A shift in White House economic views?

Gone from the Reagan administration are the more extreme voices whose economic theories have failed to perform as the White House had hoped.

Martin Feldstein, the President's nominee as chairman of the Council of Economic Advisers (CEA), summed up in one sentence his own views:

''Extremists among both the supply-siders and monetarists,'' Feldstein told a Senate hearing, ''who predicted that inflation would be reduced without raising unemployment have been decisively proven wrong.''

A combination of events since Mr. Reagan took office - his own fiscal policies, coupled with a sharp deterioration of the economy - have conspired to push the President toward less radical economic policies.

One sign was Reagan's embrace, albeit reluctantly, of a $98.3 billion tax increase designed to reduce future budget deficits.

The President, nonetheless, still clings to several of his original convictions, against which his advisers stumble - and around which they have somehow to work.

1. Reagan insists that the third round of his tax-cutting program - a 10 percent income tax cut on July 1, 1983 - unfold on schedule.

While still a Harvard professor, Feldstein urged that the third round tax cut be postponed, as a way of narrowing the widening gap between the government's income and its spending.

Now, as the President's top economic adviser, Feldstein may have to mute his earlier view because of Reagan's adherence to the tax cut.

As matters now stand, tax revenues collected by the government will shrink to about 19 percent of the gross national product (GNP) by 1985, while spending will consume 23 percent. Many economists say they believe this provides a built-in recipe for record deficits.

2. The President supports continuing huge increases in defense spending and opposes any significant cutback of that growth.

A growing number of legislators claim that the defense budget will have to take its share of cuts if budget deficits are to be brought under control.

This is especially true since, according to no less a Republican stalwart than Sen. Bob Dole of Kansas, social programs have been slashed far enough for the time being. Senator Dole wants to give such programs a rest.

3. Reagan concedes no causal relationship between lower inflation and rising unemployment.

In a radio address Sept. 25, the President said it was the ''most cynical form of demagogery'' to suggest that his anti-inflation policies had thrown people out of work.

In fact, analysts agree, any administration's anti-inflation policies - if vigorously pursued - would result in higher unemployment.

The President spoke shortly after Feldstein, in his Senate testimony, had drawn a direct link between rising unemployment and lower inflation.

Experts of both political parties still grope for a way to reduce inflation without slowing down the economy so much that people lose their jobs. Conversely , no way has been found to create jobs rapidly through stimulative spending without reigniting inflation.

4. Reagan, despite protests by allied governments, invokes sanctions against European firms selling US-based technology to the Soviets for construction of a natural gas pipeline from Siberia to Western Europe.

The President's professed motive is to put pressure on the Kremlin to modify martial law in Poland. Apart from this, some administration officials - notably Defense Secretary Caspar W. Weinberger - want to deny the Soviets billions of dollars worth of hard currency they would earn through gas sales to Western Europe.

The issue drives a deep wedge between the Unitled States and key European allies, where the pipeline means thousands of manufacturing jobs for depressed economies and, eventually, reduced European reliance on Middle Eastern oil.

Observers assume that Secretary of State George P. Shultz opposes the use of trade sanctions as a diplomatic weapon. This was his expressed view when he was president of Bechtel, a giant US construction firm, before joining the Reagan team.

Behind the scenes, Mr. Shultz and other administration officials are searching for an alternative way to put pressure on the Soviet economy, without punishing US and European firms through sanctions.

So far, however, no compromise is in sight and the transatlantic debate grows more acrimonious.