The New Wave emerged in the 1960s, posing a radical challenge to traditional science fiction both on a thematic and aesthetic level. The New Wave writers were more literary and experimental, and their themes delved deeply into the realms of the human condition (tackling topics such as sexuality and psychology)...
The New Wave emerged in the 1960s, posing a radical challenge to traditional science fiction both on a thematic and aesthetic level. The New Wave writers were more literary and experimental, and their themes delved deeply into the realms of the human condition (tackling topics such as sexuality and psychology) rarely explored by earlier science fiction writers such as Clarke and Asimov.
Of the four stories your question addresses, probably the most conventional is "We Can Remember It for You Wholesale." It is a story about technology, in which a man's memories are overwritten (only for it to be revealed that his memories had already been overwritten). However, for Philip K. Dick, the exploration of technology and scientific possibility is far less important than what it suggests about human psychology and identity: what is the nature of memory, and how do we separate real from unreal? Those are critical questions the story addresses.
Then there is Delany, whose short story is explicitly about human sexuality, exploring themes of non-heteronormative sexual attraction, as well as prostitution. At the same time, however, it also addresses themes of alienation and self-loathing in this world it depicts, centered around the sterilized Spacers and the subculture (referred to in the story as frelks) who are attracted to them.
Meanwhile, the last two stories are comparatively more experimental in their literary tone and style. In many respects, Zoline's "The Heat Death of the Universe" stretches the limits of science fiction altogether, as it explores the life of a weary housewife as she teeters on the edge of a mental breakdown. The writing is similarly experimental, with its interweaving of various subject matters and literary tangents, even as it is organized into fifty-four separate numbered paragraphs. Meanwhile, its themes and subject matter, following a disaffected housewife, conveys a psychological realism and sense of reality far removed from science fiction's Golden Age.
Finally, there is Harlan Ellison's "'Repent Harlequin!' Said the Ticktockman," a story that takes refuge in the absurd, distorting reality rather than depicting it in its hyper-stylized depiction of a battle of wills between the Harlequin and the Ticktockman, while envisioning a society that, in its devotion to punctuality, leaves behind any interest in capturing reality or believability as most would comprehend it. Stylistically, it weaves in and out of stream of consciousness writing, even as Ellison inserts his own voice directly into the story, injecting ironic or cutting remarks every now and again, shattering the separation usually maintained between narrator, narrative, and author.
Taken together, you can perhaps observe the spirit of experimentalism and freedom of expression valued by the New Wave writers, and the challenge they posed to traditional science fiction circles.