Who says the future can't wait?

With Labor Day a week away, we've long since reached the season of the summer's-almost-over-people. They're the folks you remember from your childhood who remarked, any time after August 1st, ''Well, it won't be long now.''

Only a very innocent or a very backward child would ask, ''Not long till what?'' - allowing the tormentor to pounce with the answer: ''Till school starts again.''

There's a little something to be said for living in the future, and from time to time philosophers have said it, arguing that the capacity to frame a future (and a past) is what distinguishes human beings from animals. But a well-developed sense of time can be a terrible nuisance to its possessor, and the people who have to live with the possessor.

The ''Well-it-won't-be-long-now'' adult will still be there ten years later to tell you (as if you didn't know), ''Well, it won't be long before you're through school. What are you going to do then?''

We once lived with an otherwise model adult who had clocks ticking within his clocks. His apprehension that his friends and loved ones were falling behind some schedule of life - perceived only by him - drove him into a frenzy of mixed metaphors.

''You're going to miss the boat,'' he would cry when his timetable told him somebody should have decided upon a career or gotten married. ''The party's started, and you're not there.''

A couple of years later the refrain would escalate - with many a headshake - to read: ''If you haven't done it by now, you never will.''

All this can be enough to turn the harangued victim into a late bloomer - though late blooming is another story.

Everybody, to some degree, is a futurist. What distinguishes a normal forward-looking person from an obsessed specialist? We suggest the ice cream cone test.

If you are a normal forward-looking person, as you take the first lick, you will anticipate the first crunch of the sugar cone below. Don't worry about that.

If you are a futurist, that first lick will drive you well past the first crunch - and even beyond the first day of back-to-school. You will find yourself skipping to the year 2000 - fantasizing yourself ordering a vanilla ice cream cone with jimmies, and being handed a white cube with black specks on it.

If you are a true futurist, you will think this is a good idea.

It is, in fact, the mark of a true futurist that he or she waxes enthusiastic about just those future-whiz marvels that leave the rest of us pining for the 18 th century: synthetic food, disposable clothing, domed cities.

If you are this kind of futurist, you have our permission to worry.

It is time that futurists be put in their place, which is not, as they tend to assume, on the hard leading edge of history. The soft misty boundaries of science fiction are more like it.

We condescend to those who, as we say, ''dwell on the past.'' We call them nostalgic weaklings, escapists from the present. But aren't most futurists doing the same thing, in the opposite direction? Rather than qualifying as the practical folk, the planners - if only they would! - they are more likely to be scenario-spinners, Star-Trekkies: future-escapists nostalgic for what has not yet been.

These galaxy trudgers live in the Now no more than the refugees strolling down Memory Lane.

Herman Kahn, writing of ''The Coming Boom,'' and Lawrence Welk, playing yesterday's polkas, may be closer than they think.

Whether you keep time-past by a grandfather's clock or time-future by a digital watch, you are appointing time as your tyrant.

So we want no more talk about summer's-almost-over for at least a week. On the other hand, when March comes, we'd be glad to hear the look-ahead people say , ''Well, winter's almost over.'' But the funny thing is, they never do.