Playful Intersections of Art and Life : THE LYRE OF ORPHEUS : <i> Robertson Davies (Viking: $19.95; 472 pp.; 0-670-82416-X) </i>

Robertson Davies loves to mock the complacency of his native Canada--”the home of Modified Rapture,” he calls it. All his work uses satire to encourage sentiment, challenge what passes for decency with the immodesties of passion. He writes with a wit inherited from the formalities of the English novel tradition, but his heroes are Jung, Rabelais, and the cultural desperadoes who would defy civilization to inject it with life.

The lyre of Orpheus of Davies’ title is supposed to permit entrance to the underworld, and that’s where Davies wants to guide us in this third and concluding volume of his most recent trilogy. Characters and incidents from “The Rebel Angels” and “What’s Bred in the Bone” (the two previous volumes on the Cornish family and their friends around and about Ploughwright College) return in “The Lyre of Orpheus,” but brief summaries provide enough background to let the action stand on its own.

“The Lyre of Orpheus” is a talky book--a playful series of conversations and arguments about the intersections and contradictions of life and art. Arthur Cornish’s Foundation, established with his deceased uncle Francis’ money, proposes to support a disheveled, if talented, graduate student, Hulda Schnackenburg, as she attempts to complete the score for, and mount a production of, an opera based on the Arthurian legend of the Round Table, “Arthur of Britain, or, The Magnificent Cuckold,” left unfinished in the 19th Century by E. T. A. Hoffman.

The effort enlists the talents of cleric and teacher Simon Darcourt as librettist, of young Geraint Powell as director, of composer Dr. Gunilla Dahl-Soot as Schnackenburg’s mentor, and of Arthur Cornish, his wife Maria, her fortuneteller mother, and other assorted deans, professors, musicologists, and lovers and critics of the arts.

Meantime, Darcourt’s work as the biographer of uncle Francis Cornish has led to a startling discovery about a famous triptych, “The Marriage of Cana,” attributed to the so-called “Alchemical Master” and supposedly painted in the 16th Century. The painting proves to be the work of Cornish himself, with significant people from his life providing models for the various figures. Patron of the arts Francis, then, turns out to be artist Francis, creator of a triptych in a traditional style that mirrors, and masks, his own life and times.

And this is also what Davies is doing with his “Cana” and his opera on Arthur in this, the third panel of his third trilogy of novels. Near the end of the book, Darcourt quotes Keats that “A Man’s life of any worth is a continual allegory,” explaining that each life has “a buried myth” that takes “figurative” shapes “few eyes can see.” Davies reveals something of his past and his years as a teacher and dramatist and fiction writer in this story of how art--painting, poetry, opera, and the stylish life--bares the face of the present in the form of the past.

He throws in literary and cultural asides to everything from Germanic versus Latinate roots of words to the Tarot and Lewis Carroll’s mock-epic, “The Hunting of the Snark,” to insist on the parallel paths of culture and life. (He even has Hoffman’s disembodied ghost, cast off in a limbo reserved for artists who leave their work unfinished, comment at the end of each section of the novel on events, interpretations, and the similarities and differences between then and now.)

What matters about all this arty stuff is the way that seemingly unalterable remnants of other times take the shape of, as well as predicting the destinies and meaning of, the present. The old tales cross over into modern life, their original forms literally and figuratively fleshed out in contemporary ethics. As the characters work to aid or discourage the opera production, each comes to imitate a figure of Arthur’s court. So when Gunilla hits it off with Hulda in the bath, Simon discovers himself as both Merlin and the Fool in the Tarot, Maria and Geraint get it on like Guinevere and Lancelot, and the kindly and lordly Arthur suffers through the mumps and cuckoldry to find himself a father, their fates seem both altered by and patterned after the art they adore.

The key to Davies’ ambitions is the ideal of alchemy: the transformation of dross to gold, of the discarded past to resplendent present, through the secret spells of the Gypsies, artists, and others who can realize the magic in the seemingly mundane (like the Alchemical Master painter, however disguised his identity and intentions).

Such material conversion, however, is just what fails to occur in “The Lyre of Orpheus.” Davies’ comedy--what he calls (referring to Rabelais) a “cleansing humor”--is engaging, and successful in deriding the myopias of middle-class satisfaction. Davies maneuvers his plot with great skill, toys engagingly with ideas. But the novel doesn’t so much make the surface over as make it charming. The book is undermined by the contradictions apparent in Davies’ strategies: He writes about feeling, but not very feelingly; he honors the truths of the heart in the bemused voice of the mind. The wild carnival of life--the sexuality that produces a child, the revelations in great poetry and music, the visionary possibilities of the Tarot--is more alluded to than represented, a matter too much of hearsay and not enough of sensations of the world’s base and venial fumblings.

Unlike his earlier “Fifth Business,” where soul and idea merged so successfully, Davies has not been able to liberate his prose here, and invest his story with the wisdoms of the body, the anarchic willfulness of the spirit, and the magnanimity of love that he celebrates.