The differences in narrative setting which separate Le Guin's fantasy and her science fiction are tangential. Happy endings are unrealistic and produce comedy like "April in Paris" and fantasy like the Earthsea trilogy. The exile or death of the hero, which is realistic, is the basis of tragedy and of the pressure toward verisimilitude that makes science fiction like "The Masters" or [The Left Hand of Darkness] seem realistic even though the narratives are governed by far-fetched assumptions. What is essential to Le Guin's work is not detail of setting or the type of action, comic or tragic, which she imitates. What is essential is the argument which runs through most of her major pieces, the way in which explicitly in her science fiction and implicitly in her fantasy, she examines the effects of science on individual personalities….
I will hazard the generalization that most science fiction is concerned with the technological consequences of science and hence that when science figures in such work it does so as a source of the setting or of impetus for plot developments…. The themes of [such a] novel do not really involve science. Science, more precisely some hypothetical extensions of current science and technology, provide the furniture of the setting and the impetus of the plot.
