Sec 177

A consent of two minds to one and the same thing being an essential incident of contracts,1 it follows that there can be no contract when the parties differ essentially as to the thing they have in view. A distinction is made by the old writers in this respect between error and ignorance. Error consists in a judgment which, resting on incorrect information, is a perversion of the truth, while ignorance is a total want of information as to the particular topic; but ignorance has the same legal effect as error, and may be, therefore, classed under the same head. Error is also, so far as regards the subject matter, divided into error of fact, which, when material, avoids, and error of law which usually does not have that effect.2 So far as concerns the parties, error is unilateral, when it affects only one party, and bilateral, when it affects both.3 With regard to the possibility of avoidance, it may be either vincible (vincibilis), or invincible (invincibilis), under which head are classed, not errors which are absolutely unavoidable, for there are none such, but errors which could not be avoided unless by researches unusual with prudent men under similar circumstances.4 Error, also, viewed in relation to the effect it has on the will, is regarded as either essential (error essentialis s. causam dans) when it touches the substance of the negotiation, or unessential (concomitans) when it touches only collateral incidents, or matters of opinion.5 That there is no contract when there is an essential error by one of the parties is argued by Savigny to be a settled doctrine of the Roman law. "In omnibus negotiis contrahendis, is error aliquis intervenit, ut aliud sentiat-nihil valet, quod acti sit."6-Savigny's position, that where there is an essential error In Roman law unconscious essential error precludes contract.

1 See supra, sec 4. 2 See sec 193 et seq.

3 As to rectification see infra, sec 205, 602.

4 As to liability for negligence see infra, sec 1043.

5 See infra, sec 188.

6 L. 57, D. de oblig. et act. (44. 7).

The following passages are cited by Savigny as bearing on the question in the text: "Cum non consentiant qui errent. Quid enim tam contrarium con-sensui est quam error qui imperitiam detegit?" L. 15, de juris. (2,1).- "Error enim litigatorum non habet con-sunsum." L. 2, pr. de jud. (5, 1).by a party, there is no actual consent,1 is spoken of by Wind-scheid,2 as "epoch-making" in the doctrine of error; and he is sustained in this by the great body of German jurists.3 Windscheid, who occupies (1882) the highest rank as a commentator on the Roman law, adopts substantially the same position.4 Error, according to his definition, is where a party has no consciousness that he does not really intend that which he professes to intend. "He believes either that what he says has a different meaning from what it really has or that he uses different language from what he really does." The promise of a party made under such an error, it is sometimes said, is a nullity on account of the error. According to Windschied, however, this is not accurate. The nullity i. et ii. de errore in contractibus ; Gundling, uber die schwere Lehre von dem Irrthum in der Rechts gelerhr-theit; Leyser, de ignorantia et errore ; Hankopf, de effectu erroris in contractu emti venditi; Goetz, de errore in transact. etc. ; Van Maanen, de ignorantia et erroris natura et effectibus ; Kern, de errore contrahentium; Herr-man, von den Wirkungen des Irr-thums ; Kritz, de erroris facti; Thibaut, tiber die Wirkung des Irrthums ; Va-lett, Versuche eine von der gewohn-lichen abweichende und einfachere Theorie von dem Einflusse des error und der ignorantia facti auf die Rechts geschafte aus dem Rom. Rechte und aus der Natur der Sache abzuleiten; Muhlenbruch, uber Juris et facti ignorantia ; Richelmann, commentatio de facti errore in conventionibus. In addition, the topic is discussed at large in the works of Cujacius, Donellus, Ave ranius, and Gluck.

"Nulla enim voluntas errantis est." L. 20, de aqua pluv. (39, 3).-" Non videntur, qui errant, consentire." L. 116, sec 2 de R. J. (50, 17).-" Cum errantis voluntas nulla sit." L. 8, c. h. t.-But that these maxims are not to be held to imply that any kind of error prevents any kind of consent to a contract, is shown not only by the context, but by the whole doctrine or dolus wrought out with such care and completeness by the Roman jurists. There would be no necessity in any case to prove dolus (fraud) in order to rescind a contract, since, if there were any error, no matter how slight, there would be no contract to rescind. But in the Roman law, as well as in our own, fraud is held in many cases as of decisive influence in vacating a contract which would otherwise be held good. The party injured can in such cases hold to the contract and sue for damages, or may rescind the contract; and it is plain, therefore, that error does not as a rule preclude that consent by which contracts must be made.- Error in contracts has been the subject of copious discussion by foreign jurists. The following treatises on error are noticed by Koch: II. 129. Feltz, diss.

1 System Rom. Rechts, iii. 135-9.

2 Pandekt. sec 76.

3 Wachter, ii. sec 102; Vangerow, iii. sec 604; Sintenis, i. p. 193; ii. 298; Unger, ii. 89.

4 Pandekt. 3d ed. sec 76.

of the promise does not arise from the error, but from the fact that the promise and the intention do not correspond.-The great merit of Savigny, according to Windscheid, is that he brought into prominence the distinction between error in which the intention and the expression coincide, and error in which they are at variance. Inthe latter case the transaction (supposing the error to be essential) is vitiated not because of the error, but because of the variance. If there was another intention, as is usually the case in such errors, such intention cannot be the basis of an obligation; since intention without words is as inoperative as words without intention. From this follows the important position that nullity is not excluded in cases where the error was negligent, though in such cases negligence may estop.1 According to Windscheid, however, it is not sufficient to avoid a promise that it was made under an error; it is necessary that the thing promised either in its entirety (as where a party signs a wrong document), or in one of its essential constituents, was not intended. As essential constituents Windscheid enumerates:-