Where do the interior visions of artists come from? What exactly guides the brush of an abstract painter?

John Chapman Lewis, a painter known to Washingtonians for years, opened his newspaper one day in 1980 to find a huge photo of the Mount St. Helens explosion. He gaped at it, couldn't understand why it looked so familiar. Then he remembered his own painting of an imagined lunar landscape. He brought it out.

They were the same thing. They were so similar it was spooky.

The painting was done in 1969.

Later he saw Ansel Adams' photo, "Frozen Lake and Cliffs," a stark picture of rocks and snow, and again it matched one of his paintings almost line for line, streak for streak, pattern for pattern.

"I train myself to remember what I see," said Lewis, who at 61 is artist-in-residence at Marymount College. "But I couldn't have seen those rocks. They're out in the Sierra Nevada, and I've never been west of New Orleans. I had never seen the Adams picture before, either."

One could say that any painter who works in muted colors and vaguely geometric shapes would be bound sooner or later to duplicate the shapes of nature. But in Lewis' case, it's the play of shadows, the patterns of light and dark, the very mood of the piece that repeats reality.

The recent rise of photo-realism is a somewhat different problem. Here, the borrowing is deliberate, and so exact that it raises the question of copyright, as in the case of Jack Goldstein's night view of the Kremlin under attack, taken literally from a Margaret Bourke-White photo, copyrighted by Life magazine.

But Lewis' pictures came from deep in his imagination, his lifetime memory bank of images synthesized from sources he could not possibly identify. Even the colors sometimes match, as in a moon painting he did in soft reds and pinks--hardly conventional moon colors--which hauntingly recalls a newspaper color photo of a moonscape taken a decade later.

What do we see, anyway? Isn't it true that most people of a given generation or century subconsciously agree to interpret what they see in the same way? And that it takes a great artist (some would say revolutionary) to make them see in a different way? Everyone thought factories were ugly until Charles Sheeler sang of their beauty. People thought mountains were just brown lumps until Ce'zanne lifted them up in airy majesty. Monet made us believe in blue haystacks.

These revelations are fascinating, but even more fascinating, perhaps, is the consensus that went before. Do John Lewis, Ansel Adams and the Associated Press photographer flying over Mount St. Helens all share the same instinct for what makes beauty? One thing is certain: The artist has to stay receptive, open to subliminal suggestion.

"When I was in kindergarten at the old Wilson Normal School at 11th and Harvard streets," Lewis said, "I had a speech defect, so I didn't speak. I withdrew a lot. I began drawing animals in the gravel with a stick. And then in grade school my drawings began to get attention."

He still has a drawing he did at 6. Later, after graduating from the Corcoran, he worked with aerial maps for the Army, before and during World War II. The mosaics of photogrammetry can be detected in his work to this day. At first, he worked from life, but recently he has been painting from sketches, his eye becoming more interior, imaginative. He is continually baffled by the sources of his inspiration.

"I was looking at my beagle Angie the other day," he said. "And there on her belly was this furry pattern. I couldn't think where I'd seen it before. Ah yes, that painting I did . . . "