Jameson submits two critiques of knowledge in the context of postmodernity. First, he claims that "[postmodern] theory seems necessarily imperfect or impure," since "no [self-coherent theories of the postmodern] have yet appeared"; indeed, this would require "an antifoundationalism that really eschews all foundations altogether, a nonessentialism without the last shred of an essence in it" (Introduction, xi-xii). In other words, slogans such as "no more meta-narratives" or "it's all about context" end up reinscribing the very metaphysical claims they set out to admonish.
Lyotard's belief of knowledge being an exchange of value is best shown with his description of the pragmatics of scientific knowledge. The overall goal of all science is to improve and strengthen the world, and scientific knowledge cannot be "knowledge in itself" because it requires other people to exist.
"Knowledge is and will be produced in order to be sold, it is and will be consumed in order to be valorized in a new production: in both cases, the goal is exchange. Knowledge ceases to be an end in itself, it loses its 'use-value'." (Lyotard 4-5) I believe the second half of this statement to be false and the first half to be inconsequential. As long as liberal arts colleges exist, knowledge will always be an end in itself. This class offers me no material gain, any knowledge I gain will broaden my understanding of the world, but will have little effect on my career in Real Estate.