a chicken and egg situation/problem etc
From Longman Dictionary of Contemporary Englisha chicken and egg situation/problem etca chicken and egg situation/problem etcEFFECT/INFLUENCEa situation in which it is impossible to decide which of two things happened first, or which action is the cause and which is the effect → chickenExamples from the Corpusa chicken and egg situation/problem etc• It's a chicken and egg situation really.