减少损失（Mitigation）
1 序言
受害方向违约方或侵权方索赔损失时，被告常常会争辩道“即使我违约（或侵权），可是我违约本来也不会造成这么大后果啊!是你没有采取合理措施减少损失，才会有这么多的损失，我只能赔你这部分，其他一概不赔!”的确，除了“损失的遥远性”（remoteness）与“因果关系”(causation)的局限外，还有受害方减少损失的责任，而且，这三个局限赔偿的大原则都是有相互的密切关系的。在减少损失的大原则下，每个受害方都应该合理地去减少自己的损失，如果没有合理减少损失的话，他就不能把自己应能减少而没有去减少的那部分损失向违约方索赔回来。这一大原则是有几个方面的大道理去支持的，如下：（一）与因果关系有一定的关系，就是违约方/侵权方虽然有赔偿责任，但受害方没有合理减少损失而造成的部分额外损失与原来的违约或侵权没有直接的因果关系。（二）与损失的遥远性也有一定关系，就是违约方/侵权方是没有料想到受害方是不会合理减少损失的，所以额外的损失在本质上是太遥远。（三）要求受害方去合理减少损失是为了避免整体的经济损失与浪费。（四）这涉及了公平对待双方当事人，就是受害人如果想多花钱，他可以自己掏荷包，没有理由要违约方/侵权方去承担他的奢侈行为。这方面可去节录Pearson大法官在Darbishire v. Warran（1963）1 WLR 1067所说如下：“he is fully entitled to be as extravagant as he please but not at the expense of the defendant.”
针对减少损失的大原则，最权威的说法是在British Westinghouse Electric & Manufacturing Co Ltd v. Underground Electric Rys. Co of London Ltd (1912) AC 673先例中，贵族院的Viscount Haldane说：
“The fundamental basis (of damage assessment) is thus compensation for pecuniary loss naturally flowing from the breach; but this first principle is qualified by a second, which imposes on a plaintiff the duty of taking all reasonable steps to mitigate the loss of consequent on the breach, and debars him from claiming any part of damage which is due to his neglect to take such steps.”(在计算损失，最基本的道理是去以金钱赔偿来自违约的损失，但这是第一个大道理，要受到第二个大道理的约束，就是强加在原告受害方的头上一个责任
去采取所有的合理行动减少因为违约所带来的合理损失，并禁止他去索赔任何部分由于其疏忽没有采取这些行动而造成的损失。)
要求受害方去合理减少损失的道理也很简单，可去以一个简单例子说明。比如买方因为市场价格下跌或己方原因拒绝收货，卖方应当合理尽速地在市场上把货售转售出去以取回一定货价。而不应任由该票货物闲置而导致最后霉坏不值一文，甚至还有一大笔的仓储费用与弃置处理费用，而这种情况在现实中会出现，特别是在受害方意气用事，明显不可行但仍坚持买方让步的情况下。这很容易客观看到如果要求买方（即使毁约的责任是100%的明确）赔偿全部货价并加上各种费用，是非常不公平的。这里当然会
涉及了每一个案件不同的事实，例如同样造成这一个严重的结果是由于卖方没有办法去合理到替代的买家，例如是该票货物比较特殊，根本没有其他人要，或当时遇上金融海啸根本没有市场或替代买方。这一来，要求买方承担所有的损失就客观看是理所当然了，因为卖方有设法去合理减少损失，只是没有成果罢了。又例如该票货物（例如是一台特殊制造的机器）根本没有市场或不到替代买方，也不代表卖方没有合理去减少损失的做法。例如去尽快安排把货物转运回自己的工厂，或是以废铁价格处理掉，或是以大幅度减价去出售给原来的买方（但不放弃卖方将来索赔的权利：Payzu Ltd v. Saunders [1919] 2 KB 581; A.B.D. [Metals & Waste] Ltd v. Anglo Chemical & Ore Company Ltd [1955]) 2 Lloyd‘s Rep 456），等等。反正就是能够合理去减少损失，即使成效不会太大，受害方还是应该这样做。在《1979年英国货物销售法》之50 (3)是针对买方对卖方的毁约，也就是本段所介绍的情况，就说明表面的损失计算就是根据合约价格与市场价格的差别，只要是在违约当时有一个可供买卖的市场，如下：
―50(3) Where there is an available market for the goods in question the measure of damage is prima facie to be ascertained by the difference between the contract price and the market or current price at the time or times when the goods ought to have been accepted or (if no time was fixed for acceptance) at the time of the refusal to accept.（如果有关货物是有一个可供买卖的市场，表面的损失证据是去根据合约价格与买方拒绝接受货物当天的市场价格。）
背后的大道理就是要求受害方应该尽快去合理减少损失，而只要有一个可供买卖的市场，去在该市场把
货物处理掉是最合理的做法。同时，通过这样的处理，也可以去
出受害方实际的损失，也就是出毁约的买方应该负责赔偿的金额，因为通过市场出售给替代买方而取得的价格是最好的指标去出与合约价格的差价。正如The ―Clyde‖(1856) Swab 23先例中，Dr. Lushington大法官是这样说：“It is the market price which the Court looks to, and nothing else, as the value of the property. It is an old saying, ‗The worth of a thing is the price it will bring‘.”
在进一步探讨减少损失的大原则之前，不妨先去简单介绍一下British Westinghouse Electric & Manufacturing Co Ltd v. Underground Electric Rys. Co of London Ltd (1912) AC 673与Darbishire v. W arran（1963）1 WLR 1067的案情。在British Westinghouse先例，涉及了一座蒸汽机的出售，用在火车的车头。由于该蒸汽机不符合买卖合约的要求，本身在动力与经济的操作上有缺陷，这导致了受害方买方在使用了一段时间后购买另一台蒸汽机作为替代。该替代的蒸汽机是一个不同的型号，有更大的动力，导致了在操作上所带来的利润比原来一台蒸汽机即使在符合合约规定的情况下也更高。在后来的诉讼中，受害方作为原告索赔替代蒸汽机的价格以及其他有关的损失。但并不成功，因为判是替代蒸汽机所带来的更高利润是足够对冲买方的损失的。
在Darbishire v. Warran先例中，涉及了原告把被告损坏的一辆车子去进行修理，但修理是不符合经济的做法的。上诉庭判是被告只需要负责赔偿损坏车子所带来的市场价格的减损（diminution in market value），而不是高昂的修理费用。
2 减少损失的三个规则
损害赔偿中，受害方减少损失的“责任”实际上包括三个规则：第一，如果受害方可以采取合理行动减少损失而没有采取，则对其所受损害的赔偿只限于若他采取了合理行动仍然会承受的那部分的损失；第二，一方违约/毁约后，如果受害方采取的行动事实上避免或减少了的损失部分，那么损失赔偿亦要相应免除或扣减。既使受害方所作所为已超出了合理减少损失所要求的范围，他也不应去赚一笔；第三，受害方为减少损失采取合理行动而作出的花费，成功与否，可以得到赔偿。
这方面可以去节录《Chitty on Contract》（2008，30th ed）之26-101段：
“Mitigation. There are three rules often referred to under the comprehensive heading
defendant
of ‗mitigation‘: they will be considered in turn. First, the claimant cannot recover damages for any part of his loss consequent upon the defendant‘s breach of contract which the claimant could have avoided by taking reasonable steps. Secondly, if the claimant in fact avoids or mitigates his loss consequent upon the defendant‘s breach, he cannot recover for such avoided loss, even though the steps he took were more than could be reasonably required of him under the first rule. Thirdly, where the claimant incurs loss or expense in the course of taking reasonable steps to mitigate the loss resulting from the defendant‘s breach, the claimant may recover this further loss or expense from the defendant.”
这三条规则在著名先例British Westinghouse Electric & Manufacturing Co Ltd v. Underground Electric Rys. Co of London Ltd (1912) AC 673中有针对，第一条规则是这样说：“…imposes on a plaintiff the duty of taking all reasonable steps to mitigate the loss consequent on the breach, and debars him from claiming any party of the damage which is due to his neglect to take such steps.”而第二条规则是这样说：“When in the course of his business [the claimant] has taken action arising out of the transaction, which action has diminished his loss, the effect in actual diminution of the loss he has suffered may be taken into account even though there was no duty on him to act.”至于第三条规则，基本上就是第一条规则的衍生。
3 减少损失是否受害方承担的责任？
Viscount Haldane在著名先例British Westinghouse Electric & Manufacturing Co Ltd v. Underground Electric Rys. Co of London Ltd (1912) AC 673中，把减少损失称为是受害方的一种“责任”（duty of taking all reasonable steps to mitigate the loss of consequent on the breach），这一说法就带来了一些争议。这是因为受害方如果有这一默示责任，就表示他没有去合理减少损失，就变了是违约并导致违约方/侵权方可以倒过来向他索赔。但实际上没有减少损失的后果只是不让受害方去索赔由于他没有合理减损而造成的这部分额外的损失。所以后来有不少先例对这一“责任”是有所澄清，说明并不是这样一回事。首先，可去节录Pearson大法官在Darbishire v. Warran（1963）1 WLR 1067中所说：
“For the purposes of the present case it is important to appreciate the true nature of the
so-called ‗duty to mitigate the loss‘or ‗duty to minimise the damage‘. The plaintiff is not under any actual obligation to adopt the cheaper method: if he wishes to adopt the more expensive against the defendant or anyone else. The true meaning is that the plaintiff is not entitled to charge the defendant by way of damages with any greater sum than that which he reasonably needs to expend for the purpose of making good the loss.”
另在The“Solholt”（1983）1 Lloyd‘s Rep. 605先例的一审中，Staughton大法官是这样说：“In this context it is perhaps worth repeating that the duty to mitigate is not in any sense an obligation, contractual or otherwise. It is a condition attached to the right to claim damages: see Mr Justice Robert Goff in Koch Marine Inc. v. D‘Amico Societa Di Navigazione ARL (1980) 1 Lloyd‘ s Rep. 75”。另在上诉庭，Donaldson大法官也有同样的说法：“A plaintiff is under no duty to mitigate his loss, despite the habitual use by the lawyers of the phrase ‗duty to mitigate‘. He is completely free to act as he judges to be in his best interests. On the other hand, a defendant is not liable for all loss suffered by the plaintiff in consequence of his so acting. A defendant is only liable for such part of the plaintiff‘s loss as is properly caused by the defendant‘s breach of duty.”
4 减少损失大原则与其他计算损失大原则之间的关系
较早时候已经提过，减少损失大原则与其他计算损失的大原则，包括损失的遥远性，损失的因果关系，甚至是整体减少浪费，都有一点关系。但它们实际上还是不同的大原则或者说法，虽然它们经常会混淆在一起，例如在针对受害方穷困而无法减少损失的情况下，就往往与损失的遥远性分不开，这稍后在第9段会解释。针对损失的遥远性，是不去理会受害方到底合理或者不合理，只要损失类别是订约的时候双方料想不到的，就会属于遥远的损失类别。但减少损失就非常讲究受害方的合理性。它们之间的不同可以举两个先例作为介绍，第一个是The ―Borag‖ (1981) 1 WLR 274先例。案情涉及了被告错误扣押原告的船舶，逼使原告提供银行担保去放船。但由于原告的银行资信很差，导致了要去支付给银行全部担保金额的利息，Denning勋爵说从来没有听说过银行有这么严格的做法。在上诉庭判是这一损失属于太遥远的损失类别，与受害方是否减少损失无关。Denning勋爵说：