When it comes to fantasy and science fiction, Hollywood has a split personality these days.
On one hand, there's the sweetness and light of ''E.T. The Extra-Terrestrial.'' On the other, there's the grim savagery of ''The Thing.''
And in the middle, there's ''Star Trek: The Wrath of Khan,'' with characters torn between saving the universe and solving their own midlife crises. Not to mention ''Poltergeist,'' pitting good against evil in a cozy suburban setting.
Put them all together and you have very mixed signals coming from the cinematic dream factory. This makes for unpredictable moviegoing, which is all to the good. But it also reflects a real confusion in current attitudes toward science and technology and a deep ambivalence about humanity's place in the cosmos.
There is little question that science fiction mirrors the fears and aspirations of its period. For example, remember the sci-fi films of the 1950s, in the early days of the nuclear age? The two big themes were atomic energy and space travel, and neither boded any good. Scientists who tinkered with nuclear power ended up with giant ants (''Them'') or giant spiders (''Tarantula'') who killed everyone in sight. ''The Incredible Shrinking Man'' got that way from a cloud of radioactive dust, while the Japanese monster ''Godzilla'' was roused from a million-year hibernation by the Bikini hydrogen-bomb tests.
With rare exceptions - such as ''It Came From Outer Space'' - outer space was viewed with similar suspicion, in films from ''The Blob'' to ''Night of the Blood Beast.'' Titles like ''War of the Worlds'' and ''When Worlds Collide'' speak for themselves, and when the visitors land in a movie like ''Earth vs. the Flying Saucers,'' the first response is to call the Army and start shooting at them. Moviegoers of the '50s looked to the stars, speculated that there might be something out there, and promptly decided to be afraid of it.
It doesn't take much deep analysis to connect this kind of moviemaking with the cold war atmosphere of the time. Memories of World War II and Hiroshima were still fresh - it's no accident that Godzilla and his progeny hailed from Japan - and many people associated nuclear energy more with death and destruction then with power plants and ''atoms for peace.'' Movies about outer-space monsters seemed to fit the distrustful mood of a country preoccupied with McCarthyism and East-West hostility.
Such attitudes dominated Hollywood sci-fi for years. The big exception was '' 2001: A Space Odyssey,'' which suggested in 1967 that beings from outer space could be benign and even paternal. But it was a long time before Hollywood followed up on that idea. The paranoid view reigned until ''Star Wars,'' which sprinked the universe with friendly and even lovable creatures eager to join the earthlings against the evil Empire. The cosmology was still geocentric, and the moral issues were simplistic. Yet outer space was seen as a source of help as well as hostility.
And then Steven Spielberg changed the course of science fiction with ''Close Encounters of the Third Kind,'' a glowing vision of intergalactic optimism. Here was a movie suggesting that spacemen could land right in our own backyards, just when we least expect it, and it would be the best thing that ever happened to our battered old planet. Spielberg didn't just hint this, or keep it in the background. ''Close Encounters'' was a proud hymn to outer space and the most magnificent possibilities of the future. And audiences gobbled it up. Hope and good cheer were in style at last.
It's no secret that Spielberg's new ''E.T.'' is a continuation of that exhilirating trend. This time we get to know the alien well, and not only is he friendly, but his best friend and natural ally is a little boy. In an echo of ' 50s paranoia, a gang of menacing grownups is seen from time to time, hunting the spaceman and his pal Elliott - just like the government lackeys who almost gum up the climactic meeting in ''Close Encounters.'' Yet even they turn out to be good guys who want to help, even if they don't know how. The end is a triumphant victory of trust over suspicion, magic over technology, and young Elliott over the adults who don't really understand. It's a sentimental celebration of sci-fi , fantasy, and pure fun.
And that would be the happy ending of our story if ''E.T.'' were the only major science-fiction release of the season. But there are others to contend with, and some deliver a drastically different message.
Most striking of the lot is The Thing. Directed by shock specialist John Carpenter, it's a slick thriller with expertly handled monster scenes that are as scary as they are sickening. It's also a complete throwback to the most paranoid attitudes of the past, as if the popularity and influence of ''Close Encounters'' had never existed.
In a way, this isn't surprising. After all, ''The Thing'' is a remake of a ' 50s classic, ''The Thing From Another World'' by Hollywood master Howard Hawks. And the plot originally came from a 1938 story by John W. Campbell Jr. called ''Who Goes There?''
Like many seminal sci-fi tales, it's poorly written and oddly structured. But it reflects a late-'30s sensibility that shows up in other works of the period: an admiration for science combined with an uneasy anticipation of other ''life forms'' lurking around the corner. (See ''The Time Machine'' by H. G. Wells, with its spooky Morlocks, or ''A Martian Odyssey'' by Stanley G. Weinbaum, with its ''silicon life.'') The story paved the way for dark musings about dehumanization that would soon fascinate Hollywood in movies ranging from the ' 50s ''Invasion of the Body Snatchers'' to the '80s ''Alien.''
Then too, filmmaker Carpenter has never been known for gentleness. After an attractively lighthearted start in ''Dark Star,'' his work has thrived on fear and loathing from ''Halloween'' to ''Escape From New York.'' Nor does he favor clear-cut confrontations between good guys and bad ones. Especially in his most recent pictures, the heroes are as shadowy as the villains, and the environment is so adverse it hardly matters whose side you're on.
All this comes together in ''The Thing,'' the antithesis of Spielberg's friendly vision. The visitor from space is evil, insidious, polymorphous, and almost unstoppable - needing just 27,000 hours, we are told, to take over the world. On top of that, the battleground between it and us happens to be the frozen Antarctic, where normal life is no bed of roses. It's the bleakest vision of the year, and to add to the distress, Carpenter inserts gore with distressing zeal.
It's not only a far cry from ''E.T.'' It also misses many positive qualities of the 1951 version, which concentrated (in typical Hawks fashion) on the comradely courage and proud professionalism of the heroes. Carpenter reveres Hawks, but he has lost sight of the taste and tact that made Hawks's adventures memorable. Notwithstanding its own virtues - suspense, dazzling photography, and good supporting performances - the new ''Thing'' is suspiciously eager to revive the least attractive attitudes of bygone film fantasy. Like the season's other fantasy remake, Paul Schrader's ''Cat People,'' it sets out to update a classic by adding the facile sensationalism of the '80s and ends up diluting the modest virtues of its source.
Still, it must be noted that the last major movie of this violent ilk - ''Alien'' - was a big hit, and ''The Thing'' probably will be, too. Yes, the Spielberg optimism has struck a hugely popular chord in ''Close Encounters'' and ''E.T.'' But today's audiences also respond to a far more horrific view of the universe and its possible inhabitants.
And that's the nub. Science fiction must inevitably be split in radically different pieces at a time when people thrill to the potential of the computer age, filling their homes with calculators and video games, then take to the streets and demonstrate their dread of nuclear weaponry and atomic power plants. In an age when science is seen as both a blessing and a curse, it's logical that science fiction should reflect the uncertainty.
Maybe that's why Star Trek: The Wrath of Khan has drawn such crowds, even though it's talky and sometimes tedious. Admiral Kirk, formerly Captain Kirk and again commanding the Starship Enterprise, spends more time mooning about personal problems than vanquishing the villain; when the plot isn't busy with mumbo-jumbo about a new ''life force,'' with a couple of rather slimy shock effects, it crawls through long scenes about fractured family relations and growing old.
For a major sci-fi release in the ''Star Wars'' era, it's surprisingly slow and even maudlin. But there's a human quality to it - boredom and all - that audiences sympathize with, just as they relish the ghostly action of ''Poltergeist'' in its dull-as-dishwater suburban setting.
So if you're looking for the next big trend in science fantasy, maybe this is it: humanized heroics. As a pair, ''E.T.'' and ''The Thing'' make a tantalizing dialectic. But maybe real people are still the bottom line of Hollywood's most enduring art. And maybe the biggest future hit won't be ''E.T. Returns,'' but rather - starring the spaceman's earthbound friend - ''Elliott Never Left.''