Extrapolations

Although science fiction is not prediction, speculative fiction does include both technological and sociological extrapolations which can also be found in some works of non-fiction and even in a few works of contemporary fiction. See Predictions.

Poul Anderson's sf not only includes both "space opera" action-adventure fiction and serious speculative fiction but also incorporates both of these antithetical sub-genres into a single future history series. Rereading a very different author's twentieth century contemporary novels (see the above link), I am surprised to find in his texts not only a specific social prediction but also one that directly addresses the early twenty first century, here and now.

Someone said that the republic of letters is one. Whether a novel is nostalgic or anticipatory, it addresses humanity. Thus, common themes emerge.