Source?

https://www.britannica.com/topic/postmodernism-philosophy

Postmodernism is largely a reaction against the intellectual assumptions and values of the modern period in the history of Western philosophy (roughly, the 17th through the 19th century). Indeed, many of the doctrines characteristically associated with postmodernism can fairly be described as the straightforward denial of general philosophical viewpoints that were taken for granted during the 18th-century Enlightenment, though they were not unique to that period. The most important of these viewpoints are the following.

1. There is an objective natural reality, a reality whose existence and properties are logically independent of human beings—of their minds, their societies, their social practices, or their investigative techniques. Postmodernists dismiss this idea as a kind of naive realism. Such reality as there is, according to postmodernists, is a conceptual construct, an artifact of scientific practice and language. This point also applies to the investigation of past events by historians and to the description of social institutions, structures, or practices by social scientists.

Postmodern philosophy denies naive realism, and with good reason. The fact that reality is socially constructed is a generally accepted truth in sociology and psychology. No serious scientist in the 21st century denies it.

https://en.wikipedia.org/wiki/Naïve_realism_(psychology)

In social psychology, naïve realism is the human tendency to believe that we see the world around us objectively, and that people who disagree with us must be uninformed, irrational, or biased.

Several prominent social psychologists have studied naïve realism experimentally, including Lee Ross, Andrew Ward, Dale Griffin, Emily Pronin, Thomas Gilovich, Robert Robinson, and Dacher Keltner. In 2010, the Handbook of Social Psychology recognized naïve realism as one of “four hard-won insights about human perception, thinking, motivation and behavior that … represent important, indeed foundational, contributions of social psychology.”[5]

Many philosophers claim that it is incompatible to accept naïve realism in the philosophy of perception and scientific realism in the philosophy of science. Scientific realism states that the universe contains just those properties that feature in a scientific description of it, which would mean that secondary qualities like color are not real per se, and that all that exists are certain wavelengths which are reflected by physical objects because of their microscopic surface texture.[19]