Practitioners of the journalist's profession are supposed to be skeptics, believing none of what we hear and only part of what we see.

That general attitude notwithstanding, I have found, in trying to make sense of events, that it works just as well to assume that public figures mean pretty much what they say -- at least when they are espousing general principles.

In short, I am willing to accept that President Reagan believes what he has been saying all along, and what he repeated -- at least by implication -- in his inaugural address: that a dynamic, unfettered economy will, by itself, bring America's excluded minorities into the economic mainstream.

I accept that he believes it. I also think he is wrong.

The first four years of his administration were, on many levels, more sucessful than I would have dreamed. Politically, he is in excellent shape. Our European allies (at last) are finding him to be more reliable than his predecessor and, being more predictable, easier to deal with. Even the Soviets recognize him for a tough opponent. His "Star Wars" idea, for all its theoretical flaws, has already proven to be an important chip in the arms negotiations. The economy (save for the dark cloud of deficit) is measurably better than he found it -- except for black Americans, whose status actually declined during the first Reagan term.

While he finds chagrin in that last fact, I don't think he has yet come to grips with its implications. He may believe, as he said Tuesday, that "a great national drive to tear down economic barriers and liberate the spirit of enterprise in the most distressed areas of our country" will be sufficient to bring blacks into the recovery. But I don't think he fully under stands -- maybe no one does -- the nature and pervasiveness of those economic barriers.

The barrier that is most obvious to blacks -- racism -- is the one least obvious to the president. He knows about favoritism and insider deals, but does he believe that outright racism of the sort blacks constantly allege is a significant factor in black business-formation and business-failure rates or in black joblessness? He seems not to, which may be why his administration has had so little enthusiasm for the protected markets of 8(a) set-asides or other sorts of affirmative action programs.

He may be starting to understand, thanks to his recent meeting with the newly formed Council for a Black Economic Agenda, that the absence of access to venture capital is one critical barrier. But does he understand that untargeted policies to free up venture capital may not be particularly helpful to black entrepreneurs?

Indeed, the importance of targeting in general is something the president has been slow to learn. The business tax cuts of his first term, for instance, were very helpful, particularly to big businesses. But if they had been targeted toward new, small, labor-intensive enterprises, they might have done double duty.

Reagan's inaugural address echoed two newly popular themes: the need to move the disadvantaged from their dependency and the desirability of making America an "opportunity society."

Both themes deserve support -- but carefully. It's one thing to say that government welfare programs, by trapping poor people in their poverty, have exacerbated their problems; quite another to conclude that, therefore, the best thing the government can do for the excluded -- that desperate and growing underclass -- is to get out of the way.

The nature of the help that is needed is a proper subject for debate. The fact that help -- specific, targeted help -- is needed ought to be beyond question. "We must," he said Tuesday, "do what we know is right, and do it with all our might."

Let's hope he means it.