§ 3. On Law Founded on Presumption.

169. Preliminary notions. 1. Presumption is a prudent judgment in an uncertain matter from circumstances frequently connected with the thing or fact.

It is called presumption because, before all other proofs, something is taken as true from the circumstances.

2. Presumption is divided: a. into presumption of man, which is formed by a prudent man, without being found expressed in law; and into presumption of law, which is expressed in the law.

If Gaius at night, in the presence of Titius his enemy, is found killed, Titius is presumed to have killed him. Laws presume anyone to be good until he is proved bad, and one who is once bad always to be bad in the same kind of delict.

b. Into presumption of universal danger, e.g. of fraud, sins, etc., and into presumption of a particular fact, e.g. of fault, fraud, negligence, etc.

3. A law or precept is said to be founded on a presumption of common danger when the law forbids or prescribes something in order to forestall a danger which is found to be frequently connected with some action or omission; and it is said to be founded on a presumption of fact (of sin), when a law or precept is established from a supposed fact which is held as certain, because it usually happens thus.

The law which prohibits the reading of bad books is founded on a presumption of danger; the law which prohibits mixed marriages; the law which prescribes the proclamations of marriages. The law which holds the father of an infant to be him whom the marriage indicates is founded on a presumption of fact; the law which holds one born of Christian parents and raised among Christians to have been baptized; the sentence of a judge condemning someone to paying a fine.

¹ Cf. Reuter, Theolog. moralis p. I. n. 155 ss.

170. The force of this law. A law which is founded on a presumption of fact does not oblige in conscience if the fact does not in reality subsist; but a law which is founded on a presumption of danger always obliges in conscience, even if in the particular case the danger were not present.

a. The reason for the first is that in this case, since the presumption is false, the foundation of the law or precept is lacking, and therefore also the obligation; hence the axiom: presumption yields to truth. Hence if someone is condemned by the sentence of a judge to pay a fine because of damage inflicted by his animal, he is not bound to pay it if the damage was not inflicted; and if he is compelled to pay, he can use occult compensation.

b. The reason for the second is that a law does not cease unless the end of the law has adequately ceased: for otherwise the evils which the law intends to forestall would not be efficaciously impeded, because many would falsely persuade themselves that no danger is present. Hence even he to whom no danger threatens from the reading must abstain from the reading of a prohibited book. Likewise one condemned by the sentence of a judge is bound to repair damage caused by his animal, even without his own moral fault, because the law intends not only to punish moral fault but also juridical fault, and thus to render men more cautious for forestalling damages.