Section — Wouters, Manual of Moral Theology
I. On Prescription Generally
I. Notion. Prescription is a mode of acquiring something, or of liberating oneself from some obligation, through a definite lapse of time and under conditions established by law.
II. Division. From the definition it is clear that prescription is twofold: acquisitive, by which someone acquires something; and liberative, by which someone is freed from an obligation. The former is also called usucapio.
III. Power of the civil State to establish prescription. The civil power, by force of eminent ownership, can for very grave reasons - in other words, when necessity or great common utility urges it - transfer rights and remove obligations (n. 764). But very grave reasons urge that, through a certain lapse of time, with certain conditions observed, in other words through prescription, rights be transferred and obligations removed. The reasons are: lest possessors be held in perpetual fear of losing their things; lest lawsuits always be able to be moved; lest debtors be compelled always to preserve receipts or testimonies of payment made; lest debts increase too much and thus create poverty for debtors (St. Alphonsus, III, 517). And this exercise of right is the more just because it does not diminish the rights of private persons. For before every event prescription favors one no more than another, since each has both fear of losing and hope of acquiring. It is, as it were, an aleatory contract which citizens can enter among themselves, and which the State imposes in the name of all. Moreover, even Canon Law generally, at least implicitly, approves prescriptions established by civil law, by the very fact that canon 1508 received "prescription, as a mode of acquiring and of liberating oneself, as it is in the civil legislation of the respective nation,... for ecclesiastical goods," with the prescription of the canons to be set forth afterward being saved.
Corollary I. Insofar as very grave reasons urge prescription upon the State, it is said to be introduced by the civil Authority, with natural law soliciting it.
Corollary II. Since prescription ultimately draws its force from positive law, it is clear that for the validity of prescription it is required that it be clothed with the conditions required by the aforesaid law.