THE ROMANS had a word for it, gravitas -- meaning gravity, seriousness, weight. You say it of a serious person. But you do not mean by this a person who is without humor -- humor surely goes with seriousness. Rather you say it of a person who knows what really matters and who, consequently, really matters himself. You say it of a person like Joseph Kraft, our columnist of 20 years, who died at the age of 61 on Friday. Above all Joe Kraft had gravitas. He was in the rare, best sense a serious man.

Mr. Kraft had another attribute that, to be both polite and somewhat cryptic about it, perhaps not all his fellow journalists shared. He was amazingly generous to and about his colleagues, especially many of the younger ones whose work he greatly respected and encouraged and who, in turn, were deeply devoted to him. This generosity was not something that existed apart from his work, as a kind of cultivated virtue or side-line human experience. Rather it reflected precisely Joe Kraft's abiding commitment to journalism and his ferocious, even obsessive, pursuit of the excellent in this chosen line of work. He wanted to be better himself and he wanted others to be better too and he did everything in his power to bring about both results. It did not occur to him to be stingy or secretive or acquisitive or self-protective in relation to his colleagues. He gave them everything he could.

It has been said of Joe Kraft repeatedly in the past couple of days that he was a direct descendant of the great political columnists like Joseph Alsop and Walter Lippmann and James Reston who distinguished and dominated the middle years of 20th century American journalism. And in many respects this is true. Mr. Kraft's prodigious work, his mastery of the head-breaking issues of national and international life, his devotion to subject, his horror of the superficiality and exhibitionism of much modern journalism, his insistence on having something more than merely an opinion to offer his readers -- all this made him part of a particular honorable tradition.

He didn't do a buck and wing. He worked like a dog and gave you his best analysis. He moved easily among the people who were making the large decisions and also among those in the ranks who often had more to tell than their bosses did. He had some big successes with individual columns; he sometimes made news in that space at the lefthand top of the op- ed page, and, like all good columnists, he was assiduously plagiarized by his pals. It was Mr. Kraft, you may have forgotten, who put the term "middle American" into the journalistic vocabulary, though not he who drove it into the ground.

Our reservation about the insistence on seeing Mr. Kraft in terms of earlier titans of the trade, especially seeing him as the man who would or did replace Walter Lippmann, is this: it doesn't acknowledge what Mr. Kraft himself had become in his own right. You will notice we have dwelt on Mr. Kraft's syndicated newspaper column at the expense of his other writings -- his books and magazine articles -- and his academic enterprises, important as they were. That is because the column was at the core of what Joe Kraft did and because he did it like no other. The question is not: whom did Joseph Kraft replace as a columnist? The question is: who can replace him?