「关键词」美国合同法重述，约因的充分性
§ 79. Adequacy Of Consideration； Mutuality Of Obligation
第79条。 约因的充分性；义务的均等性
If the requirement of consideration is met, there is no additional requirement of
在符合约因构成要件时，无需考虑下列额外要求：
（a） a gain, advantage, or benefit to the promisor or a loss, disadvantage, or detriment to the promisee； or
（a）（约因是否）给允诺人带来收益、优势或者利益；或者（约因是否）给相对人带来损失、劣势或者损害；或者
（b） equivalence in the values exchanged； or
（b）（双方当事人）所交换的价值（是否）相当；或者
（c） “mutuality of obligation.”
（c）（双方当事人的权利）义务（是否）均等。
Comment：
评论：
a. Rationale. In such typical bargains as the ordinary sale of goods each party gives up something of economic value, and the values exchanged are often roughly or exactly equivalent by standards independent of the particular bargain. Quite often promise is exchanged for promise, and the promised performances are sometimes divisible into matching parts. See § 31. Hence it has sometimes been said that consideration must consist of a “benefit to the promisor” or a “detriment to the promisee”； it has frequently been claimed that there was no consideration because the economic value given in exchange was much less than that of the promise or the promised performance； “mutuality of obligation” has been said to be essential to a contract. But experience has shown that these are not essential elements of a bargain or of an enforceable contract, and they are negated as requirements by the rules stated in §§ 71-78. This Section makes that negation explicit.
a.基本原理。在这样一个典型的普通货物买卖协商中，每一方当事人都放弃了一些经济价值，而且按照特定契约中的独立的标准，这些被交换的价值常常大致地或精确地相当。经常地，允诺换回另外的允诺，而允诺的履行在一些情况下则可分割为相匹配的几个部分。参见第31条。因此，约因有时会被认为必须由“允诺人的利益”或者“受允诺人的损害”构成；经常会有这样的主张：因为所交换的经济价值要远远少于允诺或者被允诺的履行中的经济价值，所以约因并不存在：“义务的均等”被认为对一个契约而言具有必要性。但是经验表明，在一个协商或者可执行的契约中，这些并非必备要素，而且第71-78条所规定的规则也否认它们是构成要件。本部分明确了这一否认。
b. Benefit and detriment. Historically, the common law action of debt was said to require a quid pro quo, and that requirement may have led to statements that consideration must be a benefit to the promisor. But contracts were enforced in the common-law action of assumpsit without any such requirement； in actions of assumpsit the emphasis was rather on the harm to the promisee, and detrimental reliance on a promise may still be the basis of contractual relief. See § 90. But reliance is not essential to the formation of a bargain, and remedies for breach have long been given in cases of exchange of promise for promise where neither party has begun to perform. Today when it is said that consideration must involve a detriment to the promisee, the supposed requirement is often qualified by a statement that a “legal detriment” is sufficient even though there is no economic detriment or other actual loss. It is more realistic to say simply that there is no requirement of detriment.
b.收益和损害。从历史来看，普通法上的债的行为被认为要求一个等价物，而且这一要求还可能导出这样的结论：约因必须是允诺人获益。但在缺乏这一要求的契约在普通法上的违约之诉中仍然得到执行；在违约之诉中，强调的是对受允诺人的损害，而且对允诺的有害依赖可能仍然是契约救济的基础。参见第90条。但是信赖对协商的成立并非必要性因素，而且在任何一方当事人均未开始履行的允诺交换允诺的案例中，早已规定了违约救济。现在，当有人认为约因必须包括一个对于受允诺人的损害时，其假设的要求经常由此表述得以满足：“一个”法律上的损害“即使在没有经济损害或者其他实际损失的情况下仍然是充分的。认为没有对于损害的要求的主张是更加现实的。
Illustrations：
例释：
1. A contracts to sell property to B. As a favor to B, who is C's friend, and in consideration of A's performance of the contract, C guarantees that B will pay the agreed price. A's performance is consideration for C's promise. See § 73.
1.A通过订立契约向B出卖财产。作为B的朋友，出于好意并考虑到A对契约的履行，C担保B将给付议定的价格。A的履行是C的允诺的约因。参见第73条。
2. A has executed a document in the form of a guaranty which imposes no obligation on A and has no value. B's surrender of the document to A, if bargained for, is consideration for a promise by A to pay $10,000. Compare § 74.
2.A以保证书的形式制作了一个未对自己施加任何义务也没有任何价值的文件。如果经过协商，B交出文件给A，就是A支付10，000美元的允诺的约因。比较第74条。
c. Exchange of unequal values. To the extent that the apportionment of productive energy and product in the economy are left to private action, the parties to transactions are free to fix their own valuations. The resolution of disputes often requires a determination of value in the more general sense of market value, and such values are commonly fixed as an approximation based on a multitude of private valuations. But in many situations there is no reliable external standard of value, or the general standard is inappropriate to the precise circumstances of the parties. Valuation is left to private action in part because the parties are thought to be better able than others to evaluate the circumstances of particular transactions. In any event, they are not ordinarily bound to follow the valuations of others.
Ordinarily, therefore, courts do not inquire into the adequacy of consideration. This is particularly so when one or both of the values exchanged are uncertain or difficult to measure. But it is also applied even when it is clear that the transaction is a mixture of bargain and gift. See Comment c to § 71. Gross inadequacy of consideration may be relevant to issues of capacity, fraud and the like, but the requirement of consideration is not a safeguard against imprudent and improvident contracts except in cases where it appears that there is no bargain in fact.
c.不等值的交换。就经济中的生产性能量和产品的分配被留给私人行为（private action）的意义而言，交易的当事人可以自由确定他们自己的估价。争议的解决经常需要一个更一般意义上的市场价值基础上的价值确定（a determination of value），而且这种价值经常被确定为多数私人估价基础之上的一个相似物。但在多数情况下，一个可信赖的价值的外在标准是不存在的，对于当事人的准确情形而言一般标准也是不适当的。估价被留给私人行为，原因之一是当事人被认为能够比他人更好地评价特定交易的情形。无论如何，他们通常是不能被限制而去遵从他人的估价的。
通常，法院因此而并不探究约因的充分性。在一方双方交换的价值不确定或者难以计算时尤为如此。但这即使在交易很明显是协商和赠与的混合的情况下也是适用的。参见第71条的评论c.约因的重大不充分可能与能力、诈欺和相似性问题相关，但是，除非在事实上没有协商的案例中，约因的要件并非针对轻率的、无远见的契约的安全保障措施。
Illustrations：
例释：
3. A borrows $300 from B to enable A to begin litigation to recover a gold mine through litigation, and promises to repay $10,000 when he recovers the mine. The loan is consideration for the promise.
3.A为了能够开始一项通过诉讼而重新获得金矿的诉讼而向B借了300美元，并允诺当他重新获得金矿时将偿还10,000美元。借款就是该允诺的约因。
4. A is pregnant with the illegitimate child of B, a wealthy man. A promises to give the child A's surname and B's given name, and B promises to provide for the support and education of the child and to set up a trust of securities to provide the child with a minimum net income of $100 per week until he reaches the age of 21. The naming of the child is consideration for B's promise.
4.A怀上了富人B的非婚生孩子。A允诺将给予这个孩子自己的和B的教名，B允诺将提供这个孩子的抚养和教育费用，并设立一个有价证券信托，以在这个孩子21岁之前每周为其提供至少100美元的净收益。对这个孩子的命名是B的允诺的约因。
d. Pretended exchange. Disparity in value, with or without other circumstances, sometimes indicates that the purported consideration was not in fact bargained for but was a mere formality or pretense. Such a sham or “nominal” consideration does not satisfy the requirement of § 71. Promises are enforced in such cases, if at all, either as promises binding without consideration under §§ 82-94 or as promises binding by virtue of their formal characteristics under § 6. See, for example, §§ 95-109 on contracts under seal.
d.虚假的交换。在有或没有其他情景的情况下，价值的不同有时意味着声称的约因在事实上并未经过协商，而只是一种单纯的形式或者伪装。这种虚假的或者“名义上的”约因不能满足第71条的要求。这样的允诺是能够执行的，如果它们是作为第82-94条下的无需约因的允诺或者是作为第6条下的依靠形式特征的允诺。参见，例如，第95-109条中关于铅封契约的规定。
Illustrations：
例释：
5. In consideration of one cent received, A promises to pay $600 in three yearly installments of $200 each. The one cent is merely nominal and is not consideration for A's promise.
5.考虑到接受的1美分，A允诺将以每次200美元的三年分期付款方式支付600美元。这1美分仅仅是名义上的而非A允诺的约因。
6. A dies leaving no assets and owing $4000 to the B bank. C, A's widow, promises to pay the debt, and B promises to make no claim against A's estate. Without some further showing, B's promise is a mere formality and is not consideration for C's promise.
6.A在临终时未留下任何遗产并且还欠B银行4,000美元。C作为A的遗孀允诺为A还债，B也允诺不对A的不动产提出请求。在没有进一步表示时，B的允诺仅仅是一种形式而非C的允诺的约因。
e. Effects of gross inadequacy. Although the requirement of consideration may be met despite a great difference in the values exchanged, gross inadequacy of consideration may be relevant in the application of other rules. Inadequacy “such as shocks the conscience” is often said to be a “badge of fraud,” justifying a denial of specific performance. See § 364（1）（c）。 Inadequacy may also help to justify rescission or cancellation on the ground of lack of capacity （see §§ 15, 16）, mistake, misrepresentation, duress or undue influence （see Chapters 6 and 7）。 Unequal bargains are also limited by the statutory law of usury, by regulation of the rates of public utilities and some other enterprises, and by special rules developed for the sale of an expectation of inheritance, for contractual penalties and forfeitures （see §§ 229, 356）, and for agreements between secured lender and borrower （see Restatement of Security § 55, Uniform Commercial Code § 9-501）。
e.重大不充分的效果。虽然在交换的价值存在巨大差异的情况下约因的要件可能得以满足，但是约因的重大不充分可能与其他规则的适用相关。“诸如撼动良知”的“不充分”经常被认为是“欺诈的徽章”，这就使得对契约义务的具体履行得以正当化。参见第364（1）（c）。不充分也可能有助于因能力欠缺（参见第15，16条）、错误、误述、胁迫或者不正当影响（参见第6章和第7章）而导致的无效或者撤销得以正当化。不平等的协商也受到暴利法的限制以及公共设施和其他企业费用的规制，以及为继承预期买卖、契约处罚和罚款（参见第229条，第356条）、有担保的出借人和借用人之间的协议（参见担保法重述第55条，统一商法典第9-501条）而发展的特殊规则的规制。
f. Mutuality. The word “mutuality,” though often used in connection with the law of Contracts, has no definite meaning. “Mutual assent” as one element of a bargain is the subject of Topic 2 of this Chapter. “Mutuality of remedy” is dealt with in Comment c to § 363. Clause （c） of this Section negates any supposed requirement of “mutuality of obligation.” Such a requirement has sometimes been asserted in the form, “Both parties must be bound or neither is bound.” That statement is obviously erroneous as applied to an exchange of promise for performance； it is equally inapplicable to contracts governed by §§ 82-94 and to contracts enforceable by virtue of their formal characteristics under § 6. Even in the ordinary case of the exchange of promise for promise, § 78 makes it clear that voidable and unenforceable promises may be consideration. The only requirement of “mutuality of obligation” even in cases of mutual promises is that stated in §§ 76-77.
f.相互性。“相互性”一词虽然经常在与契约法的联系中使用，却没有确定的含义。作为协商的要素之一，“相互同意”是本章第二话题的主题。在第363条的评注c中对“救济的相互性”有所涉及。本条（c）款否定了任何关于“义务相互性”的假定要求。这种要求有时以此种形式表述出来，“双方当事人必须都受到约束或者任何一方均不受到约束。”这一表述在适用于允诺交换履行时明显是错误的；它同样也不适用于由第82-94条所规制的契约和因具有第6条下的形式特征的优点而可执行的契约。即使在允诺交换允诺的通常情况下，第78条也清楚地表明：可撤销的和不可执行的允诺也可能成为约因。甚至在相互允诺的情况下，“义务相互性”的唯一要件是由第76-77条规定的。
郭剑寒
