I can remember when people actually talked about reducing the debt. There were two things wrong with that concept: It was too easy to understand and we couldn't do it.

So we began to talk about reducing the deficit. Reducing, that is, the annual amount by which the debt increases.This gave us some breathing room - as did the Reagan administration's courageous adherence to the principle that it is evil for the government (as against Republican candidates or individual members of the Department of Housing and Urban Development) to take money. As a result we voters have enjoyed the freedom to elect congressmen for spending more on us and presidents for cutting our taxes.

Now we can't reduce the deficit either.

So we need to come up with something new and more sophisticated to talk about reducing. The deficit as a percentage of the gross national product (or is it the gross national product as a percentage of the deficit?) may seem a handy fallback, but the d. as a p. of the GNP (or vice-versa) won't fit into a headline, and anyway I believe we have already stopped reducing that too.

Here's a thought: the debt/date ratio. The debt/date ratio would be derived by dividing the debt by the date.

For example, say the federal debt is $2.8 trillion on Jan. 1, 1991. The debt/date ratio would be $2.8 trillion divided by 111,991. Since the date always increases - not only annually, but daily - we would have a sporting chance of reducing the debt/date ratio without recessionary tax increases or painful cuts in spending.

Indeed, the only time the debt/date ratio would be bound to go up would be at midnight on New Year's Eve, and who cares then? The debt ratio would of necessity be higher in January than in December, but the administration might well be able to claim at any given juncture that the debt/

date ratio was pretty good for this time of year.

The nation's indebtedness would become more like the weather.

Then again, the weather is something we seem to have been doing the wrong thing about or to. We're told 1990 was the warmest year since man has been keeping rec-ords. It is possible that the debt/date ratio would be so warming as to produce what might be called a Greensfee Effect: if too many days of the year seemed like good days to knock off and play golf.

On the other hand the debt/date ratio will have a chilling effect if the debt increases faster than the date. And it undoubtedly will.

Abstruse formulas are good for shifting the burden of worrying about the economy from the taxpayer to tax-exempt think-tanks, where it belongs.

Economists could speak of Total Money, a figure that would surely not be reducible (thanks in no small part to baseball salaries), but here's the beauty of it: Total Money doesn't sound like anything we would want to reduce.

Just thinking out loud here. But maybe I have got to the heart of the problem. Maybe instead of trying to come up with something we can realistically reduce we should stop thinking reductively. When we think national indebtedness, perhaps we should think growth. What other country in the history of the world has been able to run such a munificent tab?

Back when we were trying to figure out how to end the Vietnam War, Sen. George Aiken of Vermont suggested we declare victory and then get out. Perhaps it is time now to declare solvency: Our debt is gravy, our deficit is profit, our long struggle against incursions of capital from the north to the south of the break-even line is ended.

Or is that a leap already taken by knowledgeable moneypersons, dating at least as far back as, I don't know, around 1984?