400. Today customs do not so often attain the force of law. Moreover, so difficult is it to know whether any custom has all the qualities necessary for establishing, modifying, or abrogating a law that only an expert is competent to judge in this matter.
401. Dispensation.—Human law has not the immutability of the Divine Law. Hence, not only may it be changed, but it may also be dispensed. Dispensation is a relaxation of the positive law made for a particular case by him who has the competent authority.
(a) It is a relaxation of the law—that is, it takes away the obligation of the law. Thus, it differs from permission, which is fulfillment of what is conditionally allowed by the law.
(b) Dispensation is made for a particular case—that is, it is granted when the provisions of the law, though beneficial to the community as a whole, are not suitable for a particular person or case. Thus, it differs, first, from abrogation and derogation, which remove the obligation of the whole or a part of the law for the entire community; and, secondly, from privilege, which is granted permanently as a private law.
(c) Dispensation is given by competent authority—that is, by the legislator or others who have the lawful power. Thus, it differs from _epieikeia_ and private interpretation, which are made by those who have no power to dispense.
(d) Dispensation is a relaxation of the positive law, for since the Natural Law is immutable (see 305), no dispensation can be given from its requirements. Thus, dispensation differs from the official declaration or interpretation of the Natural or Divine Law (see 315).
402. Those who have the power to dispense from a law are the lawgiver and others duly authorized. (a) The lawgiver himself can dispense as follows: in his own laws, since he was able to make them; in the laws of his predecessors, since his authority is equal to theirs; in the laws of his inferiors, since they are his subordinates. (b) Others can dispense who have received from the law, from their superior, or from custom the necessary authority to dispense.
403. Those Who May Be Dispensed from a Law.—(a) Since dispensation is an act of jurisdiction, only those can be dispensed who are in some way subject to the dispenser. Since, however, the jurisdiction used in dispensing does not impose an obligation but grants a favor, it is held that he who has the power to dispense others may also dispense himself, if his power is not restricted. (b) Since dispensation is an act of authority, it may be exercised even in favor of one who is absent, or ignorant of the dispensation or unwilling to accept it. But, since as a rule favors should not be forced, the validity of a dispensation generally depends upon the consent of the one dispensed.
404. The power of dispensing has for its end the common good, and therefore it must be exercised: (a) faith fully, that is, not for reasons of private interest or friendship; (b) prudently, that is with knowledge of the case and with judgment that there are sufficient reasons for dispensation.
405. In order that the reason for a dispensation be sufficient, it is not required that it be so grave as to constitute a physical or moral impossibility of keeping the law, since the obligation of the law ceases in the face of impossibility (see 317, 487), without the need of dispensation. Hence, lesser reasons suffice for dispensation.