Reservatio mentalis

(a) Roman law

The problem of a reservatio mentalis appears to have been of equally little practical importance in Roman law. To any practically minded lawyer it must be obvious that the secret (mental) reservation by one party to a contract not to be bound by his declared intention cannot affect the validity of the transaction.¹⁴⁴ Certainty of law and security of transactions would otherwise be undermined intolerably.

(b) Pandectists and canon lawyers

One has to attribute extraordinary significance to the intention of the parties in order to find this result anomalous or questionable. Such a shift of perspective can be based on a desire to "ethicize" legal relations, but it can also be the consequence of doctrinal rigidity. Nineteenth- ^{[3338] [3339] century legal science provides an example of the latter alternative. The result was not in dispute: a reservatio mentalis must be irrelevant.146 But how could this result be reconciled with the dominant will theory of contract? It is astonishing to see how this seemingly innocuous and rather impractical problem was able to acquire the awe-inspiring dimensions of a dogmatic "Cape Horn",147 the dreaded rock on which any attempt to explain the legal world of contract from a purely intention-oriented point of view appeared to be bound to founder. As a consequence, the problem of the reservatio mentalis featured particularly prominently among the arguments of the opponents of the will theory.14}

Many centuries earlier, canon law had even gone one important step further.

In the tradition of the Catholic Church, this decision was taken to attribute operative effect to a reservatio mentalis. Throughout the centuries, marriages were "dissolved" on this basis¹⁵¹ and, although the term "reservatio mentalis" is no longer used, contemporary Catholic marriage doctrine, as contained in the new Codex Juris Canonici, still places supreme importance on the "internus animi consensus" of the spouses. It is presumed to be in line with the "verbfa] vel signfa] in celebrando matrimonio adhibitfa]",¹⁵² but according to Can. 1101 II a marriage has not been validly contracted

Cf. e.g. Savigny. System, vol. Ill. p. 258.

^w Alfred Manigk. Das rechtswirksame Verhalten (19391. p. 142.

^ir On the role of the reservatio mentalis in the struggle between will theory and declaration theory cf. e.g. Otto Bahr. "Uber Irrungen im Contrahiren". (18751 \4JhJb 393 sqq. Josef Kohler. "Studien uber Mentalreservation und Simulation". (18781 \6JhJb9\ sqq.; idem. (18781 \6JhJb 325 sqq.; Bernhard Windscheid. "Wille und Willenserklärung". (18811 63 Archiu fur die civilistische Praxis 72 sqq.; Windscheid/Kipp.

For what follows cf. Heinz Holzhauer. "Dogmatik und Rechtsgeschichte der Mentalreservation", in: Festschrift für Rudolf Gtniir (19831. pp. 124 sqq.; idem "Reservatio mentalis", in: HRG, vol. IV. col. 926 sqq.

^m Decretales Gregorii IX, Lib. IV, Tit. I, Cap. XXVI.

^H "Quid absurdius dici fingique potuisset, non video", comments the Protestant Justus Henning Boehmer, Jus ecdesiasticum protest antium. Lib. IV, Tit. I, § 142.

¹⁵² Can. 1101 I Codex Juris Canonici (1983).

"si alterutra vel utraque pars positive voluntatis actu cxcludat matrimonium ipsum vel matrimonii essentiale aliquod elementum, vel csscntialem aliquam proprietatem".

The main difficulty, of course, lies in the proof of such a "positive act" of the will.¹⁵³ Lack of the (internal) intention to marry played a prominent role in the proceedings instituted by Henry VIII to get his marriage with Catherine of Aragon annulled,¹⁵⁴ and Napoleon Bonaparte (successfully) challenged the validity of his marriage to Josephine Beauharnais before the ecclesiastical courts on the basis of a reservatio mentalis.¹⁵⁵ Oaths, incidentally, were the other important legal act with regard to which the problem of a mental reservation became practically relevant.¹⁵⁶

4.