<Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (May 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (May 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> The melting pot is a monocultural metaphor for a heterogeneous society becoming more homogeneous, the different elements "melting together" into a harmonious whole with a common culture or vice versa, for a homogeneous society becoming more heterogeneous through the influx of foreign elements with different cultural background with a potential creation of disharmony with the previous culture . Historically, it is often used to describe the assimilation of immigrants to the United States . The melting - together metaphor was in use by the 1780s . The exact term "melting pot" came into general usage in the United States after it was used as a metaphor describing a fusion of nationalities, cultures and ethnicities in the 1908 play of the same name . </P> <P> The desirability of assimilation and the melting pot model has been reconsidered by proponents of multiculturalism, who have suggested alternative metaphors to describe the current American society, such as a mosaic, salad bowl, or kaleidoscope, in which different cultures mix, but remain distinct in some aspects . Others argue that cultural assimilation is important to the maintenance of national unity, and should be promoted . </P>

What process is the central idea behind americas melting pot