I PREDICT THAT someday a lot of our modern social scientists are going to drown in their own banality. Some are already standing in it chin-deep, and the wiser ones are on tiptoe, murmuring: Don't make waves.

My bilious generalization is, as usual, grossly unfair to the real thinkers in that academic realm -- and there certainly are a good number of them -- but I am agitated by the continuing literature of inequality. The latest entry, for example, is a book, "Who Gets Ahead?" (Basic Books, New York, 1979), and here is how its principal author, Harvard sociologist Christopher Jencks, summarized the findings in a learned magazine interview.

"Q: Who does get ahead? Can you sum it up for us non-statisticians?

"Jencks: Well, the short answer is that people who have one or another kind of advantage get ahead. But the big conclusion of the book is that no one advantage that you can identify explains any enormous amount. There are lots of little advantages. If you happen to have all of them, your chances are much better than if you have none of them."

What else can one say but "Wow"? Life is complicated, as well as unfair. If you are brainy and beautiful, that's better than dumb and ugly. If you have a rich daddy, that is better than poor. If you obtain a doctorate from Harvard, that's better than dropping out of high school. Wow.

Thus do the great universities and think tanks and government agencies spend small fortunes in computer and time to discover what ordinary people already know. For some reason sociologists seem to believe they have discovered something new when they have assigned a specific percentage to an ancient influence in life.

This would be amusing and harmless except that we know from past episodes that the authoritative conclusions are often distorted (sociologists probably prefer "extrapolated) into public arguments over government policies. All of Jencks' statistical subtleties, mark my word, will soon be boiled down again by some statesmen, too busy to read themselves, into a simple conclusion: Schooling doesn't matter that much in helping poor folks, so why bother?

I have been reading various academic studies of equality for nearly 15 years, starting with the landmark controversy over the Coleman Report in 1966, and while the dissection of inequality has become a minor industry on the best campuses, I could never quite put my finger on what seemed wrong about these studies.

Now I think I have stumbled on part of the answer, perhaps a fundamental flaw in the way these social scientists think about us, the American people.

In one sense, these are noble question the academics ask: Is this a just society?Is there equality of opportunity, as our American mythology supposes, or is a rigid class system hiding behind the myth? To pursue that question, the academics must first invent perfect worlds in their heads -- an imagined society where opportunity is not merely vast but truly "equal" -- and I think this is where their work departs from our reality, the America we know from our lives and our aspirations.

In their complicated attempts to calculate precisely how much of which factors lead to success, better jobs and incomes -- you know, justice is 38.674 percent, morality is 26.1898 percent, politics is 44.547 percent -- the scholars divide things into "good" and "bad" influences. Schooling, for example, is good theoretically. Family background is bad. Of course, they do not apply these crude labels in their studies -- after all, they are "scientists" -- but anyone with the fortitude to read through these works will see the inference that family background is bad because it contradicts our myth of equal opportunity. We are supposed to worry, maybe even feel guilty.

What's wrong with this picture? What's wrong is that most Americans, maybe all Americans, probably all human beings (including social scientists, at least in their private lives) do not address life in those terms. The social science picture may look sound in the lab, but in real life it looks simple-minded, for it ignores a basic component of the human experience: the desire to pass on some sort of inheritance to one's children.

I never met a mother or father who didn't believe in this. I never met any parents, rich or poor, who didn't try to give something of value to their children, however modest or irrelevant, who didn't derive enormous satisfaction from the idea that the children will inherit from them. It is, after all, an age-old motivation in life, a basic human purpose.

Yet the social scientists would repeal that component in our lives in order to create a perfectly fair society. Everyone would have the same random chances, regardless of family. A middle-class kid would wind up poor as frequently as a rich kid does or a poor kid. Nobody would inherit any status in this theoretical land.

I am rather confident that this is now how Americans of any persuasion conceive equal opportunity. The stark illustration is the experience of American black families, principal subjects of the inequality studies, who have long suffered from the random injustice and cruelty of life without family inheritance. Thanks to racial discrimination, black families have endured what sociologists David L. Featherman and Robert M. Hauser call a "perverse form of opportunity" -- black parents had great difficulty passing their rung of the ladder onto their children.

Featherman and Hauser, authors of an important study of economic mobility from father to son, describe the situation in 1962: " . . . the circumstance of high social origins could not be coverted into black sons' social advantage as easily as among whites." But their study ("Opportunity and Change," Academic Press, New York, 1978) then compares the 1962 findings with those from more than 20,000 workers in 1973 and comes up with modestly hopeful news -- the inheritance of status is increasingly among black families. In other words, if a black family is middle class, the odds have improved that sons and daughters will retain that status -- instead of falling randomly to the bottom.

I don't want to overstate this sign of progress, because there obviously is still a substantial gap between whites and blacks in terms of inheritance -- a gap that reflects the enduring fact that most black Americans still dwell on the lower rungs of the ladder. Featherman and Hauser, in the ponderous and cautious language of their trade, state it this way:

" . . . Black men would not capitalize upon even the modest resources that their families had accumulated. Most sons, whether from farm or from white-collar 'stock,' were destined for lower manual jobs. The persistence of generations of blacks in subordinate-status positions -- not a consequence of greater status inheritance from father to son but rather a condition of greater disinheritance relative to conditions in the majority population -- was, and is, an American dilemma. But there is some indication that the dilemma has been tempered by moderations of the costs of being black and by new resources for black social mobility."

This social reality, incidentally, provides an insight on human relations for every corporate office in America, every place in fact where white males find themselves working alongside blacks and women, a social development they were not prepared for as little boys. I don't think it's any secret that the white males tend to look at the newcomers and says to themselves: Boy, have you got it made -- to be black and talented in the 1970s means you can write your own ticket. The blacks, however, often seem (again, through the eyes of their white colleagues) to be inordinately skeptical, cautious, even distant or insecure.

This history of disinheritance among black families, I suspect, contributes to our mutual misperceptions and failed understandings. The white boys grew up in family ethos that said, okay, the family got you this far, now you take it from here. The black boys, however, grew up knowing from their own experience that the system works crazily for them -- that a black kid whose family provided him all of the "advantages" within its reach could still wind up with a lousy job and a drastically lower income. Racial discrimination means: You're on your own, kid, and the system doesn't care where you came from or how much you know.

The damage of this racial disinheritance, even though it has "moderated" in the last 20 years, may help explain why those blacks -- who seem to "have it made" -- are not quite ready to throw their hats in the air and celebrate.

But my point is that we could no doubt find a social theorist somewhere who would deplore this trend as evidence that black Americans are now beginning to emulate the class structure already present in the white world. I wonder, though, if you can find any black families who feel that way about inheritance. Or Hispanic families. Or Italian or Jewish or Chinese or whatever.

Most Americans probably see these two elements not in opposition, but in tandem -- the social goal of much greater opportunity and the personal goal of helping one's own children advance. To believe in one is surely not to deny the other.Most people see inheritance as a positive contribution to economic mobility to America.

When the social scientists figure out how to incorporate this simple truth in their complicated theories of equality, maybe the computer studies will have more meaning for us non-statisticians. In other words, the "variable" that these studies have to start worrying about more is social scientists themselves.