Postmodernists believe that society (economics, dominant races and genders, politics, etc.) has tainted the language and definitions we use and basically everything we’ve come to know as “knowledge” and so therefore they believe that science is subjective and that subjectivity is based on the dominant factors of society in that time period.
By extension, postmodernists are also considered to be major skeptics because they come to question the truth of essentially anything that has any sign of being tainted by society. While they believe science is subjective, in an ideal postmodernist world everything would be completely objective and completely free of any social bias that may exist in our world today.
However, despite a postmodernist utopia being completely bias-free, postmodernists also believe that such a world is unattainable due to societal influences permeating everything down to our very definitions of words, and so even the way we perceive facts is with some bias.
Postmodernists seem like a pretty depressing bunch of people, don’t they?