Is it permissible to pray behind an imam who believes his shaykh knows what is on the minds of his murids?

The belief that other than Allah knows the unseen is disbelief that expels one from the faith and contradicts the clear Quran. Whoever believes that his shaykh knows the unseen has apostatized. However, a specific person is not to be declared a disbeliever until proof is established against them.

As for someone who does not believe that his shaykh knows the unseen, but rather believes that he possesses strong insight (firasah) through which he knows what goes on in the mind, this is not disbelief and does not expel one from the faith, and praying behind him is permissible.

Scholars have differentiated between a soothsayer (kahin) who reports on the unseen or what is in the conscience, and a person of insight (sahib al-firasah), as the latter is not a soothsayer.

If a person reports on something that has occurred on earth, then if he is not trustworthy in his religion, he should not be believed. If he is trustworthy and his information is not obtained through unlawful means, then he is not among the soothsayers.

Reporting on what is in the conscience is not considered disbelief unless one believes that the one reporting knows the unseen.