His criticism, while acknowledging that morality is historically relative, was thus values-based. "Writers can make men "feel", not merely see, the values that endure." Believing that too many modern writers encouraged men and women to flee to unreason, decadence and barbarism, he condemned the "trahisons des clercs" of the twentieth century, and used his lectures and writing to campaign for a responsible use of intellectual freedom. "One may question whether real civilisation is so safely afloat," he wrote in his last published letter (1966), "that we can afford to use our pens for boring holes in the bottom of it." The writer or artist serving up "slapdash nightmares out of his Unconscious", "in an age morbidly avid of uncivilised irreticence", not only exhibited his own neuroses, but fed neurosis in others. Literary critics, too, had to take more responsibility. "Much cant gets talked," he noted of the Structuralists, "by critics who care more for the form and organisation of a work than for its spirit, its content, its supreme moments." The serious note in his criticism was counterbalanced by wit and urbanity, by lively anecdote and quotation, and by a gift for startling imagery and epigram.