Interdimensional hypothesis (Ufology)

The interdimensional hypothesis (IDH or IH), or extradimensional hypothesis (EDH), is a hypothesis in ufology that proposes UFOs constitute contacts with beings from other dimensions coexisting separate from but alongside our own, as compared to the extraterrestrial hypothesis (ETH) which suggests they are beings from other worlds. It can be considered as being a modern interpretation of Meade Layne's early Ether Ship theory of flying saucers, and has been advanced by such persons as John Keel, Jacques Vallée, and J. Allen Hynek.