Julián Montaño 
I was going to write about Works of Art, and indeed I am, but Miguel threw down a gauntlet that I want to take up (this antique gesture is matter for another post, indeed) I have change my mind and text (it’s the same thing, you see) and hope to kick off a Quaestio Disputata De Nomine Artificiis.
Are Works of Art a Natural Class? Is there is something in the world as the "Nature" of a Work of Art? Do Andy’s Warhol "Brillo Box" share some sort of "Nature" or "Essence" with, say, the baroque raredos of the Little Chapel of St Joseph in Seville, with Marguerite Yourcenar’s "Les dieux ne sont pas morts" or with Tomás Luis de Victoria’s "Officium Defunctorum 1605"? Scarcely. There is not such a thing as the "Essence" of a Work of Art, therefore there is not a common & shared "Nature" of a Work of Art. In fact there is no such a thing as "Works of Art" going all over the world ready to be discovered by you, as black swans were ready to be discovered by zoologists. What is it to be a "Work of Art" then? Nothing, it is just to carry the label of "Work of Art", a common label to describe, to group, certain objects, cultural constructs that we respect, take care of, like to have, etc. The impressive voice of "La Niña de los Peines" (a flamenco singer, one of the peaks of the evolution of this art) is a work of art, in fact her voice as such is catalogued as "Good of Cultural Interest" or some sort of naive label that cultural institutions like to apply to things -but, in any case, a voice, a tune of voice, is classified as work of art with the same nonchalance as sowing umbrellas all the way through a valley (a performance by Christo) is classified as a work of art.
Then if "Works of Art" are social artefacts, mere objects classified with certain (practical) label, how we identify then and differentiate then from NO-works of art? Is there is such a thing as a Catalogue of Works of Art? Yes there is. They are called Institutions: art galleys, museums, painters’ workshops, handbooks of History of Art, etc. Whatever could be included in and recognised by this net of Institutions is called "Work of Arts". In the same way as 100 pesetas notes are recognised as 100 pesetas notes by an Institution, the Bank of Spain. Whatever is not recognised by this Institution as 100 pesetas note (for instance a 100 pesetas note printed by me with my HP Injector printer) is not a 100 pesetas note.
This is the Institutional Theory of Art. Is now one of the most discussed theories of Theory of Art, and it has many challenges as one may suppose.
Other different question, but related is the following: Is there such a thing as "Natural Names"? Do certain things have a name by nature? For instance: the name of a friend of mine is Ataulfo (he is easily recognised when you shout his name in a crowd), does Ataulfo NECESSARILY have the name of Ataulfo? Is there such a thing as the nature of "Ataulfo" that lead his imaginative mother to name him "Ataulfo"? Well, it is not clear at all. I will advance that many times things NECESSARILY are called in the way they are called and you can not change the name without change the thing. This happens when things have "History" instead of "Nature"…
Names and the logic of names are very interesting. In fact the Conference I will give tomorrow at Instituto de Empresa is about -partly- Names and the scope & reach of Names.