For Lem, science fiction is a documented form of thought-experiment: a spearhead of cognition.
All else is secondary, and it is this singleness of aim that gives his work its driving power. This is truly "a literature of ideas," dismissing the heart as trivial, but piercing the skull like an ice-pick.
Given his predilections, Lem would probably never have written "people stories." But his rationale for avoiding this is astounding. The mass slaughters during the Nazi occupation of Poland, Lem says, drove him to the literary depiction of humanity as a species. "Those days have pulverized and exploded all narrative conventions that had previously been used in literature. The unfathomable futility of human life under the sway of mass murder cannot be conveyed by literary techniques in which individuals or small groups of persons form the core of the narrative."
A horrifying statement, and one that people in happier countries would do well to ponder. The implications of this literary conviction are, of course, extreme. Lem's work is marked by unflinching extremities. He fights through ideas with all the convulsive drive of a drowning man fighting for air. Story structure, plot, human values, characterization, dramatic tension, all are ruthlessly trudgeon-kicked aside.
In criticism, however, Lem has his breath, and can examine the trampled flotsam with a cynical eye. American SF, he says, is hopelessly compromised, because its narrative structure is trash: detective stories, pulp thrillers, fairy-tales, bastardized myths. Such outworn and kitschy devices are totally unsuited to the majestic scale of science fiction's natural thematics, and reduce it to the cheap tricks of a vaudeville conjurer.
Lem holds this in contempt, for he is not a man