The Irish novelist James Joyce called them "epiphanies" — moments in life when something previously hidden becomes visible, or when we see it in a new, revelatory way.

These Joycean moments were examined Thursday evening in "Discovery of Sight," the opening concert of Twin Cities vocal ensemble Cantus' 2017-18 schedule.

Cantus recently returned from a recital tour of China, Taiwan and South Korea. It clearly left the group in prime technical condition. Hugo Alfvén's "Aftonen" ("Evening"), was hummed with smoothly blended harmonies, distilling a placid, consoling sense of twilight in the composer's native Sweden. And fireflies in the Japanese night, "their rear ends sparkling in the dark," inhabited the flickering shadows of "Hotaru Koi," a Japanese children's song. The gentle pulse of nocturnal things was evocatively summoned by Cantus' thrumming performance.

Monotony was an occasional danger in the program's first nine pieces, most of which proceeded at a moderate, dreamy tempo.

Kenneth Jennings' "Do Not Go Gentle Into That Good Night" was a partial exception. Here, the crushed harmonies and sudden roiling crescendos in Jennings' setting of Dylan Thomas' famous poem elicited a sense of drama generally missing in the recital's first half.

Part two had more variety of mood and inflection. Brightly optimistic arrangements of "Simple Gifts" and "Morning Has Broken" showcased the group's knack for making hackneyed tunes sound new — and potentially hokey sentiments seem genuine.

A certain quirkiness characterized Gabriel Kahane's "Coffee With Borges," a brand-new work composed especially for Cantus. Whooping glissandos caricaturing the "blah, blah, blah" of Shakespearean rhetoric were executed with relish by the eight singers.

Overall, Kahane's piece meandered a little structurally, not quite clinching its central proposition that there are ways of seeing and experiencing the world when eyesight is absent.

The truest moments of Joycean epiphany came late in the recital, in bubbling gospel arrangements by Cantus alumnus Paul John Rudoi and 20th-century composer Jester Hairston.

Rudoi's take on "Yonder Come Day" fastened on the piece's infectiously vibrant rhythms, underpinned by baritone Matthew Goinz's percussion shaker and a clap-along contribution by singers and audience. Hairston's "In That Great Gettin' Up Mornin' " had a similarly tingling effect. Where some of the program's earlier music set poetry that seemed abstruse and wishy-washy, a sense of fresh, urgent revelation gleamed with startling clarity in these two spirituals.

In Cantus' joyful, unpretentious performances, they cut directly to the quick of the evening's message — that even in a world we habitually view through dark lenses, moments of brilliant illumination are possible, some of them mediated by music.

Terry Blain is a freelance classical music critic for the Star Tribune. He can be reached at artsblain@gmail.com.