Kurt Vonnegut in the context of "Charles Scribner's Sons"

Postmodern literature is a form of literature that is characterized by the use of metafiction, unreliable narration, self-reflexivity, and intertextuality, and which often thematizes both historical and political issues. This style of experimental literature emerged strongly in the United States in the 1960s through the writings of authors such as Kurt Vonnegut, Thomas Pynchon, William Gaddis, Philip K. Dick, Kathy Acker, and John Barth. Postmodernists often challenge authorities, which has been seen as a symptom of the fact that this style of literature first emerged in the context of political tendencies in the 1960s. This inspiration is, among other things, seen through how postmodern literature is highly self-reflexive about the political issues it speaks to.

Precursors to postmodern literature include Miguel de Cervantes' Don Quixote (1605–1615), Laurence Sterne's Tristram Shandy (1760–1767), James Hogg's Private Memoires and Convessions of a Justified Sinner (1824), Thomas Carlyle's Sartor Resartus (1833–1834), and Jack Kerouac's On the Road (1957), but postmodern literature was particularly prominent in the 1960s and 1970s. In the 21st century, American literature still features a strong current of postmodern writing, like the postironic Dave Eggers' A Heartbreaking Work of Staggering Genius (2000), and Jennifer Egan's A Visit from the Goon Squad (2011). These works also further develop the postmodern form.

Devolution, de-evolution, or backward evolution (not to be confused with dysgenics) is the notion that species can revert to supposedly more primitive forms over time. The concept relates to the idea that evolution is purposeful (teleology) and thus progressive (orthogenesis), for example that feet might be better than hooves, or lungs than gills. However, evolutionary biology makes no such assumptions, and natural selection shapes adaptations with no foreknowledge or foresights of any kind regarding the outcome. It is possible for small changes (such as in the frequency of a single gene) to be reversed by chance or selection, but this is no different from the normal course of evolution and as such de-evolution is not compatible with a proper understanding of evolution due to natural selection.

In the 19th century, when belief in orthogenesis was widespread, zoologists such as Ray Lankester and Anton Dohrn and palaeontologists Alpheus Hyatt and Carl H. Eigenmann advocated the idea of devolution. The concept appears in Kurt Vonnegut's 1985 novel Galápagos, which portrays a society that has evolved backwards to have small brains.