Once upon a time, a mysterious extraterrestrial creature descended to the earth. He was innocent, wise and altogether gentle, but just about everyone who knew he had landed misunderstood him and conspired to get rid of him. Only a few young people saw his true benevolence, and they and the creature became inseparable. In return for their faith, the alien established a strange and powerful bond with his earthling disciples: they suffered together--even when they were miles apart--and he healed their wounds with a touch of his other-worldly finger.

But before long, the creature's life-blood began to ebb, and after a struggle he collapsed and was taken for dead. And then just after he was carted away, he was dramatically resurrected, and after uttering a few words of inspiration, he returned to the great celestial beyond.

YOU DON'T HAVE TO SCRATCH very hard at the wrinkled brown skin of the summer's most adored cultural hero to find the skeleton of an old superstar. Even the advertising campaign for "E. T." hints coyly at a Significant Parallel for sharp-eyed moviegoers to discern: that now-famous elongated finger stretching down from the heavens to point at a human finger reaching up from the earth. Remind you of any famous creation scenes on chapel ceilings? One wonders: since E. T. 's last-minute Easter-like recovery conveniently leaves the door open for a sequel, can we expect to see the little alien in his next adventure merrily waddling along the surface of some suburban swimming pool, or turning Elliot's bedtime glass of water into something with a little more punch to it?

One viewer of "E. T." wrote this summer, in a letter to The New York Times, that the success of a movie with persistent associations to the life of Jesus Christ just goes to show that even in this high-powered age, the greatest story ever told still commands enormous audience appeal. That's undoubtedly true, but the phenomenal success of "E. T." has a broader significance as well: it marks the culmination of two filmmakers' long effort to glorify the mystical at the rude expense of the rational.

The efforts of this pair are not slipping by unnoticed, either, for they are unquestionably the two most successful directors in Hollywood: George Lucas, the creator of "Star Wars," and Steven Spielberg, whose most recent offering is "E. T." Consider the way these two have filled their last few movies with elements of religious mysticism:

* A galaxy of characters--in two movies, with a third on its way--who are all guided--or defeated--by an ethereal "force;"

* Another nebulous power--this one inexplicably takes hold of a few dozen common folk and draws them to a spaceship's landing site;

* An ancient ark, which, when tinkered with, empties out a cloud-burst of evil spirits with the power to incinerate anyone in their path;

* A houseful of poltergeists that zip out of a television set and swallow up a four-year-old girl. The only person who can call her back is her mother, by thinking hard about how much she loves her daughter;

* And now, as we all know, that leathery little messiah.

THESE RELIGIOUS OVERTONES represent a new twist to the familiar pattern of Hollywood occult and science-fiction. Their space heroes don't win their battles with zap-guns alone; they've got to have the force. Magic spells cannot kill their monsters--the mother has to conquer them with the strength of her faith and love of family. As for their creatures from outer space, they cannot drop dead without being swiftly resurrected.

Of course there is nothing wrong with making movies--or books or paintings, for that matter--that depend on the irrational rather than the rational; to disparage that would be to blunder into an ageless debate over the merits of faith versus reason--a debate that shows no signs of resolving itself. But there is something unsettling about the way Spielberg and Lucas, in their passion for faith, take pot-shots at reason.

Think about the role scientists play in these movies. In "Close Encounters of the Third-Kind," they are a sinister pack of bureaucrats who stifle the simple, pure-hearted spirits of the U. F. O. witnessers. Indiana Jones, the anthropologist hero of "Raiders of the Lost Ark," is spared the ark's deadly wrath only because he refuses to look at it, hardly the most scientifically curious of approaches. The various technicians who tromp through the haunted house in "Poltergiest" are useless, for all their sophisticated machinery, in the face of the specters who have set up shop there.

But the scientists in "E. T." are cast in the most insidious roles of all. For most of the movie, they are shown only as disembodied legs, striding conspiratorially about as they seek out the little alien. When they arrive at Elliot's house, marching en masse in their spacesuits, it is nothing less than an enemy invasion. And it is in their custody that E. T. suffers his near-fatal relapse--they do not realize, as the movie's three children do, that what ails the creature is a deep-felt need to communicate with his home-star.

The only sympathetic exception among the doctors, who lets Elliot share a last moment with E. T. after the lab-technicians have zipped up his body bag, is a singularly flaky character, who confesses his abiding wish to look up into the sky and see spaceships. (Imagine how hard even the most generous-spirited of us would laugh if a Harvard scientist tried a line like that.)

This sort of space-cadet's anti-intellectualism is especially troubling at a time when real-life intellectuals are suddenly finding themselves threatened by rigid fundamentalists. Proponents of the bankrupt theory of creationism have launched a surprisingly successful crusade against teachers of evolution. Stern schoolboards have revived the archaic practice of book-banning; their hysterical search for evil influence in the most innocent quarters calls to mind nothing so much as a swinging single's fear of herpes.

With forces like these at work, the best message for Hollywood's opinion-shapers to send out would be a decidedly terrestrial one.