THERE has always been a didactic seriousness about "Star Trek," and it has a vigorous presence in "Star Trek: Nemesis," the latest movie in the series.

That the filmmakers would even use a term like "nemesis" also says something about Trekkie fans: They are apparently expected to be literate as well as able to endure long stretches of meaningless technobabble between battles and cheesy jokes.

In Greek mythology, Nemesis was the goddess of retribution, but the term has been used to mean both the reward for arrogance, and an opponent that can't be overcome.

It would be giving away too much of the plot to reveal whose arrogance is rewarded or who encounters an unbeatable enemy in this adventure featuring the cast of television's "Star Trek: The Next Generation."

In any case, one of the clever, interesting things about this film is the geometric way screenwriter John Logan ("Gladiator") has plotted it so that it is filled with parallels: Both Captain Picard (Patrick Stewart) and his relentlessly curious android Lt. Commander Data (Brent Spiner) encounter their doubles and perhaps their matches in outer space.

In the original series, creator Gene Roddenberry used plots involving doubles to make philosophical points.

One episode involved Kirk's splitting into two problematic men - a wholly evil Kirk without a conscience and a wholly good Kirk with insufficient aggressiveness to lead.

In "Star Trek: Nemesis," the filmmakers use cloning and robotics to explore questions of "nature vs. nurture" and free will.

The film's point is admirable - that the essence of being human is being able to transcend both the biologically and socially given.

In other words, we can escape paths that seem determined by our pasts or our DNA.

The movie gets there by means of a plot that sends the USS Enterprise on a diplomatic mission to the home world of the hostile Romulan empire, where a sinister new leader, Shinzon (the excellent Tom Hardy) has taken power and claims to want peace with the Federation.

It soon becomes clear that Shinzon, a native of Romulus' lightless sister planet Remus, has a very personal interest in Picard.

As always, the Earthbound sequences are cheesy, the attempts at comic relief are hokey and the technojargon is exhausting. And there are some unintentionally funny scenes featuring Jonathan Frakes' 1st Officer Will Riker.

But while "Star Trek: Nemesis" isn't nearly as good as the best Nicholas Meyer-written movies like "The Undiscovered Country," it is far from the worst, thanks to the topical issues it raises, the performances of Stewart and Hardy, and that essential feature - a decent full-on space battle.