premise: Middle-earth is a setting.
hypothesis: Middle-earth is the fictional setting of much of British writer J. R. R. Tolkien 's legendarium . Tolkien 's most widely read works , The Hobbit and The Lord of the Rings , take place entirely in Middle-earth , and Middle-earth has also become a short-hand to refer to the legendarium or its fictional universe . Middle-earth is the north continent of Earth ( Arda ) in an imaginary period of the Earth 's past