"Alternative hip hop, like all genres of art, is a social construction and as such the definition is open to debate."     

If with the term "social construction" in this sentance, the statement "Alternative hip hop, like all genres of art, is a social construction" is meant to convey that any musical work one calls "alternitive hip hop" happens to be the product of an agent operating under certain social conditions (as opposed to working in a vacuum), or if it is meant to establish that the term "alternative hip hop" was created by such an agent, then the statement is quite true.  However, a "social construction" typically is opposed to a "natural kind" in that it is only conventional.  In this sense it is not altogether clear if in fact the statement is true:  take the art genres "Oil Painting" and "Punk Rock":  it is not merely as a point of convention that we say these two genres are different, there is a matter of fact about it.  However, in neither of these senses does it straightforwardly follow that "as such the definition is open to debate."  I do not mean to contend that the definition isn't open to debate, but only that its openness to debate isn't tied in any direct way to whether it is a "social contruction".  In the first case, consider the terms "integer" and "one": both terms where surely created by agents in a social setting, yet their definitions are particularly rigorous.  As for the second case, i might say that a man is jewish just in case his mother were jewish. "Jew" in this sense is a social construction, it is purely social convention and not a natural kind in any ordinary way.  Nonetheless, we already stipulated a perfectly rigourous definition.            -J