The Readymade

The readymade or already-made work requires the viewer to regard the work in a way different to the way it is viewed outside of the gallery space. The context of the work, etc. But what legitimises the gallery as the authoritative context for the viewing of art? It is the previous, earlier art that it has already shown - the authority of its own history and of its function as a site of cultural display - a tautology of sorts.
The artist is, in effect saying "look at this in a way you would not outside the gallery".