PAUL SCOTT: A Life by Hilary Spurling (W. W. Norton: $24.95; 438 pp.). Paul Scott, author of "The Raj Quartet" and many other novels exploring the emotional and psychological displacement caused by British rule over India, once wrote that the writer draws on "the feeling that you are somehow separate from your environment and can't identify with it really satisfactorily--plus the feeling that this inability, far from being wrong , ought to be cultivated." Hilary Spurling, an English critic and author of a biography of the writer Ivy Compton-Burnett, attributes Scott's sympathy for the "outsider" to repressed homosexuality. She doesn't have an enormous amount of evidence to go on, and her discussion of Scott's sexual inclinations is annoyingly coy, but Spurling's revelation lends greater interest to a biography made at times obscure (at least to American readers) by an excess of Britishisms. For the novelist's fans, though, "Paul Scott" is a must, for Spurling delves deeply into the characters that became, in the end, more important to Scott than his own life.