Ilm-e-Ghaib (knowledge of the unseen) is that knowledge which is not acquired through the use of the visible senses or the intellect. The things that the physical senses can perceive or the light of intellect can perceive are not included in the definition of Ghaib. The second condition for a piece of knowledge to be termed Ilm-e-Ghaib is that the knowledge should be personal to the possessors, and should not be acquired through any source or medium. The third quality of Ilm-e-Ghaib is that it should not be finite or limited. It should have no beginning or end.
The knowledge which is not personal and is achieved through the medium of Wahi, Kashf, Ilham, or dream is not Ilm-e-Ghaib. Only those people can term it as Ilm-e-Ghaib who are buried in ignorance from head to toe and have never been touched by the winds of knowledge.
Maulana Allah Yar Khan (RA), Dalail-us-Sulook