Consumer culture has almost obliterated the line between the public sphere, where certain images were once proscribed by civic standards of decency, and the private sphere, where images frankly designed to induce sexual pleasure have been tolerated. In this environment, one does not necessarily have to be hostile to pornography as an option in the private pursuit of pleasure to be disturbed by the drift of contemporary art toward what was once deemed the pornographic. The erotic energy of art is certainly one source of its power. This distinction rested, I think, on a deeper one between what Ms. Steiner calls the ''taste for the sublime'' and what used to be denigrated as merely carnal, or prurient, pleasure. Ms. Steiner makes a brave case for contemporary art as still devoted to the ideal of sublimity.
Art has artistic value.
Twenty-three pages later, when Ms. Steiner actually describes Mapplethorpe's photographs as ''pornographic art,'' she makes a telling slip that suggests that the distinction she is trying to preserve has all but collapsed. In the face of this collapse, Ms. Steiner has written a fervent and eloquent defense of the esthetic imagination. Art, she writes, ''serves to open thought rather than close it down. . . . It allows us to understand without assenting, to go over to the other side and still stay home, to be violated and yet in control. It appeals to our freedom and individualism and in the process to our investment in collectivities.