To oppose the assumptions and everyday reality of a particular world, yet be among the men and women who enjoy its benefits - those accorded to the substantial upper bourgeoisie of, say, Johannesburg and Cape Town - is at the very least to know and live uneasily, maybe at times shamefacedly, with irony as a central aspect of one's introspective world. At what point is one's thoroughly comfortable, highly rewarded life as it is lived from year to year the issue - no matter the hoped-for extenuation that goes with a progressive voting record, an espousal of liberal pieties? Put differently, when ought one to break decisively with a social and political order, put on the line one's way of living (one's job, the welfare of one's family)?
In past novels, notably ''Burger's Daughter,'' Ms. Gordimer has asked such questions relentlessly of her own kind and, by extension, of all those readers who share her color and status in other countries less dramatically split and conflicted. Now, in ''My Son's Story,'' a bold, unnerving tour de force, she offers a story centered around the other side of both the racial line and the railroad tracks - yet the dilemmas that confront her characters are at heart very much like those that plague affluent whites, insofar as they allow themselves to oppose the entrenched authority of the South African