We've been reading Shanks' and Tilley's Re-Constructing Archaeology for my Theories of the Past course, so I've been thinking a lot about constructivism. What I've realized is that, in order to truly move beyond Modernity, we have to have non-human agency - without it we will always fail. I've come up with three reasons for this - maybe there are more, so feel free to share if I've missed something, but here they are:
1) It's a matter of respect for the other entities that occupy our world - it's unfair to simply impose our interpretations upon those other entities. We can't do it to other people, so why should we do it to non-humans? This is actually fundamental, in a way, because Modern resource exploitation is predicated on the notion that non-humans do not have agency - that they are simply resources for us to manipulate to our will. To acknowledge non-human agency gets us away from this Modernist fallacy.
2) It gives us a solid ground to stand upon when making political or ethical claims. This is not the pre-existing, essentialist ground that positivists claim, but a (literally) constructed ground which we have to build by composing relations between various human and non-human agencies. Without non-human agency, we have no way of comparing different interpretations or constructions - all are equally false/true. Thus the interpretation of global warming skeptics is equal to the interpretations of climate scientists - there is no basis for distinction, and the only significant measure is how many people one can win over to their interpretation. With non-human agency, we can see how different interpretations or realities are constructed from relationships between human and non-human agencies, and make comparisons. These comparisons are based not on how "true" or "false" the interpretations/realities are, but, as Latour mentions, upon how well or poorly constructed they are.
3) It gives us a better idea of what needs to be done to effect change. What's needed is not simply to interpret a given pattern in a politically or ethically appropriate way, but to develop a context of relations which makes change possible. In other words, it's not enough simply to imagine the world the way we want it; we have to build the world we want to live in by constructing relationships between various agencies. This is likely going to take some time and effort, and we have to start from the materials we have on hand and deal with their idiosyncrasies.