Despite the failure of a similar attempt by Rhodesian whites, South Africa's white minority government seems to be trying to head off black-majority rule here by cosmetic constitutional changes.

The core of this attempt is to grant limited political autonomy to black "states" in a new confederation whose constitution will be based on a division, not sharing, of power.

This has been made clear in speeches by Prime Minister Pieter W. Botha and his ministers as the country prepares to write a new constitution without black participation.

Critics have charged that Botha's effort is doomed to fail. Preparing a new constitution without the blacks, one Afrikaner political scientist said, is the "staging 'Hamlet' without the prince of Denmark."

But to Botha, who is stage-managing change by fiat and stealth, that problem does not seem to matter.

Last week, in his most significant move to back up his comments about the need for reform in South Africa, Botha unveiled plans to work out a new constitution in which blacks are to play a minor walk-on part, if that.

The proposals call for the establishment of a president's council made up of 60 Colored (mixed race), Indian, white and Chinese representatives to discuss a new constitution. Blacks will have their own separate body, which will consult with the president's council. Both groups will have only advisory powers to the white-minority government, the final arbiter of the new order.

Botha's commitment to reform, an image he has cultivated for himself and his administration, may thus encompass gradual movement away from discrimination in the economic and social spheres, but its horizons do not yet embrace a solution for this country's fundamental problem -- the white minority's political domination over the black majority.

Even Botha's pledge to eliminate discrimination in economic and social areas has grown dim in recent weeks because of the government's failure to show its good faith by repealing some discriminatory legislation in the current parliamentary session.

For example, changes promised last year in laws that prevent blacks from moving freely from one urban area to another have not been made. Botha's pledge to "improve" the laws against interracial sex and marriage, widely interpreted as a hint that he would repeal them, has drifted into obscurity after protests from the right wing of his National Party.

Botha's backers say these developments point to a holding pattern until he has completed major administrative and electoral reforms that will concentrate more power in his hands and enable him to implement changes over objections from the right wing.

Those who take this line say the constitution-writing bodies announced last week are meant to be "public relations displays for the whites" while the real talking -- on changes more significant than Botha can publicly admit -- will take place behind the scenes.

"It's a charade, meanwhile, through the back door. Botha will be getting talks going [with blacks] on dual citizenship in a new confederal body," said one academic who declined to be identified.

"Botha cannot spell out his goals because then his constituency will crumble," he added.

Some Botha sympathizers regard as a "breakthrough" the fact that Coloreds and Indians will sit in the same body as whites.

According to what his critics say, Botha's actions in recent weeks add up to a dangerous misapprehension of the aspirations of blacks, who are demanding equal citizenship and a share in political power commensurate with their numbers.

They say Botha is showing an inability to break out of the confines of apartheid ideology that blacks and whites must be forever separate in South Africa.

"It's wheels within wheels, and makes nonsense of the whole thing," said Nic Olivier, a constitutional adviser to the opposition Progressive Federal Party. It objects to Botha's constitutional initiative because blacks are not in the same body as whites and because the government would not negotiate but only "consult" with the nonwhites.

"There is no inclination to rethink the basic ideology of [Botha's ruling] National Party, which is that through separation conflict can be avoided and peace and harmony achieved."

Botha himself confirmed this.Speaking in parliament, Botha said his administration's policies, to which "there is no alternative," should be taken as "a reaffirmation of the basic principles of the National Party."

"I do not believe in a unitary state or in a unitary society. I do not think it will work," Botha said. "I am asking for the establishment of constitutional structures for the black peoples to make the greatest measure of self-government possible for them and to consolidate the states as far as is practicable."

Police Minister Louis Le Grange backed up Botha's position in a recent speech saying, "The government quite clearly says that the concept of power sharing is out . . . The concept of division of power and the way in which it has to develop are processes that are being worked on."

The government envisions the creation of 10 autonomous states from the homelands or reserves set aside for blacks. These states will then hook up with "white" South Africa in a confederation.

In a frank discussion about why blacks were not included in the president's council, a person close to Botha explained that to do so "would damage the homelands beyond repair. The government wants to encourage the black states in order to reduce the black majority to manageable proportions. It wants an irreducible minimum of urban blacks. Numbers are important, you know," he explained.

It is just this divide-and-rule concept that makes blacks object to all proposals that regard them other than South African citizens. They maintain that the setup envisioned by Botha can never give them a fair portion of political and economic power in South Africa.

In black circles, these developments have provoked a lot of "I told you so's." Referring to Botha's speech, black editor Percy Qoboza said it has "gone a long way to prove those in our country who say that the National Party members can never change, correct. Change to the National Party simply implies not moving away from apartheid but dressing up apartheid in the latest fashion while retaining its horrors."

Botha's speech was also a rebuff to the more reform-minded section of his party whose allies are the Afrikaans-language press. "There is disappointment in the verligte [enlightened] wing of the party," said one Afrikaner editor who has been pushing for faster and meaningful reform in his paper, especially since the victory of former guerrilla leader Robert Mugabe in Zimbabwe. "But there is also pleasure among the hard-liners," he added.

The government's immediate problem will be finding Coloreds, Indians and blacks to serve on the new advisory councils who will not come from the ranks of those regarded as "sell-outs" and "Uncle Toms" by their own communities.

"We cannot accept it," Colored leader David Curry said of the president's council, "because it doesn't accept blacks.

"South Africa's problem will be solved when the African problem is solved. It's useless to make deals with Coloreds and Indians and Chinese. For the Coloreds it's the old story of 'Come in, said the spider to the fly'," Curry said.

A close adviser to Botha, who did not want to be identified, acknowledged that this would be the "first hurdle" to the prime minister's new initiative.

"Maybe it can't be done," he said quietly, looking off into the distance.

"But we've got to try."