OF CHANGE IN LAWS (FOUR ARTICLES)
We must now consider change in laws: under which head there are four points of inquiry:
(1) Whether human law is changeable?
(2) Whether it should be always changed, whenever anything better occurs?
(3) Whether it is abolished by custom, and whether custom obtains the force of law?
(4) Whether the application of human law should be changed by dispensation of those in authority?
Whether human law should be changed in any way?
Objection 1: It would seem that human law should not be changed in any way at all. Because human law is derived from the natural law, as stated above (Q[95], A[2]). But the natural law endures unchangeably. Therefore human law should also remain without any change.
Objection 2: Further, as the Philosopher says (Ethic. v, 5), a measure should be absolutely stable. But human law is the measure of human acts, as stated above (Q[90], AA[1],2). Therefore it should remain without change.
Objection 3: Further, it is of the essence of law to be just and right, as stated above (Q[95], A[2]). But that which is right once is right always. Therefore that which is law once, should be always law.
On the contrary, Augustine says (De Lib. Arb. i, 6): "A temporal law, however just, may be justly changed in course of time."
I answer that, As stated above (Q[91], A[3]), human law is a dictate of reason, whereby human acts are directed. Thus there may be two causes for the just change of human law: one on the part of reason; the other on the part of man whose acts are regulated by law. The cause on the part of reason is that it seems natural to human reason to advance gradually from the imperfect to the perfect. Hence, in speculative sciences, we see that the teaching of the early philosophers was imperfect, and that it was afterwards perfected by those who succeeded them. So also in practical matters: for those who first endeavored to discover something useful for the human community, not being able by themselves to take everything into consideration, set up certain institutions which were deficient in many ways; and these were changed by subsequent lawgivers who made institutions that might prove less frequently deficient in respect of the common weal.
On the part of man, whose acts are regulated by law, the law can be rightly changed on account of the changed condition of man, to whom different things are expedient according to the difference of his condition. An example is proposed by Augustine (De Lib. Arb. i, 6): "If the people have a sense of moderation and responsibility, and are most careful guardians of the common weal, it is right to enact a law allowing such a people to choose their own magistrates for the government of the commonwealth. But if, as time goes on, the same people become so corrupt as to sell their votes, and entrust the government to scoundrels and criminals; then the right of appointing their public officials is rightly forfeit to such a people, and the choice devolves to a few good men."
Reply to Objection 1: The natural law is a participation of the eternal law, as stated above (Q[91], A[2]), and therefore endures without change, owing to the unchangeableness and perfection of the Divine Reason, the Author of nature. But the reason of man is changeable and imperfect: wherefore his law is subject to change. Moreover the natural law contains certain universal precepts, which are everlasting: whereas human law contains certain particular precepts, according to various emergencies.
Reply to Objection 2: A measure should be as enduring as possible. But nothing can be absolutely unchangeable in things that are subject to change. And therefore human law cannot be altogether unchangeable.
Reply to Objection 3: In corporal things, right is predicated absolutely: and therefore, as far as itself is concerned, always remains right. But right is predicated of law with reference to the common weal, to which one and the same thing is not always adapted, as stated above: wherefore rectitude of this kind is subject to change.
Whether human law should always be changed, whenever something better occurs?
Objection 1: It would seem that human law should be changed, whenever something better occurs. Because human laws are devised by human reason, like other arts. But in the other arts, the tenets of former times give place to others, if something better occurs. Therefore the same should apply to human laws.
Objection 2: Further, by taking note of the past we can provide for the future. Now unless human laws had been changed when it was found possible to improve them, considerable inconvenience would have ensued; because the laws of old were crude in many points. Therefore it seems that laws should be changed, whenever anything better occurs to be enacted.
Objection 3: Further, human laws are enacted about single acts of man. But we cannot acquire perfect knowledge in singular matters, except by experience, which "requires time," as stated in Ethic. ii. Therefore it seems that as time goes on it is possible for something better to occur for legislation.
On the contrary, It is stated in the Decretals (Dist. xii, 5): "It is absurd, and a detestable shame, that we should suffer those traditions to be changed which we have received from the fathers of old."
I answer that, As stated above (A[1]), human law is rightly changed, in so far as such change is conducive to the common weal. But, to a certain extent, the mere change of law is of itself prejudicial to the common good: because custom avails much for the observance of laws, seeing that what is done contrary to general custom, even in slight matters, is looked upon as grave. Consequently, when a law is changed, the binding power of the law is diminished, in so far as custom is abolished. Wherefore human law should never be changed, unless, in some way or other, the common weal be compensated according to the extent of the harm done in this respect. Such compensation may arise either from some very great and every evident benefit conferred by the new enactment; or from the extreme urgency of the case, due to the fact that either the existing law is clearly unjust, or its observance extremely harmful. Wherefore the jurist says [*Pandect. Justin. lib. i, ff., tit. 4, De Constit. Princip.] that "in establishing new laws, there should be evidence of the benefit to be derived, before departing from a law which has long been considered just."
Reply to Objection 1: Rules of art derive their force from reason alone: and therefore whenever something better occurs, the rule followed hitherto should be changed. But "laws derive very great force from custom," as the Philosopher states (Polit. ii, 5): consequently they should not be quickly changed.
Reply to Objection 2: This argument proves that laws ought to be changed: not in view of any improvement, but for the sake of a great benefit or in a case of great urgency, as stated above. This answer applies also to the Third Objection.
Whether custom can obtain force of law?