I have struggled for a long time to understand what social constructivism is about and whether or not it poses a challange to the objectivity of science, passing from the dismissive rebuttals of Sokal & Bricmont to Putnam's delicate balancing on philosophical tightropes and the greatly enjoyable and deceptively crystal-clear looking essays of Rorty. What I found today is the sharpest attempt I have ever seen at defining what it means to say, for example, that "the solar system is a social construction". And even it slides into ambiguity at the end. So I am beginning to think that social constructivism is an idea that cannot be pin-pointed, that will forever tantalizingly elude us.
If you read the post I have linked to, you will notice (as a commentator there does at well) that while the first two points of the definition are clear, with the last one we get in trouble. Points 1 and 2 say that (1) there would be no concepts and "categorizations" in absense of human beings, something only a Platonist would deny, and (2) different conceptual descriptions of the same reality can be equally valid, if they are used for different purposes, something true as the practical utility of a geocentrical astronomical scheme for navigation shows. None of these claims, properly worded, should bring discomfort to a "scientific realist" that believes that the world described by science is "really there" and is not created by the description. As PTJ says, believing that the description creates the world is not social constructivism but idealism.
But in the third point we start seeing trouble, because it seems we must commit ourselves to say something realistic or something idealistic -and the resolution to avoid both begins to look a lot like fence-sitting. Quoting:
"3) Finally, social practices of meaning-making are complicit in the production of the objects that they purport to study. This is where a claim about social construction looks the most like an idealist claim, so I want to be very careful here: "the solar system is socially constructed" means that it is impossible to refer to the solar system except through the concept of 'the solar system.' We never approach the world as blank slates, and we never get unmediated access to "reality." As such, if we or other meaning-making creatures were to apprehend things differently, there would be no solar system, since 'solar system' only has meaning within a whole set of meaningful social practices."
There is a way to read the last sentence that is clearly idealistic (the solar system, Sun, planets and all, wouldn't exist without our meaning-making activities) but that is clearly not the reading intended. Another reading is that without the concept of "solar system" the solar system wouldn't be "the solar system" because nobody would have conceptualized the combination of Sun, planets, asteroids, etc. into one entity. But it is likely that this is not what is intended either, because any realist can accept that. And it is very difficult to determine a third possible meaning between these two extremes, the absurd and the commonplace.
There is one mistake the realist must avoid in this game (though I realize now that what I wrote above is very close to making it; it is a very tempting mistake!): saying something on the lines of "OK, without the concept of solar system the solar system wouldn't exist, but the planets and other stuff would." Because now the "social constructivist" (and we haven't yet understood what her position is exactly!) has the offensive; she can ask: "And what if we hadn't developed the concept of 'planet'?" The realist will retreat perhaps to atoms and their combinations being "really existent", but the SC can press on until the realist is left with nothing else than "Reality" or "Facts" or "The Thing-In-Itself" as the only mind-independent thing, with atoms, planets and galaxies being only mind-dependent, as they depend on socially created concepts. And now the SC plays her final card: "But isn't your "reality" or "thing in itslef" just another human concept, just like "planet" or "atom"? And even if it is not, why would you cling to something that is unexpressable and unknowable"? Checkmate!
To escape this disastrous dialectical trap (represented by Andreas in the comment thread) we must avoid at all costs conceding to SC that "the solar system wouldn't exist without our concept of it". We can and must agree that many different conceptualizations of the world are possible, and at the same time insist that once we have conceptualized in a certain way, the things we say with those concepts can be true. True, period; true about a mind-independent reality. Concepts are the tools used to think and talk and express truths about the world, and the truths expressed with them can be true unconditioned to anything social, except in the trivial sense that the concepts themselves are socially created.