With generalization of the liberty-depriving prison sentence, diverse philosophies arise to justify the right of the State to impose it. Thus, corrective theories appear with their variants of improvement, the one related to danger and more contemporaneously, what is called by some authors the philosophy of “re,” imbued with diffuse concepts such as “social reinsertion, re-education, social re-adaptation, re-socialization,” among so many others, which go back to the idea of functionalism. All of these are directed towards legitimating the intervention of the State in applying the privation of liberty and shaping the life of the detainees. Re-approaching reflection on these theories means insisting on a situation that still has no answer. Such is the question: How and under what presuppositions can the privation of liberty on the part of the State be justified? As can be seen, this deals with reflecting on the permittive pretension in a State of Social and Democratic Right, that is, a topic of practical actuality in the area of Penal Law in force in current criminological analysis.