even individual genes.

If scientists cannot achieve consilience even within specific fields, what hope is there for consilience between, say, quantum chromodynamics and queer theory? (Actually, in her fascinating 2007 book Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning, physicist-philosopher Karen Barad finds resonances between physics and gender politics; but Barad’s book represents the kind of postmodern analysis deplored by Wilson and Pinker.) If consilience entails convergence toward a consensus, science is moving away from consilience.

So, consilience doesn’t look feasible, at least not at the moment. Next question: Is consilience desirable? Although I’ve always doubted whether it could happen, I once thought consilience should happen. If humanity can agree on a single, rational worldview, maybe we can do a better job solving our shared problems, like climate change, inequality, pandemics and militarism. We could also get rid of bad ideas, such as the notion that God likes some of us more than others; or that racial and sexual inequality and war are inevitable consequences of our biology.

I also saw theoretical diversity, or pluralism, as philosophers call it, as a symptom of failure; the abundance of “solutions” to the mind-body problem, like the abundance of treatments for cancer, means that none works very well. But increasingly, I see pluralism as a valuable, even necessary counterweight to our yearning for certitude. Pluralism is especially important when it comes to our ideas about who we are, can be and should be. If we settle on a single self-conception, we risk limiting our freedom to reinvent ourselves, to discover new ways to flourish.

Wilson acknowledges that consilience is a reductionistic enterprise, which will eliminate many ways of seeing the world. Consider how he treats mystical visions, in which we seem to glimpse truths normally hidden behind the surface of things. To my mind, these experiences rub our faces in the unutterable weirdness of existence, which transcends all our knowledge and forms of expression. As William James says in The Varieties of Religious Experience, mystical experiences should “forbid a premature closing of our accounts with reality.”

Wilson disagrees. He thinks mystical experiences are reducible to physiological processes. In Consilience, he focuses on Peruvian shaman-artist Pablo Amaringo, whose paintings depict fantastical, jungly visions induced by ayahuasca, a hallucinogenic tea (which I happen to have taken) brewed from two Amazonian plants. Wilson attributes the snakes that slither through Amaringo’s paintings to natural selection, which instilled an adaptive fear of snakes in our ancestors; it should not be surprising that snakes populate many religious myths, such as the biblical story of Eden.

Moreover, ayahuasca contains psychotropic compounds, including the potent psychedelic dimethyltryptamine, like those that induce dreams, which stem from, in Wilson’s words, the “editing of information in the memory banks of the brain” that occurs while we sleep. These nightly neural discharges are “arbitrary in content,” that is, meaningless; but the brain desperately tries to assemble them into “coherent narratives,” which we experience as dreams.

In this way, Wilson “explains” Amaringo’s visions in terms of evolutionary biology, psychology and neurochemistry. This is a spectacular example of what Paul Feyerabend, my favorite philosopher and a fierce advocate for pluralism, calls “the tyranny of truth.” Wilson imposes his materialistic, secular worldview on the shaman, and he strips ayahuasca visions of any genuine spiritual significance. While he exalts biological diversity, Wilson shows little respect for the diversity of human beliefs.

Wilson is a gracious, courtly man in person as well on the page. But his consilience project stems from excessive faith in science, or scientism. (Both Wilson and Pinker embrace the term scientism, and they no doubt think that the phrase “excessive faith in science” is oxymoronic.) Given the failure to achieve consilience within physics and biology—not to mention the replication crisis and other problems—scientists should stop indulging in fantasies about conquering all human culture and attaining something akin to omniscience. Scientists, in short, should be more humble.

Ironically, Wilson himself questioned the desirability of final knowledge early in his career. At the end of his 1975 masterpiece Sociobiology, Wilson anticipates the themes of Consilience, predicting that evolutionary theory plus genetics will soon absorb the social sciences and humanities. But Wilson doesn’t exult at this prospect. When we can explain ourselves in “mechanistic terms,” he warns, “the result might be hard to accept”; we might find ourselves, as Camus put it, “divested of illusions.”

Wilson needn’t have worried. Scientific omniscience looks less likely than ever, and humans are far too diverse, creative and contrary to settle for a single worldview of any kind. Inspired by mysticism and the arts, as well as by science, we will keep arguing about who we are and reinventing ourselves forever. Is consilience a bad idea, which we’d be better off without? I wouldn’t go that far. Like utopia, another byproduct of our yearning for perfection, consilience, the dream of total knowledge, can serve as a useful goad to the imagination, as long as we see it as an unreachable ideal. Let’s just hope we never think we’ve reached it.

This is an opinion and analysis article; the views expressed by the author or authors are not necessarily those of Scientific American.

Further Reading:

The Delusion of Scientific Omniscience

The End of Science (updated 2015 edition)

Mind-Body Problems: Science, Subjectivity and Who We Really Are

I just talked about consilience with science journalist Philip Ball on my podcast “Mind-Body Problems.”

I brood over the limits of knowledge in my new book Pay Attention: Sex, Death, and Science.