Section — Vermeersch, Theologia Moralis
§ 1. What It Is, How Manifold It Is, What It Effects
I. What It Is. Prescription is an original mode, established by positive law, of acquiring a real right or of destroying an obligation or action, after a certain interval of time has elapsed, and with the other prescriptions of the law observed (Cf. art. 2105 Italian Code). - Positive law is canonical when ecclesiastical goods are in question; but, with certain points saved, this canonizes the civil laws of the various nations (c. 1508).
II. How manifold it is. Taken generically, it has two species: acquisitive prescription, which is more strictly called usucaption; and liberative prescription, which is more properly called prescription.
III. What it effects. 1. Acquisitive prescription (the usucaption of Roman law) at the same time confers an action for pursuing the thing, and an exception for repelling an adversary.
Liberative prescription confers an exception by which someone, at least if he wishes, can render the creditor's action entirely void. At least if he wishes, I say, because laws for the most part provide that unless it is opposed, the judge cannot attend to that means of forensic defense.
But observe that property or perfect ownership is not lost by mere liberative prescription or by non-use: one who does not use his own thing remains its owner at least in the external forum, until either the treasury assigns it to itself as vacant, or someone occupies it.
By acquisitive prescription, the law intends to give a means of obtaining a right which is inviolable at least in the external forum. But it can grant liberative prescription with a twofold intention: either of extinguishing the creditor's right itself, or merely of destroying his action. And certainly it does not intend to extinguish the right, if it permits the creditor to defer to the debtor an oath before the judge concerning the payment having been made, and if this is denied, the debtor is condemned to payment.
Each prescription acts backward, insofar as, after prescription has been completed, the one prescribing is considered to have been owner of the thing, or immune from the obligation, from the day on which he began to prescribe, so that from then on he owes neither fruits nor interest or usury.