A short excerpt from David Gerrold's 1973 The World of Star Trek:
The crew of the Enterprise is in no way meant to be representative of future humanity - not at all. They are representative of the American Sphere of Influence today. Their attitudes, their manner of speaking, their ways of reacting, even their ways of making love, are all contemporary.
We have met the Enterprise - and they are us. The crew of the Enterprise is twentieth century America in space.
And - although it takes a bit of justification - that's the way it has to be. Remember, this is drama we are talking about, as well as American television. It has to make money.
That means it has to have appeal and that its characters must be attractive and interesting - an audience has to be able to relate to them. Even if the show is alien to the audience's experience, the characters have to recognizable.
Neither Gunsmoke nor Bonanza are really about 1880. They are about 1972 men in an 1880 world. The Untouchables, when it was still on, was about 1966 men in a 1929 world. And Star Trek also is about 1966-69 men in a 2??? world.
This is the essential appeal of drama. As mentioned earlier, we watch a story because we are really testing ourselves. We are curious as to how we would react to an equivalent situation. In science fiction, we are also testing our culture. Thus, both the characters and the culture have to be recognizable parts of ourselves. They have to reflect contemporary values - not totally, but enough so that the viewer can follow.
Star Trek is not pure science fiction. It is not predictive science fiction, and it is not accurate science fiction. It was never meant to be.
Anyone who tries to shoehorn the series into that kind of arbitrary definition will be making the same mistake that every hardcore aficionado who grumbles in his beer about SF and the dramatic arts (grumble grumble) has been making since the very first episode of Star Trek began.
What Star Trek is, is a set of fables - morality plays, entertainments, and diversions about contemporary man, but set against a science fiction background. The background is subordinate to the fable.
I'm going to quote my earlier definition of SF: Science fiction is the contemporary fairy tale, it's the twentieth century morality play. At its worst, it's merely romantic escapism; but at its best, it is the postulation of an alternative reality with which to comment on this one.
That definition could almost be applied to Star Trek, but the difference between Star Trek and science fiction is that true science fiction requires that the background be logical, consistent, and the overall shaper of the story. The world in which the character moves determines the kind of actions he can make, and hence the plot of the tale. In true science fiction, the background is never subordinate to the plot.
As we have already seen, the Enterprise and her crew were able to function almost independent of their backgrounds. The only thing about them that remained consistent was their contemporary attitudes.
Star Trek's backgrounds were always subordinate to the story - and because of that, it never quite achieved the convincing reality of true science fiction. Its use of a science fiction background gave it the appearance of science fiction; but in reality, Star Trek was a science fiction-based format for the telling of entertainments for and about the attitudes of contemporaray America. And that's called science fantasy...
The reflection of American man - no, make that just Man - freed from the context of the American culture (or any specific culture) and placed in a series of alternate realities, would be a powerful dramatic vehicle for educating, enlightening - and especially for entertaining the American public. If the dramatists scripting the series were allowed to do so with no holds barred.
Just as Archie Bunker is forced to confront his own attitudes week after week, so would such a Star Trek allow its heroes to examine their attitudes in a multitude of situations - and the viewer with them. Captain Kirk would become a symbol not for American ingenuity - but more important, for the American dilemma: how best can we use our strength? Each week, he would be making crucial decisions about problems that we would see relating to our own lives and environments.
This writer submits that Star Trek was, and still is, the finest format ever designed for American series television. There are few shows that can match it for potential. But, potential must be realized. An unfulfilled potential is a very special kind of failure.
- David Gerrold, The World of Star Trek (1973), 47-50.