Terry Pratchett knows. See his collaboration with Stephen Baxter The Long Earth.

"The 'Long Earth' is a (possibly infinite) series of parallel worlds that are similar to Earth, which can be reached by using an inexpensive device called a "Stepper". The "close" worlds are almost identical to 'our' Earth (referred to as "Datum Earth"), others differ in greater and greater details, but all share one similarity: on none are there, or have there ever been, Homo sapiens - although the same cannot be said for earlier hominid species, especially Homo habilis. The book explores the theme of how humanity might develop when freed from resource constraints: one example Pratchett has cited is that wars result from lack of land – what would happen if no shortage of land (or gold or oil or food) existed?"