QUASI CONTRACT. - It is, according to doctrine and in certain positive legal systems (among them the Italian Civil Code of 1865), one of the sources of obligation (v.).
I. NOTION
For jurists, the quasi-contract is a voluntary and lawful act, from which an obligation toward a third party or a reciprocal obligation between the parties arises, without consent being joined to it, not even implicitly (cf. Italian Civil Code of 1865, arts. 1097, 1140). For moralists, on the other hand, with the exception of a few, a quasi-contract exists not only in the preceding case, but also in every case in which external consent is lacking but is tacitly included in an act (so-called tacit contract), as happens when someone assumes or accepts a post or office (for example, physician, judge, teacher, mayor, parish priest, etc.).
II. LAW
The doctrine of the quasi-contract is intimately connected with the historical origin of the name. Classical Roman law did not know this term, nor did it have a theory on the matter; it did, however, take into consideration certain transactions from which an obligation arose without the intervention of consent, and it likened these transactions to figures of contract. Having laid down as a principle that the essential element of a contract is consent, the post-classical jurists, being unable to fit these figures within it, elaborated the theory of the quasi-contract, designating by that name those lawful facts that gave rise to an obligation without the agent having the will or intention to contract it; and Justinian sanctioned the principle. These obligations non proprie nasci ex contractu intelliguntur, sed tamen quia non ex maleficio substantiam capiunt, quasi ex contractu nasci videntur (C. III, 28). The particle quasi in the text clearly indicates a resemblance and a distinction; there is the resemblance for the reason that in the cases mentioned a true obligation arises from a lawful fact (non ex maleficio); and there is the distinction insofar as there is no true contract without agreement or consent, at least tacit.
Among recent legislations, the German and the Swiss avoid giving a classification of the sources of obligations; the French and the Italian of 1865 (art. 1097) admit four sources of obligations. In doctrine the advisability of preserving the designation of quasi-contract was discussed, since it does not appear in the Italian Civil Code currently in force. Nevertheless, in the enumeration of the sources of obligations, it is affirmed that these derive from contract, from an unlawful act, or from any other act or fact suitable for producing obligations in conformity with the legal order (art. 1173). The legislator therefore, avoiding the term, admits other sources of obligation besides contract and unlawful act.
Among these acts or facts the current Italian Civil Code, following in the footsteps of the previous one, regulates three figures of quasi-contract: the management of affairs (arts. 2028-32), the payment of what is not due (arts. 2033-40) and unjust enrichment at another's expense (the Roman actio de in rem verso: arts. 2041-42).
It is disputed whether to these civil forms or figures of quasi-contract others may be added; in practice art. 1173 admits at least the possibility of other figures not specifically contemplated by the Code.
III. MORALITY
Moralists also include within the figure of the quasi-contract any obligation deriving from the acceptance or assumption of a public office and charge; in which case one should rather see a tacit contract. The reason for this extension may be found in the fact that, at the time when civil law became the object of moralists' attention, Roman law was not known and studied in its classical origins, but in the Justinianic redaction, with other modifications and non-Roman traditions, while the obligation deriving from a public charge could materially be likened to that of negotiorum gestio (quasi ex mandato). Recently some moralists have returned to the Roman concept; thus D'Annibale (Summula theol. mor., II, 4th ed., Rome 1896, n. 437) and Vermeersch (Theologiae mor. prim., II, ibid. 1923, n. 468); others simply point out the different notion, and others do not speak of it at all.
IV. ORIGIN OF THE OBLIGATION
Following the notion of Roman law, authors seek the foundation of the obligation of the quasi-contract in different theories; the one that finds greater favor and appears most consonant with juridical principles places the foundation in the principles of natural justice or equity, sanctioned by positive law, insofar as natural law forbids one who has received things not due to him or has managed the affairs of others to enrich himself to the detriment of third parties beyond the expenses incurred. For moralists, evidently, different foundations obtain, in harmony with the different concept of quasi-contract.
As a rule, the obligation arising from a quasi-contract is held to be one of strict justice, at least as regards the figures regulated by civil law, given the principle that the latter, in matters of determining the right of property, by sanctioning or completing natural law, binds in conscience. One must therefore abide by the relevant norms given by civil laws under pain of sin, unless in the specific case the application proves contrary to the principles of natural justice. This rule holds also in ecclesiastical matters and for ecclesiastical persons among themselves, by virtue of and within the limits of can. 1529. To be sure, the canon speaks expressly only of contracts, both in general and in particular, both nominate and innominate; but according to can. 18, quasi-contracts must also be included, also because the CIC does nothing but refer to civil law as regards obligations, concerning itself only with what is properly ecclesiastical matter.
If one considers in particular the various positive prescriptions (for example, of the current Italian Civil Code), one must note that the obligations arising from quasi-contracts stand out clearly from those derived from contract; and whereas in the latter the will of the individual manifested in consent fixes their terms in harmony with or in addition to the law, the obligations of a quasi-contract follow norms of natural equity, interpreted either by the law or by the judge (arts. 2030, 2031, 2037, 2038).
As regards the moral aspect of quasi-contracts in the moralists' acceptation, the general norms hold concerning sufficient expertise and adequate up-to-dateness, concerning diligence in the discharge of one's office such as the good pater familias employs, a diligence that translates into readiness to respond to requests, into loyalty and commitment in promptly bringing the matter to a good conclusion, into the exclusion of every form of corruption or of favoritism, without forgetting the grave duty of charity to lend one's services gratuitously in the cases prescribed by law or required by the poverty of the individual.