How has artist Joseph kosuth raised questions about the natures of his art in his Composition one and the three chairs?

I wasn't familiar with this piece until I looked it up. It is a chair, a life-size photo of that chair, and an enlarged dictionary definition of the Word "chair." If your gallery is displaying this work, you don't get the chair, the photo or the definition; you get a copy of the definition, a drawing explaining how to set it up, and instructions to get a chair, photograph it and blow the photo up to full size, create the poster with the definition on it (all of which is much easier now that we have big inkjet printers, than it was when Kosuth devised this piece) and hang it in a certain fashion.

Kosuth asks, is a concept valid if its realization changes every time it's executed?

My feeling of this piece is, it only displays its full power as a collection, perhaps in a book or a web page. If you see one installation of One and Three Chairs you think, "so what?" In isolation, this is a very boring work. Only when you see how a number of people have executed Kosuth's concept does this make sense.