It was an enchanted 40 minutes, and utterly unexpected—one of those experiences that seems to illuminate one’s waking hours for days to follow.

 The day began mundanely enough, with the 4 a.m. ringing of the alarm clock. My wife and I had to drive an hour to catch a 6:55 a.m. flight from Omaha to Oakland. At Eppley Airfield, we endured the Southwest Airlines cattle call in the terminal, eventually found seats in the back part of a full plane—a middle seat was my fate—and headed for Las Vegas.

 The day improved noticeably when we landed briefly in Las Vegas. Nearly all the passengers got off the plane, and only a few walked on for the continuing flight to Oakland. Most people, it seems, fly to Vegas for the weekend, not from Vegas.

 Once we had regained 10,000 feet of altitude, I cued up Rachmaninoff’s Second Piano Concerto on my iPod, and began reading the next chapter in Dinesh D’Souza’s new book, What’s So Great About Christianity. D’Souza is the Rishwain Research Scholar in the Hoover Institution at Stanford University.

 The main point of the chapter is profound. “The greatest idea of modern science is based not on reason but on faith,” D’Souza writes. “[It] is the presumption, quite impossible to prove, that the universe is rational.”

 D’Souza goes on to demonstrate that there is no logical reason for the universe to be rational; it could just as well be utterly random. But scientists take the rationality of the universe for granted.

“Without the ‘irrational’ belief that we live in an ordered universe, modern science is impossible,” D’Souza writes. “So where did Western man get this faith in a unified, ordered, and accessible universe? . . . My answer, in a word, is Christianity.”

Well, you have to read more both before and after these brief quotations to grasp the full force of D’Souza’s argument, but it did get my mind spinning in a new direction.

About then, I looked up and realized that I could be sitting in any one of a couple dozen window seats. I also realized that we would be flying over the Sierra Nevada mountains before long. So I moved several rows back to a window behind the wing, facing southwest. The sky was clear, the Nevada desert was spread out below, and mountains were on the horizon. The piano concerto’s dreamy second movement was just beginning on my iPod.

 As the plane continued on its northwesterly route, the topography below commanded my attention. Treeless desert mountains, their creased and folded structure highlighted by the mid-morning November sun, presented a vast labyrinth of rugged ridges and gullies. Perfectly formed alluvial fans spread out into dry lake beds from the gullies’ mouths.

Not wanting to relinquish the ideal complement to nature’s spellbinding display unfolding below me, I set the iPod to replay the concerto’s contemplative second movement.

 Our route was now taking us over steep terrain. A dusting of autumn snow graced higher slopes. Heavy snow—probably a small glacier or two—came into view. Bald granite precipices tumbled from razor-edged ridges. Gemlike emerald lakes nestled between soaring peaks. The music again reached the transition point, and again I set it back.

 I tried to pick out a spot I might recognize from high Sierra backpacking trips with my kids years ago. A couple times I thought I might have identified a spot, but I was never sure—until I saw the canyon that begins at the headwaters of the Merced River, tumbles over Nevada Falls and Vernal Falls, and points the way to Yosemite Valley. Cloud’s Rest was in full view—so was Half Dome, and the sheer granite face past which Yosemite Falls thunders in springtime. The 3,000-foot vertical rise of El Capitan reared up a bit farther west. To the north, Hetch Hetchy Valley and the Tuolomne River Canyon pointed the way back up into the high mountains.

 Now we were flying over vast forests of pine, fir, and redwood on the Sierra’s more gentle western slopes. Large reservoirs—built to provide water for crop irrigation and recreational opportunities for water skiers and fishermen—lay strewn across the golden foothills like spilt green and silver paint.

 As we approached the towns of California’s Central Valley, I let the concerto’s third movement take over. It seemed more suited to an urban landscape. Soon the low coastal mountains were beneath us, and before long San Francisco Bay.

 It is now nearly a week later, and my mind is still aglow with the reflected light of D’Souza’s writing, Rachmaninoff’s music, and the High Sierras. God speaks in many ways—especially when we are attuned to unanticipated possibilities. I’m glad I looked up and decided to move to a window seat. I could easily have missed the whole thing.

 B.W.