There's a new set of contradictions plaguing the economy:

On one hand, the personal income of Americans is rising sharply. The average hourly wage in the United States has risen 40 per cent in the past five years - one of the fastest increases on record.

At the same time, workers' purchasing power is only barely keeping pace. After adjustment fo inflation, an average hour's wages buys no more today that it did in 1972.

As a result, while workers generally may be earning more in dollars than they did five years ago, in many cases they're enjoying it less.

These statistics lie at the heart of a fundamental change that has overtaken the U.S. economy in recent years - one that could affect every American for the next decade or longer:

What used to be considered a stagering price pace in 1969 and 1970 - an inflation rate of 6 to 6 1/2 per cent or higher - is regarded today almost as normal. Inflation now is triple its pace of the early 1960s and is likely to stay that way for years to come.

Why is inflation continuing to rage so heatedly, despite two major recession periods that ordinarily should have dampened price increases?

Ask almost any economist, and the answer that comes back is: wages.

Over the past 11 years, the U.S. worker has had to push for sizable wage increases just to stay even with inflation. And, as a result, wage gains have become built into the nation's inflation spiral - and are making it more difficult to wind down.

To be sure, there's little real argument that large wage boots have been justified in recent years. Workers have been hit by a series of inflation "shocks" that have sent prices rising 94.3 per cent since 1968. Even with the gains in wage levels, purchasing power has barely remained even.

First there was the Vietnam war, which sent prices spiraling throughout the economy. Then in 1972 and 1973 food prices rose sharply. The gains workers made went in large part to farmers. Finally, in 1974, oil prices broke loose, and new wage gains were sapped by the energy companies.

The problem is, the catch-up game has continued for so long that wage gains now are "built in" to the overall inflation spiral - feeding the price surge as well as just keeping pace. Unless the cycle is broken somehow, inflation could remain at 6 per cent or higher almost indefinitely.

If the 6 per cent pace were to continue for 10 years, the impact would be dramatic. A haircut that costs $4.50 today may run as much as $8 in 1988. A new car, now $5,200, could cost $9,300 then - without any extras. And a $399 appliance could sell for $687.

Indeed, some forecasters already are predicting that inflation will edge up to 6 1/2 per cent later this year. After that, it's anyone's guess. But, laments Arthur M. Okun, the former Johnson administration economic adviser: "Most of the things you see on the horizon are things to make inflation go up further."

he reason wage inflation is so sticky is it's harder to deal with than any other kind.

Unlike behavior trends in prices, wage patterns don't shift quickly in response to changes in economic conditions. Labor contracts usually are witten to cover two and three periods. So wage boots agreed on last autumn, for example, can't be alterted until 1980.

Moreover, in many key industries, wage-and benefits packages for one group of workers are linked by tradition to those of a so-called "pattern-setting" union. For example, the wages of rubber workers historically have been pegged to those of auto workers. When one gets a 7 per cent boots, the other follows.

Wage increases are important because, with labor making up the bulk of most production costs, they have a direct impact on overall business costs. When wages rise rapidly for a long period, these cost increases become part of the economy's price structure. As a result, prices simply can't come down.

While wage increases have moderated slightly in the past few years, they still are rising sharply by historical standards. Since 1968, the Labor Department's adjusted hourly earnings index - considered the best measure of wage patterns - has jumped an average of 6.9 per cent.

And when fringe benefits are included, the figures show total compensation per manhour rising at an uncomfortable 8 per cent rate. With overall productivity gains - that is increases in worker efficiency - edging up only an average 2 per cent or so, that implies a price pace of 6 per cent of more.

Moreover, there's no indication that the wage surge will moderate any in the next few years. Most labor analysts believe wages will continue rising at a 7 to 8 per cent pace for at least three more years - and possibly longer effectively blocking any chance that inflation will subside.

The situation poses a dilemma for the Carter administration, which promised during the campaign to bring inflation down further, but now has discovered that - because of the wage spiral - the feat is more difficult than policy makers thought.

While Carter has followed relatively austere spending policies - particularly fora liberal Democrat - it isn't hedping to slow prices any. (A decline in the federal deficit may help interest rates somewhat, but it won't slow the wage spiral.)

Even the Federal Reserve Board's recent credit-tightening isn't affecting the wage surge any. Economists point out that wage surge any. Economists point out that wage increases continued high even when unemployment soared to 9 per cent in 1975. High jobless rates traditionally have slowed wage increases some, but this time it hasn't worked.

What some economists say is needed is a program to help change business and labor attitudes on wage and price increases - in effect a form of "incomes" policy, in which both sides agree for the good of all to hold down their demands.

But the administration has run into fierce opposition on this every time it even has suggested such a proposal. The White House drew up a plan last spring that would have asked business and labor to notify the government in advance of any big price increases - but withdrew it hurriedly after protests from both sides.

And the administration recently rejected a proposal by Okun to give tax incentives to companies and unions that agree to moderate their wageprice demands. Officals now are gunshy about the whole affair.

If anything, the administration's own actions have done more to exacerbate inflation than to ease it. The list includes a stiff new increase in Social Security payroll taxes, a higher minimum wage, a big boost in farm price supports and a sharp devaluation of the dollar.

Combined with a possible run-up in farm prices later, the moves could reverse some of the progress made on the price front last autumn, and push the inflation rate up to 6 1/2 per cent or more by year's end. In any case, economists say, prices aren't going to abate any.

If inflation stays at 6 per cent, can the nation learn to live with it?

Economists differ on that score: Joel Popkin, price trends specialist for the National Bureau of Economic Research, says it will "take more than a few years to get used to" a permanent 6 per cent rare, but "10 years from now, we may say it hasn't been bad."

but Okun doubts strongly "that anybody really can adjust to it." To put everything back into balance at that rate, he says the government would have to provide automatic inflation adjustments for everything form tax rates to corporate accounting procedures - a system that would become a "base" on which further increases would be staked. "Can anybody really believe that would be the last turn of the rachet? he asks rhetorically.

Carter administration officials agree that allowing inflation to continue at a 6 per cent pace "isn't a viable solution," but they're stumped over what to do to change the situation. "Anything we try that promises to be effective isn't achievable politically," one policymaker complains.

In the meantime, a 6 per cent inflation rate seems to be a fact of life - not only for today, but for coming years as well.

In another decade an $8 haircut may seem like a bargain.