Under the poststructuralist scheme, all meaning, truth or reality is only a social construction. There does not exist any universal objective foundation on which truth can be discovered. The modern view of the world of having structure and order on which we base our scientific research is only an alleged claim and in fact a political tool to oppress people and the nature. Since there is no objective foundation for knowing the truth, no truth can claim to be absolute. Some propositions can be true for you as long as they meet your political interest but they may not be true for me since I may have a different political interest from you.
All truth is relative, i.e. relativism.