It's always interesting asking Post-Modernists who state that "western science" is just a belief system like any other and no more absolutely valid than any other world-view,

I've never encountered a postmodern resistance to science such as you suggest. I see and use pm as a way to explain why we don't all really read the same book even if we all pick up the same text and read it. Postmodern interpretation understands that when you read the word "tree" and I read the word "tree" we each have our own set of trees that we deal with an visualize something known to us. It was a response to formalist/formalism as a teacher-led "this is what the book means, period" and disregards what the reader brings to the text.

Perhaps it is because of my background in English and Philosophy that the the postmodern readings I used simply privilege the reader as bringing something to the text. It doesn't however dismiss the text, or in your usage, it doesn't dismiss science. I think it is laying too much on the term "postmodern" to suggest that people who don't accept science because they bring their own fallacies to the topic are using a postmodern approach. I considered myself a postmodernist all through my graduate studies, and I know it is imperative that people take science seriously and treat it as credible.

Postmodern thinking is a point of view that tends to move a certain privileged class from the center. Derrida mentioned "writing back to the center" as a way to indicate that others have equally valid understandings in the context of literature and intellectual discourse. That doesn't mean the lunatic fringe may dismiss science and portray said dismissal as purely semiotics in action. Willful stupidity by offering faulty reasoning and logical fallacies is not a function of postmodernism, even if flat-earth thinkers may attempt to characterize their knuckle-dragging ideas in such a way.

SRS