vicious circle

noun2

1. •
   A situation in which the response to one problem creates a chain of problems, each making it more difficult to solve the original one.
2. •
   A fallacy in which the premise is used to prove a conclusion which is then used to prove the premise.

   • But historical materialism cannot tell us why one is important and not the other, except on the ground that it is able to account for the latter-and this is clearly a vicious circle. — 1978