“We have a hunger of the mind which asks for knowledge of all around us, and the more we gain, the more is our desire,” trailblazing astronomer Maria Mitchell observed in contemplating science, religion, and our conquest of truth at the end of the nineteenth century. “If we ever reach the point where we think we thoroughly understand who we are and where we came from, we will have failed,” Carl Sagan wrote a century later in his exquisite meditation on science and spirituality. And yet the longing for stable answers and thorough understanding — or, as Hannah Arendt memorably framed it, the propensity for asking unanswerable questions — might be one of the hallmarks of our species. After all, for as long as modern science has existed, scientists have attempted to answer such unanswerable questions by trying to either reconcile science and religion, like Galileo did in defending his theories against the Inquisition and Ada Lovelace did in considering the interconnectedness of the universe, or at least to relegate them to different realms of inquiry.

Adding to the canon of these meditations is the celebrated English cosmologist and astrophysicist Sir Martin Rees — the last European court astronomer in his position as Astronomer Royal to the House of Windsor and science adviser to the Queen of England.

In We Are All Stardust: Leading Scientists Talk About Their Work, Their Lives, and the Mysteries of Our Existence (public library) — Austrian physicist, essayist, and science journalist Stefan Klein’s fantastic compendium of interviews, which also gave us Nobel-winning physicist Steven Weinberg on simplicity, complexity, and the unity of the universe — Rees reflects on his rather unusual entry point into the question of science and spirituality:

I was brought up as a member of the Church of England and simply follow the customs of my tribe. The church is part of my culture; I like the rituals and the music. If I had grown up in Iraq, I would go to a mosque… It seems to me that people who attack religion don’t really understand it. Science and religion can coexist peacefully — although I don’t think they have much to say to each other. What I would like best would be for scientists not even to use the word “God.” … Fundamental physics shows how hard it is for us to grasp even the simplest things in the world. That makes you quite skeptical whenever someone declares he has the key to some deeper reality… I know that we don’t yet even understand the hydrogen atom — so how could I believe in dogmas? I’m a practicing Christian, but not a believing one.

The central problem of religious dogma, of course, is that the mythology of “God” offers a single cohesive story that contends to explain all of “Creation” — a theory that claims its truthfulness not by empirical evidence but by insistent assertion. In a sentiment that calls to mind Sagan’s abiding wisdom on the vital balance between skepticism and openness, Rees illustrates how the scientist regards a theory:

I find it irrational to become attached to one theory. I prefer to let different ideas compete like horses in a race and watch which one wins.

When asked whether he believes that scientists make more intelligent decisions as citizens, Rees responds:

[Scientists] bring a special perspective to things. For example, as an astrophysicist, I’m used to thinking in terms of extremely long periods of time. For many people, the year 2050 is distant enough to seem unimaginably far away. I, however, am constantly aware that we’re the result of four billion years of evolution — and that the future of the earth will last at least as long. When you always have in mind how many generations might follow us, you take a different attitude toward many questions of the present. You realize how much is at stake.

With an eye to the progress and peril that human civilization has wrought, Rees considers the prospective evolutionary future of a post-human intelligence:

We humans of the present are certainly not the summit of Creation. Species more intelligent than us will inhabit the earth. They might even appear quite soon. These days evolution is no longer driven by slow natural development, as Darwin described it, but by human culture. So a post-human intelligence might be made by us ourselves. And I hope that our successors have a better understanding of the world.

Complement this particular portion of the thoroughly invigorating We Are All Stardust — which includes conversations with such titans of science as primatologist Jane Goodall, evolutionary biologist Richard Dawkins, and geographer Jared Diamond — with Freeman Dyson on the unanswerable questions that give meaning to the universe, Simone de Beauvoir on the spiritual rewards of atheism, and Alan Lightman’s poetic ode to science and the unknown.