Nouns

(n)regress, reasoning backwardthe reasoning involved when you assume the conclusion is true and reason backward to the evidence

Verbs

(v)regressgo back to a statistical means
(v)revert, return, retrovert, regress, turn backgo back to a previous state“We reverted to the old rules”
(v)regress, retrograde, retrogressget worse or fall back to a previous condition
(v)relapse, lapse, recidivate, regress, retrogress, fall backgo back to bad behavior“Those who recidivate are often minor criminals”