The development of the modern error doctrine

(a) Usus modernus pandectarum

The sale of Stichus who was supposed to be Pamphilus, the problem of vinegar sold as wine, transactions concerning "golden" rings and "silver" tables, even the slave who is no longer a virgin but "iam mulier": the whole Roman repertory of cases was mulled over time and again by the authors of the ius commune.

⁰⁷ For details, see, for instance, Franz Wieacker, "Aufstieg, Blüte und Krisis der Kodifikationsidee", in: Festschrift für Gustav Boehmer (1954), pp. 34 sqq.; Pio Caroni, "Kodifikation", in: HRGII, col. 907 sqq.

“ § 12 Einleitung PrALR; § 2 ABGB.

¹⁵ Cf. e.g. Savigny, System vol. Ill, p. 336; Windscheid/Kipp, § 79 a.

¹⁰ South African law appears to have moved in a similar direction; cf. Van Warmelo, (1975) 38 THRHR 207 sqq. According to the Louisiana Civil Code, errors of law usually have the same effect on contracts as errors of fact and invalidate a contract "where such error is its only or principal cause" (art. 1846): Hoff, (1978-79) 53 Tulane LR 370 sqq.

^M Cf. e.g. Theo Mayer-Maly, "Rechtsirrtum und Rechtsunkenntnis als Probleme des Privatrechts", (1970) 170 Archiv Jur die tivilistische Praxis 133 sqq.

On this topic generally cf., for example, Theo Mayer-Maly, Rechtskenntnis und Gesetzesfiut (1969); idem, "Gesetzesflut und Gesetzesqualitat heute", in: Festschrift zum 125jdhrigen Bestehen der Juristischen Gesellschaft zu Berlin (1984"). pp. 423 sqq.; Josef Isensee. "Mehr Recht durch weniger Gesetze", 1985 Zeitschrift für Rechtspolitik 139 sqq.; Dieter Strempel (ed.), Mehr Recht durch weniger Gesetze (1987), passim

® For details cf. Peter Haupt, Die Entwicklung der Lehre vom Intim beim Rechtsgeschäft seit der Rezeption (1941), pp. 2 sqq.; cf. also the brief surveys by Coing, pp. 416 sqq., and Joubert, Contract, pp. 75 sq.

^m (T. e.g. Lauterbach, Collegium theoretico-practkum. Lib. XVIII, Tit. I, CV ("Error... voluntatem excludit, ac consensui est contrarius"); Voet, Commentarius ad Pandectas, Lib. XVIII, Tit. I, V ("Obest [consensui] error").

¹⁶ No need existed to draw a distinction between dissensus in the narrow sense (mutual mistake) and (unilateral) mistake. that it had to relate to the main content of the contract.^{[3150] 144 * [3151]} Thus, the parties must be ad idem as to each other's identity, as to the nature of their transaction and as to its subject matter (in the case of sale—still the standard example—object and price). Or, the other way round: consent is negatived by error in negotio, error in persona, error in corpore (plus error in substantia) and (where appropriate) error in pretio.^[3152] In these cases the rule of errantis voluntas nulla est was applied. An "error circa accessoria", on the other hand, was irrelevant. Likewise, a mistake about the quality, the value or the quantity of the object of the sale and (though this was very rarely expressly stated)^[3153] a mistake relating to the motive inducing a party to enter into the contract did not affect its validity.^[3154]

Certain features of the Roman doctrine of error were as vexing for the authors of the ius commune as they are for us.

(b) Error in persona

Only occasionally did one leave the well-trodden ground and introduce new ideas or distinctions. Thus, some writers argued that only the party in error should be permitted to invoke the invalidity of the transaction:¹⁵³ a rule that had been introduced in someone's favour should not be allowed to be turned to his disadvantage.¹⁵⁴ Probably the most interesting dispute related to the error in persona. Some 18th- century authors recognized that the principle of error excludit consensum had been taken much too far in this regard.¹⁵⁵ Very often in everyday life the parties to a contract are not at all concerned about exactly whom they are contracting with, and their interests do not then require the transaction to be null and void in case of error in persona. On the contrary: invalidity would be inconvenient and undesirable.¹⁵⁶ Hence the attempts to limit the range of operative errores in persona to those cases where the identity of the other party had been essential for the conclusion of the contract: consideration of the person must form "an ingredient in the agreement", and anybody invoking error in persona must be able to show "that he would have been unwilling to enter into a contract in the same terms with anybody else".

^IT>~ Cf. Bartolus, Cuiadus. Donellus, as quoted by Haupt, op. cit., note 120, pp. 22 sq. ^lj3 Cf. Haupt, op. cit., note 120, pp. 20 sq. (referring to Struve and Richelmann). '=* Mod. D. 1, 3, 25.

^1,3 Haupt, op. cit., note 120, pp. 23 sqq.

Cf, for instance, Treite!, Contract, p. 226, discussing the policy reasons why English courts have tried to restrict, as far as possible, the range of operative mistakes as to the identity of the other party.

1935 NPD 219 at 226.

^ljH Traite des obligations. § 19; but cf. e.g. Barbeyrac in his annotations to Pufendorf, Of the Law of Nature and Nations (tr. B. Kennett, 4th ed., London 1729), Book III, Chap. VI, 7. n. 2.

^13,9 For details on the reception of this Pothier rule in South Africa, cf. Reinhard Zimmermann, "Dor Einfluss Pothiers auf das romisch-hollandische Recht in Südafrika", (1985) 102 ZSS (GA) 172 sqq.

¹⁶⁰ Cf. e.g. J.C. Smith, J. A.C. Thomas, "Pothier and the Three Dots", (1957) 20 Modem Li? 38 sqq.; J.A.C. Thomas, "Error in persona and error in substantia", in: La formazione storica. vol. Ill, pp. 1203 sqq. and Latin texts from old civilian writers.^{[3157] [3158]} The principle enunciated by Pothier (for which there is no authority in Roman law) has been repeatedly criticized; to Thibaut^{[3159] [3160]} and Savigny¹⁶¹ (the great antagonists side by side!) it was irreconcilable with the will theory of contractual obligations, and so it still is for Professor De Wet of Stellenbosch.^[3161] English judges and writers, too, have occasionally expressed the wish to bury "this chief source of confusion" "once and for all".^[3162] Predominantly, however, the restriction of error in persona has been regarded as wholesome and practical, and thus it has prevailed not only in South Africa^[3163] and England,^[3164] but also on the European continent.'^[3165]

(c) The contribution of the natural lawyers

The natural lawyers, of course, tried to put the whole doctrine of error on a new, more rational basis.^{[3166] [3167] [3168] [3169] [3170] Thus, they rejected the Roman distinction between the various kinds of operative errors and quite a few of them not only redefined but also shifted the line dividing operative and inoperative errors not inconsiderably.}

"... si promissio fundata sit in pracsumtione quadam facti quod non ita se habeat, naturaliter nullam cjus esse vim: quia omnino promissor non consensit in promissum, nisi sub quadam conditione, quae reipsa non exstitit":¹⁷"

by way of a tacit condition, every motive that has induced a person to make a promise can therefore be read into his declaration. The whole construction is obviously based on a fiction,'⁷¹ and it remained but an ephemeral episode.

The most important and lasting contribution of the natural lawyers in this area of the law, however, resulted from their analysis of contract as being based on two (coinciding) declarationes voluntatis, each of which, in turn, consists of two components: signum volendi and volitio, or declaration and intention. ¹⁷~ Thus, it became possible to distinguish dissensus and (unilateral) error and to interpret error as a discrepancy or conflict between the two constituent elements of a declaratio voluntatis. Natural-law-inspired writers and legislators themselves, however, were not ad idem as to which of these two elements to emphasize. Some of them, placing the stress on commercial convenience and certainty, gave preference to the external manifesta­tion of the will. Both the Bavarian Codex Maximilianeus^{[3171] [3172] [3173] and the Austrian ABGB[3174] were guided by the (supposedly old German) principle of "error noceat erranti"[3175] and took account of any form of mistake by a party to a contract only under exceptional circumstances.[3176] Grotius and his followers, as we have seen, were much less strict in their approach; in fact, they even extended the scope of operative mistakes beyond what had traditionally been recognized by the authorities of the ius commune.}

with these kinds of objections.⁷⁷⁹ In the end, however, the fathers of the BGB went even further and resolved to grant a claim for the reliance interest, irrespective of whether the party in error had been at fault or not.^[3178]

(d) Error in Savigny's System and under the BGB

The most prominent voice against this new idea had, incidentally, been that of Savigny.^[3179] His exposition of the doctrine of error, as contained in volume three of the System, is usually regarded as a landmark par excellence for the interpretatio moderna of this topic;^[3180] Windscheid, for instance, did not hesitate to hail it as an "epoch-making" piece of legal writing.^[3181]

Savigny's importance in this area (as in many others) was not that of a great innovator. It lay in the manner in which he brought out and conceptualized the fundamental tenets underlying the sources of Roman law fas he understood them) and in which he tried to build up a coherent and logical doctrine on that basis. Thus, in this instance, his treatment provides the classic exposition of what has since become known as the "will theory".^[3182] Particularly important was the clear distinction that he drew between a mere error in motive (which does not affect the will of the contracting party but relates to the preliminary process of the formation of such a will) and an error in respect of the contents of the agreement. In the latter case there is no correspondence between will and declaration, and a declaration unsupported by a corresponding intention must be ineffective. More clearly than anybody else, Savigny spelt out the consequences of his basic premises: there can be no claim for damages, even if the party in error was at fault;^{[3183] [3184] every error in persona relates to the content of the declaration and must therefore be taken into account;1815 and every transaction affected by an operative error must be regarded as null and void, irrespective of whether the party who had been labouring under the mistake wished this to be the case or not.[3185] On all these points, Savigny took a stand against prevailing practice.}

Ultimately, however, it was not doctrinal accuracy that won the day. For even though the "will theory" gained broad acceptance,^{[3186] 8} pragmatic modifications thereto continued to be made, particularly in the three areas mentioned above. The BGB does grant a claim for damages,^[3187] takes into consideration whether the mistake induced the declaration^[3188] and leaves any decision about the validity of the contract to the discretion of the party in error.^[3189] Thus, the transaction is not invalid ipso iure, but may be rescinded by way of an informal declaration to the other party.^[3190] Apart from that, the BGB no longer refers to the old categories of error in negotio, corpore, persona or pretio; they had become obsolete in the course of the later 19th century.^[3191] Ironically, only the error in substantia, that chief source of doctrinal embarrassment, still shimmers through, albeit faintly. According to § 119 II BGB, a contract may be rescinded on the basis of an error as to those characteristics of a person or thing which are regarded in business as essential. It will be recognized immediately that this provision is much wider than the Roman notion of an error in substantia, particularly if the very liberal interpretation of the term "characteristics" by the German courts is kept in mind: it covers all legal or factual features of a thing that make up, contribute to or influence in the eyes of the general public its usefulness and value.^[3192] This includes, for instance, the age of a second-hand car and the existence of an expert opinion attesting to the genuineness of a work of art or the permissibility of building projects on a piece of property.^{[3193] [3194]} Rescission would also have been possible, according to German law, in that famous Dutch case^19ft where some old metal cup, dug up in the course of dredging works, had been sold without knowledge of the fact that it was actually a hcllenistic Kantharos of the 2nd century b.c. with Greek and Latin inscriptions (one of which concerned its owner, who may have been a Roman officer mentioned by Diodorus Siculus).

(e) Error in substantia

To most authors of the ius commune, such a wide-ranging recognition of a mistake, that related not really to the content of the contract, but rather to a quality of its object, would have been unthinkable. The somewhat exceptional category of error in substantia was usually taken to refer to cases where the material, in the sense of chemical substance, of the object of the contract had turned out to be different from the one contemplated by one or both of the contracting parties. Again, it was Savigny who pioneered a much more satisfactory approach. How odd that it should matter whether a sculpture by Benvenuto Cellini was plated with rather than made out of silver and not whether it was really attributable to that artist!^{[3195] [3196] Savigny therefore broadened the scope of error in substantia (a move for which, incidentally, he derived support from the error in sexu discussed in D. 18, 1, 11, I);198 for he recognized that a contract may be void, if the mistake relates to a substantial quality of the object. Substantial qualities, however, are only those which, according to notions prevailing in everyday life, cause a thing to belong to a specific class of objects.iyy Thus, on the one hand, he did not stick to the rigid, outdated and unsatisfactory criterion of "materia", but was (in this instance) prepared to accommodate a more pragmatic approach.200 Yet, on the other hand, he was keenly aware of the fact that recognition of every kind of mistake about (even essential) qualities was likely to undermine commercial certainty and be incompatible with the demands of business.201 Hence the requirement that the thing must have turned out to be an aliud, must have belonged to a different commercial category of objects.}

Savigny himself, incidentally, clearly recognized that error in substantia (however defined) was something of an anomaly in his doctrinal edifice; but respect for the sources of Roman law demanded not only its retention but also its rationalization as far as that was possible.²⁰² Even though Savi^ny's construction of error in substantia remained somewhat artificial/⁰³ it constituted an acceptable compro­mise solution and found its way into nearly all pandectist textbooks.²⁰⁴ Only towards the end of the century was some opposition voiced. Ernst Zitelmann declared that every error relating to a quality of the object constituted an error in motive and as such was irrelevant.²⁰⁵ The authors of the first draft of the BGB adopted this radical and rigidly dogmatic view.^[3197] But, as is so often the case, extreme views produce extreme reactions. The second commission wanted to be pragmatic, equitable and modern. Without much reflection,^[3198] it took a plunge into the dark and ventured to set out on what Leo Raape called a "mystery tour".^{[3199] [3200] [3201] [3202] [3203] [3204] [3205] [3206] [3207] It is widely recognized today that in this instance the legislator has failed in his task to find plausible and determinable criteria by which to separate relevant from irrelevant forms of error.204}

(f) Developments in French and English law

In other European countries there have been similar tendencies to extend the scope of operative error beyond the mere terms of an agreement to parts of what one could call the contractual environment.²¹⁰ We have seen how far Grotius was prepared to go—his doctrine of implied supposition opened the door for mere motives to be taken into account. ¹ Pufendorf modified and somewhat restricted this idea. He went back to the old distinction between essentialia and accidentalia negotii, but emphasized that the former also include "illae qualitates rei quas paciscens praecipue ob oculos habuit".²¹² Via Jean Barbeyrac (who translated and annotated Pufendorf 's main work), this formula gained entry into Pothier's influential Traite des obligations.²¹³ Pothier, of course, was not only the elegant stylist and a matchless popularize!” he was also a great amalgamator of legal ideas and various strands of tradition. Here we have an example, for it was Pothier who linked the view expressed by Pufendorf to the Roman error in substantia. "L'erreur annule la convention", he wrote,²¹⁴ "non settlement lorsqu 'elle tombe stir la chose ò¸òå, mats lorsqu 'elle tombe SHY la qualite de la chose que les contractans out eu principalement en vue, et quifait la substance de cette chose." And even though the French code civil refers only to the substance of the thing,²¹⁵ this clause is usually interpreted in the light of Pothier's statement on the matter.²¹⁶ Error in substantia has become a category subjectively determined, for it is taken to refer to the ^{[3208] [3209] [3210] [3211] [3212] [3213] [3214] qualities which the parties had principally had in mind. Again, the dangers of this approach for commercial certainty are obvious.[3215]}

Even English judges have occasionally succumbed to the strange and luring spell of error in substantia. The English law relating to error is particularly complex and confusing,^[3216] and if Continental doctrine has been referred to as perplexa satis,^[3217] the English one is certainly perplexissima.^[3218] It has grown together from separate roots (common law and equity) and is based on certain characteristic premises that make any comparison with continental systems difficult.^[3219] The very fact, as Professor Lawson says very pointedly, that systems derived from Roman law accept a certain solution "is a reason why English law should not".^[3220] And yet, one comes across a statement such as the following:

"And, as we apprehend, the principle of our law is the same as that of the civil law; and the difficulty in every case is to determine whether the mistake or misapprehension is as to the substance of the whole consideration, going, as it were, to the root of the matter, or only to some point, even though a material point, an error as to which does not affect the substance of the whole consideration."^{[3221] [3222] [3223] Blackburn J arrived at this conclusion after a lengthy review of Roman texts on error in substantia, and the whole passage has given rise to the inference that {common) mistake as to quality may under certain circumstances invalidate a contract in English law.2-4 On the other hand, however, it is clear that a unilateral error in substantia does not in any way affect the contract.225}

It need hardly be emphasized that the continental classification of error has in other respects, too, been regarded as useful at common law.^[3224] But, above all, the very idea that mistake can, under certain (albeit relatively narrow) circumstances, negative consensus,^[3225] has been received, via Domat, Pothier, Chitty, Colebrooke and the other treatise-writers from the civil law.^[3226] It has never fitted in very happily and has, in actual practice, been overlaid by estoppel ideas and the "objective test" approach.^[3227] But the fact remains that the English doctrine of mistake cannot be properly understood if one fails to realize that, essentially, it constituted a late importation into the common law, and one that was very closely related to the consensus doctrine of contract.^[3228]