The "correspondence principle" refers to the idea that new scientific theories must explain the phenomena that their predecessors could, and that in relevant domains they should converge on such predecessor theories as approximations. Another synonym for this principle could be the "consistency principle" as it demands that scientific theories remain consistent with one another, so that new theories do not contradict or invalidate previously established knowledge. Another synonym is the "continuity principle" since it suggests that newer theories must maintain continuity with the earlier ones in order to be considered valid. The principle of "coherence", or "comprehensiveness", is also often used to describe the correspondence principle as it requires new theories to account for all phenomena, not only the ones that fit the theory's predictions.