an end in itself
Something that is its own entity with no greater purpose. My parents think that studying literature is an end in itself and will never lead to a career.
end in itself
A purpose or goal desired for its own sake (rather than to attain something else). For example, For me, writing books is an end in itself; they don't really make that much money. This expression employs the noun end in the sense of "final cause or purpose," a usage dating from the early 1500s.