A "post-structuralist discourse" apparently "expands the agenda of social theory, posing questions that other discourses must refuse to ask" (Richard Ashley, Living on Borderlines). It 'opens up thinking space' (Jim George, International Relations and the Search for Thinking Space).
But poststructuralism itself is utterly incapable of asking a whole swathe of questions because of its own dogmatic ontological assumptions; its thinking space is suffocating. In fact, whatever ground it opens up is micrified by that which it forecloses; for example: the assumption that objects are reducible to the discursive conditions of their emergence eliminates the possibility of understanding what it even means to be 'critical.'
Take science (an excellent but not fundamentally privileged example):
Scientists are always engaged in criticism but they don’t criticise everything at once (‘perpetual critique’), nor could they, nor would they ever want to. This would disallow instrumentation or black boxing. No debate could ever end. Scientists don’t engage in perpetual critique because they believe that their subject matter is capable of objecting – of showing itself to differ from established knowledges.
This doesn’t mean that scientific objects can object on their own but many scientific discoveries have been made in the course of otherwise routine experiments that went awry, felix culpa; when one was looking for one thing but found another.
Simply: knowledge can become critical (i.e. unstable) without the instigating (which is not to say intentional, although it's similar) intervention of a (human) critic. Without the labour of scientists most scientific objects have no means of eliciting this surprise, it is true. But that doesn’t mean that making critical is dependent upon critique.
Making critical, in such cases, may only occur during scientific practice but that practice needn’t be critical per se; it is often or perhaps even usually routine, directed towards another end entirely.
And isn’t this how everyone saw the end of the Cold War? As an event that objected to IR theory itself? (Poststructuralists included.) Certainly it wasn’t self-interpreting but it demanded interpretation by social scientists (and everyone else for that matter). It is in no way reducible to interpretation or the sum of all human interpretations. If it was it could never demand interpretation.
(Does this mean that the demand transcends interpretation? I'd say not, it can be ignored, missed - nothing necessitates its being taken as a provocation and so its conditions of emergence remain pivotal but none of that makes its demand reducible to its interpretations. This is realism.)
Beware modesty dressed up as radicalism.
Beware radicalism generally when it runs from the typing fingers of middle-aged academics.
Poststructuralists are truly agoraphobic (and this is a nice little academic play on words). They are afraid of the outdoors, of things (at least in their work - in the rest of life they enjoy all the luxuries). Moreover, for all the talk of radical democracy and opening up debate they foreclose almost all of it by having such a limited and such a dogmatic ontology. They cannot ever genuinely stand in the agora and speak. They are doubly afraid of the outdoors and of things. Of things qua objects and things qua places of politics. They can barely stifle their grins and snorts when people talk passionately about their belief in the reality of things. This is my own ethnographic observation!
The 'thinking spaces' are not wide open spaces, they are closets.