Point I. On the Possessor in Good Faith

The possessor in good faith is bound as follows:

I. As regards the thing. 1. He who possesses another's thing¹ in itself is generally bound to return it as soon as possible to the owner, and indeed gratis. The thing, as the adage has it, cries out for its owner. I said generally; for one who bought a thing from another, for instance from a thief, can sufficiently probably return it even to the thief in order to recover the price, unless the owner, appearing, now claims his own thing for himself. The reason is that the buyer is not the cause but only the occasion of the damage that will follow for the owner; the cause of the damage is the bad will of the thief, while the buyer permits the damage. But avoiding the buyer's own damage, in this case recovering the price, is a just cause for permitting another's damage (St. Alphonsus, III, 569). If, however, the possessor can recover the price by another likewise easy way, he is bound to return the thing to the owner, since the cause for handing it over to the thief is lacking (St. Alphonsus, III, 569).

If the owner, appearing, claims his own thing for himself, the possessor can demand back from the seller the price paid by him. For the rest, let it also be seen what perhaps the law of the country establishes, for example concerning another's thing bought in public markets or in a public auction.

2. He who no longer possesses another's thing in itself, but in equivalent, is bound thus:

a) He who sold another's thing received gratuitously is bound to restore the price to the buyer, but the latter is bound to return the thing to the owner. But if the buyer refuses to return the thing, or it is foreseen that he will not return it, let the seller return the price to the owner of the thing insofar as it does not correspond to mere industry, and thus, insofar as can now be done, repair the equality violated also by himself, although without fault (St. Alphonsus, III, 609).

b) He who donated another's thing received gratuitously, and thus spared his own goods, is bound to warn the donee, who should restore the thing to the owner. But if he refuses to restore it, the donor is bound to restitution with respect to the owner; for he cannot become richer, to the owner's damage, from disposing of another's thing.

c) He who consumed another's thing received gratuitously, and thus spared his own goods, is likewise bound to restitution with respect to the owner, because, as was just said, he cannot become richer, to the owner's damage, from disposing of another's thing.

Both the donor, of whom under b), and the one who consumed another's thing, of whom under c), are bound to restore according to the value of his own thing preserved, if this is worth less than the other thing donated or consumed; but according to the value of the other thing donated or consumed, if his own thing preserved is worth more than the other thing donated or consumed. The reason for the former is that they are not bound to restore beyond what they spared of their own goods. The reason for the latter is that they are not bound to restore beyond the damage which the owner suffered.

d) He who sold at a profit another's thing which he had bought is bound per se to return the price to the buyer, while the latter must restore the thing to the owner (St. Alphonsus, III, 800). But if the buyer refuses to restore the thing to the owner, let the seller give to the owner the profit insofar as it does not correspond to industry (St. Alphonsus, III, 601; 609, 6; 825, compared with 609, 8 and 610). Of him who sold another's thing which he had bought without profit, there is no discussion here, because he has not been made richer from another's thing.

3. He who no longer possesses another's thing either in itself or in equivalent is not bound, as far as the thing is concerned, to restitution; for he is an inculpable damager (n. 995). The same must be said of him who doubts whether he in some way possesses another's thing (St. Alphonsus, III, 706).

¹ Note, a thing legitimately prescribed is no longer another's.

II. As regards the fruits of the thing, the possessor in good faith:

1. With attention paid to the law of nature, is bound to restore natural, civil, and mixed fruits, while nevertheless retaining the price of the labor furnished for producing them; he can retain merely industrial fruits. The reason is that the former arise from the thing itself, the latter from the labor of the possessor (St. Alphonsus, III, 607, 610).

2. As regards civil law, which commonly has force in conscience, see the Code of the country.

III. As regards expenses made, the possessor in good faith can deduct:

1. With attention paid to the law of nature: 1° necessary expenses, or those without which the thing would have perished or become worse; 2° useful expenses, or those by which the thing was improved; 3° voluptuary expenses, that is, those which serve only ornament or pleasure, insofar as the value of the thing has been increased by them; nevertheless the possessor can remove the ornaments, provided this is done without detriment to the thing; 4° expenses made for producing fruits which are not merely industrial,¹ or which he restores.²

2. As regards civil law, let the law of the country be consulted.

¹ Since he can retain merely industrial fruits, he himself must also bear the expenses.

² Of course he is not bound both to restore the fruits and besides to bear the expenses made.