What we've got here, public TV fans, is the germ of a terrific series for PBS, along the lines of "Cosmos," or "The Shock of the New," or "Civilization."

The subject is "Joseph Campbell: Myths to Live By" and the show is "Bill Moyers' Journal," tonight and next Friday at 9 on Channel 26.

"A myth is a private dream and a dream is a private myth," says Campbell, who, at 77, is the grand old man of mythology. This is not mythology done up Edith Hamilton style, retelling the Greek myths, but myths a la C. G. Jung, which is to say mythology seen as the collective unconscious, the same images reappearing over and over, around the world: gardens from which we're exiled, heavens to which we ascend, heroes from Lancelot to Krishna to Daniel Boone, virgin births, vision quests. "It will be one constant story that we find," says Campbell.

It's about time somebody got him on the tube. He's been a bit a cult figure since the 1960s, when the counterculture (remember the counterculture?) got interested in ethnic religious practices and Jungian psychology. The "Whole Earth Catalogs" list his books, which include "The Masks of God" in four volumes, "The Hero With a Thousand Faces" and "Myths to Live By."

He'd been known for years in academic circles from anthropology to theology. After his education at Columbia, where he was also a world-class half-miler, he taught at Sarah Lawrence College for 30 years. But he hasn't been terribly fashionable. Mthology isn't quite art, where all sorts of mystical ruminations are permitted by critics, and it isn't quite science, with lots of statistics and quantitative analysis.

"Myth is the secret opening through which the inexhaustible energies of the cosmos pour," he says, during two hours in which he explains events as disparate as the funeral of John Kennedy, Neanderthal rituals, the ascendance of Japan, Stanley Kubrick's "2001," King Arthur's knights and the Holy Grail, the enlightenment of the Buddha, men landing on the moon, the heroism of John Lennon, the gray tyranny of economics and Buffalo Bill.

Everything, in other words. Myths explain everything, which is the best and worst you can say about them. Modern education trains us to beware of universals of this order. It's a kind of prudery that is accompanied by a growing craving for them as seen in phenomena from cults to sword-and-sorcery movies.

In any case, Moyers found the right guy to talk about mythology, and the visuals should have been great. But whether it was a low budget or lack of imagination, Moyers blew the chance to turn two hours of lecture into two hours of real television. He wouldn't have had to fly Campbell around the world like J. Bronowski in "The Ascent of Man." All he needed was more slides, more stock film footage like the views we get of men on the moon.

Words alone, let's not forget, can suffice very nicely. But next time out somebody out there in pub-vid-land should give somebody a pile of money to do this subject as it deserves to be done.