a chicken-and-egg situation
a chicken and egg situation/problem
A situation in which it is unknown what happened, or what needs to happen, first. You need experience to get a job, but you need a job to get experience. It's a chicken and egg situation.
a ˌchicken-and-ˈegg situationa situation in which you do not know which of two connected events is the cause of the other: Is she unhappy because she gets into debt, or does she get into debt because she’s unhappy? I suppose it’s a chicken-and-egg situation.This comes from the question ‘Which came first — the chicken or the egg?’.
See also: situation