Social security has to change. There is no doubt about this in the mind of anyone who has ever given the system any study.

But talk of change throws beneficiaries into a panic ("Will my check be cut?"). It also weakens support for the system among younger taxpayers, who think they won't get fair value from their contributions.

In order to create a clam and rational climate in which changes can be openly discussed, former Social Security Commissioner Stanford Ross has these suggestions:

(1) Congress should pass a law saying that Social Security benefits, like interest on the national debt, will be paid from general tax revenues if payroll taxes ever prove to be insufficient. Today's moral obligation to pay benefits would then become a legal obligation. Such a law, Ross believes, would go a long way toward calming fears that, some day, Social Security might run dry.

(2) It should be made perfectly clear, by law or by constant reassurance, that no one now receiving Social Security benefits will ever have his or her check reduced. Nor will those near retirement have their hopes pulled out from under them. Changes will be made gradually. over 25 or 30 years. And, those changes will principally amount to slowing the scheduled growth in benefits rather than scaling them back from present levels.

The Social Security system of the 21st century (a brief 20 years away) lies partly disclosed in a new report by the Advisory Council on Social Security, which studies the program every four years and recommends new directions. That passions on these matters run high is evident from the copious footnotes, where a shifting cast of council members notes constant and vigorous disagreement with majority position. But in general, their thinking runs like this:

Remove Medicare from Social Security, and finance it with income taxes. That portion of your payroll tax that covers Medicare (1.05 percentage points, of an employe's 6.13 percent contribution), should be reallocated -- half to help finance other Social Security benefits, half to lower payroll taxes and eliminate scheduled increases for 1981 and 1982. Every advisory council since 1965 has made this general suggestion; sooner or later, Congress will accept it.

Insulate Social Security from the effects of recessions. A near-crisis occurred in 1973-74, when high unemployment cut payroll tax collections and vastly reduced the Social Security Trust Fund. Another severe recession would do the same. Says the council: Social Security should be able to borrow from general revenues if trust funds fall too far.

Slow the rate of increase in earnings subject to Social Security taxes (this year, taxable earnings levels rise to $25,900, from $22,900 in 1979). This action would slow the rise in benefits due higher income people, but leave them more money for private savings.

Win back the support of young, higher-wage workers, with a benefit structure that gives them their money's worth. Each added dollar of employe taxes, says the council, should generate at least an added dodllar of benefit protection, plus interest. If this theory were put into practice, it would principally mean better benefits for people who remain single.

Give full-time, low-wage workers, who can't afford to save for their own retirement, a guarantee that their Social Security income won't fall below the poverty level. This guarantee should not, however, be extended to people whose low wage accumulation results for part-time or intermittent work. (Today's benefit structure favors persons who work less than full time.)

At least half of your Social Security income should be subject to tax. This would create a rough parity between Social Security and private pensions, where the portion contributed by the employer is taxable when received.

Gradually raise the retirement age to 68, perhaps by two months a year beginning with the year 2000, and reduce opportunities for retirement before age 65.

Begin a general discussion of income-sharing between husbands and wives, wherein Social Security credits would be pooled in marriage and split in divorce. This is by far the most radical of all the ideas proposed -- and one you'll be hearing a lot more about.