Is it too early to judge the performance of America in the 1980s? Of course not; we're doing it all the time. There is a steady flow of criticism, generally from the left, the most substantial of it in the form of books, and now it's beginning to pile up: Barbara Ehrenreich's "The Worst Years of Our Lives," Bryan Burrough and John Helyar's "Barbarians at the Gate," Paul Kennedy's "The Rise and Decline of Great Powers," Kevin Phillips's "The Politics of Rich and Poor."

Such is the clamor that Commentary magazine has published a symposium in its September issue, having invited 19 persons to comment on whether the decade was a triumph or a disaster. What alarms the magazine, of course, is that it speaks for the neoconservatives, whose political program, including "supply-side economics," ushered in the decade.

The issue makes fascinating reading. But what it really illustrates is the big difference between gut opinion -- both right and left -- and the serious storytellings research from which we will ultimately write our history.

Certainly the Commentary panelists frame the issue well enough. James Neuchterlein, editor of First Things, a right-wing journal of religion and public life, writes: "American liberalism has in fact never recovered from the Great Society. ... Activist government was no longer in the public mind an unambiguous good thing; it had become, at best, uncertain and problematic, at worst the unwitting source of our deepest problems. It was Ronald Reagan's achievement to raise all this from the level of inchoate intuition to conscious perception."

And Christopher Lasch, professor of history at the University of Rochester, speaks for the left when he writes, "The collapse of communism represents a victory, of sorts, for the West -- but not much of a victory for the United States and certainly not for the 'prevailing ideas and policies of the American '80s.' The real winners, as everybody knows, are the West Germans and the Japanese, who owe their power and prosperity to a combination of circumstances having nothing to do with the 'policies of the American '80s.' While the United States and the Soviet Union were exhausting themselves in the production of armaments, West Germany and Japan, unburdened by competition in the arms race, rebuilt their shattered economies and cultivated the arts of peace."

Moreover, there are great little reminders scattered here and there of battles that the rest of us have forgotten. Robert Coles looks back on Helen Caldicott, for example, the nuclear freeze activist whose Paul Revere-like warnings that thermonuclear war was imminent in the early 1980s puzzled a generation of schoolchildren. He quotes a factory hand from Framingham, Mass., who had listened to Caldicott on his car radio:

"She's half crazy, and so are some of you who hold her up as the wisest one around. You can hear it in her voice, not just her words -- all that scary talk, all that screeching! And if you disagree with them, they point fingers and shout and try to tell you that they're smart and you're dumb, and they're right and you're -- well, you're not just wrong, you're sick!" There is a strange silence from such people now, Coles notes.

What is most striking, however, is that there are relatively few numbers in the Commentary exchange, and what there are have been produced mainly for rhetorical effect. No economist is included in the group, though there are a political scientist (Charles Murray), a lawyer (Robert Reich), a sociologist (Paul Starr) and a couple of journalists (George Gilder and Tom Bethell) who write mainly on economic topics. This alone tells you something about where the neoconservatives are coming from after a decade of debate.

But more largely, it demonstrates something worth knowing about New York intellectuals: They are usually more interested in banter -- some of it rhetorically very powerful -- than in pinning the thing down. The Commentary selection offers an oil-and-vinegar selection of extremes.

It is in this sense that an article by Andrei Schleiffer and Robert W. Vishny on "The Takeover Wave of the 1980s" in an August issue of Science magazine offers an interesting contrast. Schleiffer and Vishny are professors at the Graduate School of Business at the University of Chicago; together with Kevin Murphy of Chicago's economics department, they are jokingly known as "the trio" by the younger generation of technical economists, the result of their collaboration on an influential series of policy-oriented articles in scholarly finance journals. They are among the cream of the crop of a generation of young economists who have stepped forward to the center of the debate over America's place in the world economy.

There can be few people in America who don't have friends or family who were affected by the merger boom of the 1980s. Hostile takeovers and leveraged buyouts, "Saturday night specials" and bust-ups were as much a part of the decade as were turn-of-the-century trusts, 1920s oligopolies or 1960s conglomerates. So what happened? A decade of unparalleled greed?

Not exactly. Schleiffer and Vishny argue that, spurred by the easy availability of funds and a rethinking of the antitrust laws, the principal effect of the merger boom seems to have been to unwind the conglomerate movement of the 1960s. That movement, fostered by antitrust rules that were stringent to the point of being otherworldly (a combination that moved market share from 5 percent to 7 percent of a narrowly defined market could be nixed by the feds), resulted in growth-oriented corporate executives buying companies in unrelated industries about which they knew nothing, instead of paying out earnings in dividends. Kraft cheese took over Eveready batteries; Revlon moved aggressively into health care. Not surprisingly, the conglomerates generally didn't prosper.

Thus, the merger movement of the 1980s acted mainly to move assets out of conglomerates and toward more specialized users of capital, Schleiffer and Vishny write. The presumption is that less diversified companies can manage their businesses more effectively and so increase American competitiveness in the world economy. What's more, the three most common objections to takeovers don't really hold up, the Chicagoans say. Great concentrations of market power haven't arisen, job losses are confined mostly to white-collar employees (among whom significant lengthy employment hardly exists), and the widely feared reductions in investment in research and development are exaggerated, they say. They take sharp issue with Massachusetts Institute of Technology's "Made in America" report's conclusion that pressures of debt and financial markets prevent American managers from focusing on long-term projects. Although "the jury is still out" on the merger wave, they conclude, the evidence recommends "cautious optimism."

Now it is true that Schleiffer and Vishny haven't persuaded everybody of the accuracy of their critique -- just the editors and referees of Science magazine. And it is true, too, that the merger movement is just one aspect of the American '80s. There is the matter of widening inequality, of women's entry into the workplace, of excessive debt and financial fragility.

But careful people will work these questions through -- and of course the meaning of the last chapter will take on more significance as we travel more deeply into the next chapter.

In the meantime, there will be more nimble posturing, intellectual skywriting and yes, well, screeching.

David Warsh is a columnist for the Boston Globe.