HISTORICAL DRAMAS are difficult to bring alive. Unless the audience has a highly improbable passion for historical facts, the playwright has to make some effort to connect his theme with modern concerns. In addition, he has to create some kind of tension other than the what-happens-next variety, since the plot will usually be familiar.

In Brecht's Galileo, the modern concerns are there. References to the starving Italian peasantry make clear Brecht's political leanings, and in emphasizing the possible dangers of scientific inquiry, he invokes the Einstein/Oppenheimer dilemma. But these issues have too little to do with the progress of the play to hold it together. The political speeches seem like incidental inserts, and by the end of the play Brecht seems to have dropped the issue of science's dangers in his concern with Galileo's integrity.

Theoretically, our sympathy with the characters could produce a certain amount of dramatic tension even though we already know the final outcome. Unfortunately, the Loeb production lacks even that tension. Part of the failure can be blamed on Brecht's dialogue, which has a stiffness that marks his characters as unreal figures, as mere vehicles for statements. To a large extent, however, the fault lies with the uneven acting. George Hamlin, as Galileo, has a powerful, expressive voice, but he seems to have trouble remembering his lines. Some of his slips and stammers fit in with the image of an absent-minded, introverted scientist, but too many of them are obvious mistakes. His daughter Virginia, who should earn our sympathy when we see her father callously neglecting her interests, puts us off with her annoying, uniform breathiness. William Schwalbe has some appeal as the eleven-year-old Andrea Sarti, but in the second act he is replaced by an older actor, whose greater professionalism is countered by a loss of vitality.

EASILY THE MOST inventive aspect of the production is Franco Colavecchia's set. It is starkly unpretentious, and at first glance seems almost too bare. But the backdrop, seen through three rectangular frames, turns out to be a series of projected slides that change with every scene. This clever technique, highly appropriate to the play's emphasis on sight and the technology of seeing, works especially well in the scenes with perspectives of grand interiors. Unfortunately, only those who are sitting smack in the middle of the theater get the full effect.

The costumes are so elaborate as to be distracting. Charles Weinstein, as Matti the iron founder, provokes laughter from the audience on his first entrance purely because of his plumed hat and bizarre purple outfit. But we're so busy looking at his clothes that we miss the significance of his lines. The same thing happens later in the play, when Peter Kazaras' strong speech as Pope Urbino is marred by the attention devoted to the progress of his complicated toilette.

For a play that is ostensibly about science, Galileo takes an irritatingly simplistic view of scientific discovery. After hearing a brief description of a telescope, for example, Galileo immediately constructs his own telescope out of two lenses, two breakfast buns, and an old book. Most of the experiments he conducts are embarrassing in their inanity. Just because he is dealing with the infancy of empirical science is no reason for Brecht to reduce science to an infantile level. The proof that this is unnecessary comes as early as the first scene, when Galileo explains his theories to the young Andrea. Perhaps because he is speaking are truly imaginative, the excitement of scientific discovery is more believable here than in any later scene.

BRECHT'S INABILITY to convey science convincingly is not just an irritating drawback: it is a central flaw in this work. How much faith can we place in a man's evaluation of scientific progress if he seems to have no conception of what science is? Like this whole production, Brecht's script lacks a tone of authority. The players and the playwright seem equally uncertain about what they are trying to do, and therefore equally incapable of achieving it.