Star Trek writers (most recently Ron Moore) have occasionally complained about the restraints that the vast body of canon placed on their inventiveness, particularly after hundreds of stories had been told. But the other side of canon is that writers largely invented it, by using what had been established or suggested in earlier Star Trek stories as a springboard to create new stories.

Spock was established as half-human and half-alien, raised on the planet Vulcan. Theodore Sturgeon used that bit of canon to explore Vulcan culture and an aspect of Spock’s inner conflict in the classic episode, “Amok Time.” Other writers used Sturgeon’s inventions and those of other writers—as well as those of Leonard Nimoy and other actors—as starting points or important features of their new stories.

That’s a simple example. But here’s another that may be more of an issue: a first season episode, “Balance of Terror,” showed the Enterprise getting the first glimpse of an old enemy, the Romulans, and they look a lot like Vulcans. This added a subplot about race prejudice to what was basically a story about tactics of warfare (similar to the 1958 film The Enemy Below, about a U.S. destroyer and a German U-boat.)

But it also inspired a thread that ran through the rest of Star Trek about the relationship of the Vulcans and Romulans, eventually involving Spock going underground on Romulus to facilitate re-unification in two episodes of TNG. But today, there is uncertainty whether the new movie will honor this bit of canon, or for that matter, the part that says the Federation hadn’t actually seen a Romulan before the time covered in that episode.

Yet the function of that first season subplot was to generate more stories. Canon became a starting point also for those who created non-canon stories, in novels and short stories, fan fictions and independent films, comics, games and so on. It’s true that canon limited what writers could create for Star Trek. But as Star Trek director and writer Nick Meyer has said, limitations can be a spur to creativity. It may seem paradoxical but the limitations of canon had a creative role in expanding the Star Trek universe. By building new stories on prior ones, Star Trek created not only a self-consistent and believable universe, but a rich and complex alternate reality, as big as a future.

Keeping track of canon and continuity was undoubtedly a pain for writers and producers by the time of “Deep Space Nine” and “Voyager.” But it became a particular cause of apprehension among fans when Star Trek stories started going backwards with “Enterprise.” If new stories about the Star Trek past clashed with what had been established about the Star Trek future, the credibility of both sets of stories could be damaged. Causality and time line weren’t all that was called into question. The sanctity and therefore the meaning of canon was threatened.

That nervousness and even suspicion has appeared again because the new Star Trek movie is also set in a time before the original series began, but even more dangerously, features many of the same characters. A lot is at stake—maybe including everything that follows in the Star Trek saga.