validity of khabar wahid in main affairs (umur muhimmah)

Khabar wahid as one of the sources and proof of inference of rules of sharia has been subject of attention and faqihs have always been divided on whether or not it is valid proof as it was considered as valid proof by majority of faqihs in some period while it wasn’t in another. Today, the majority opinion is that khabar wahid is valid proof but no clarification has been made about applicability of khabar wahid as regards main affairs (umur muhimmah). Given the fact that there are many transmitters in transmission of khabar, which weakens the possibility of truth of khabar and considering rule spirit of sharia and common sense that caution must be when dealing with main affairs (umur muhimmah), this paper aimed to show that use of khabar wahid as the mere basis of making laws (such as stoning of adulterer and execution of apostates) in main affairs is contrary to spirit of sharia and common sense and therefore lacks support of reason and sharia.