Colin McCahon has written that his first artistic experience was watching a sign-painter writing “Hairdresser and Tobacconist” on a shop front. “The grace of the lettering as it arched across the window in gleaming gold, suspended on its dull red field but leaping free from its own black shadow, pointed to a new and magnificent world of painting. I watched from outside as the artist working inside slowly separated himself from me (and light from dark) to make his new creation.” Later, when McCahon himself became an artist, he too used other people’s messages, copying passages from the Bible and elsewhere. His feeling of a splendor in everyday events led him to look at cricket scoreboards, handwritten signs in fruit and vegetable markets, and sometimes more sophisticated advertisements. (Questioned about a text included in a painting of 1947 he replied that he took the yellow from Byzantium and the lettering from a packet of Rinso detergent.) And he still believed that the artist separated light from darkness: “painting is contrast,” he would tell students. If that is true of painting, it may be equally true of morality.

Though McCahon is 65, his work is little known outside his native New Zealand. Focusing only on paintings that employ words and numbers, the selection here (a show which began at the Sydney Biennale) offered a glimpse of an achievement as hard to categorize as it is to interpret. From 1947, when he was painting crucifixions set in his native town and featuring people he knew, come scrolls and cartoon speech bubbles. Later pieces show words inscribed in white on black, sometimes with landscape references below, arranged like concrete poetry; the calligraphy and arrangement of the words modify, dramatize, even reverse the meanings of the given texts. Lastly come numbers, arranged separately or in series. McCahon’s lettering can be fluent or clotted. It shifts at will from Roman to Arabic numerals, from capitals to handwriting. A register of seismographic sensitivity, it invests the text with reactions so personal that they float free, ratifying the borrowed text as a form of ancient wisdom. Movement from word to word, letter to letter, lends the text duration, interpretation, rendering it as a conductor renders a score.

“Are there not twelve hours of daylight,” reads the text of an untitled work from 1970, the first words boldly stated, confidently printed at the top of the canvas against what would be the sky in a landscape, “daylight” capitalized above a sliver of white light appearing or disappearing on the horizon. “Anyone can walk in daytime without stumbling because he sees the Light of this World”— and “this” is accentuated, as well as the “Wo” of “World,” though the words are becoming fainter and harder to read, their transcription becoming regular, more of a chore that there is little certainty of carrying out; the dependence on this world may be a cause of collapse rather than of certainty. “But if he walks after nightfall he stumbles, because the Light fails him.” The text itself stumbles into darkness now, after a heroic effort of will over the “L” of “Light,” a solidly attested right angle, an axis built rather than inscribed. Time and again it seems that the words are slipping away into invisibility. Finally the achievement of solid whiteness comes to seem born of necessary human weakness, a frail attempt to believe in a God of certainties we are too slight to comprehend.

McCahon is preoccupied with doubt. Among the Bible texts he chooses are the moment when the crowd witnessing the Crucifixion expects a higher power to intervene; Moses asking God His name; and the miracle of Lazarus, narrated in part and in entirety, containing Christ’s apparent indifference to the dying. For McCahon, naming, the showing forth of the spirit in tangible terms (the miracle), the “I-thou” separation, and the need to perpetuate necessary divisions are subtly connected. If the signs he uses are allowed to be themselves—deceptive, quicksilver, residents of more than one domain-that acceptance of mutability, a kind of constant play, is also linked. McCahon seems to believe that neither revelation nor reason can be relied on as a way to faith. In this he may resemble the preacher in Ecclesiastes, part of which he rewrites in a stunning recent work. Yet the bleak tone of voice struck here is not to be the one for which McCahon will be remembered. Another tone cannot be invoked, but occurs of its own volition; without the pessimism, perhaps, it could not exist. Consider some of the “Blinds” paintings from 1974, wordless and numberless, McCahon at his most cracker-barrel and literal minded. Compare them with the whiteness of the sky on the right-hand side of a vast painting, Practical Religion: The Resurrection of Lazarus Showing Mount Martha, 1969–70. Then remember the artist’s childhood memory of a man painting himself out of vision as he makes his work of art. Seeing nothing, a drawn blind, and experiencing a revelation are oddly similar in their constitution, because both may be beyond any chosen language. McCahon presents the first as leaving well alone, the second as a wiping out of the kind that takes place on shop windows when decorators are at work inside. They exist as parodies of each other. To us, that is. Not to McCahon, for whom the mundane and the spiritual are not irreconcilable.

—Stuart Morgan