3. 对第三方行为的认定标准：概率加权评估法
The Approach to Third-Party Actions: Probability-Weighted Evaluation
英国判例法确立，当涉及第三方可能采取的行为时，法院将采用“概率加权评估法”来确定该第三方在反事实的假设情形中可能采取的行动，而不是采用盖然性权衡原则来评估。法院根据概率加权评估确定第三方采取相关行为的可能性，并据此按对应比例调整可获得赔偿金额。
The English case law establishes that where a contingency depends on the actions of third parties, courts adopt a probability-weighted approach to determine what a third party would have done in a hypothetical counterfactual scenario. Instead of requiring proof on the balance of probabilities, courts assess the likelihood of a third party’s conduct and adjust the amount of damages proportionally.
法律逻辑 Legal Rationale
由于第三方不受合同关系的约束，其行为缺乏可预测性，无法通过“理性自利”的推定加以判断。因此，在反事实的假设情形中对第三方假设行为的评估本质上具有推测性，需对（各种）可能性做出评估性的判断。如Perry v Raleys Solicitors [2020] AC 352（“Perry诉Raleys Solicitors案”）所述，法院已发展出一条清晰且符合常理的划分标准，划分应由当事人举证证明的事项，以及通过"机会丧失"的评估来判定的事项。若要证明客户在获得适当建议后本可避免损失，该证明依赖于推测客户当时可能采取的行动，则原告须基于盖然性权衡原则承担举证责任（即证明客户采取原告所主张的行为的可能性更高）。反之，若预期有利后果的实现依赖于第三方的假设行为，其判定便有赖于对"机会丧失"的评估。
Third parties operate outside the contractual relationship, introducing uncertainty that cannot be resolved by presuming rational self-interest. The assessment of hypothetical third-party conduct is inherently speculative and requires an evaluative judgment of the chances. As noted in Perry v Raleys Solicitors [2020] AC 352 (“Perry v Raleys Solicitors”), courts have developed a clear and commonsense dividing line between those matters which the client must prove, and those which may better be assessed upon the basis of the evaluation of a lost chance. To the extent (if at all) that the question whether the client would have been better off depends upon what the client would have done upon receipt of competent advice, this must be proved by the claimant upon the balance of probabilities. To the extent that the supposed beneficial outcome depends upon what others would have done, this depends upon a loss of chance evaluation (Perry v Raleys Solicitors, at [20]).
权威判例 Case Law Authority
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Aercap Partners诉Avia Asset Management案：法院认定，第三方行为（如监管审批）应基于其发生机会的评估予以认定；对于因取决于第三方行为的既往假设性事件而产生的因果关系问题，“机会丧失”原则应予适用，若某既往假设性事件的结果取决于某第三方的行为，原告有权就第三方本将依此行事之机会受损主张赔偿。“机会丧失”原则能为原告带来利益是不言自明的（而这正是Allied Maples案裁决的核心依据）（Aercap Partners 诉Avia Asset Management案第76段(iii)）。
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Aercap Partners v Avia Asset Management: The court held that third-party actions (e.g. regulatory approvals) should be assessed by evaluating the chances of their occurrence. It concluded that, the loss of a chance doctrine is applicable to questions of causation arising out of hypothetical past events hinging on the act of a third party. And where the outcome of a hypothetical past event depends on what a third party would have done, the claimant may recover for loss of the chance that the third party would have so acted. That the loss of a chance doctrine may thus benefit a claimant is apparent (and indeed underlies the decision in Allied Maples) (Aercap Partners v Avia Asset Management, at [76(iii)]).
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Wellesley Partners LLP诉Withers LLP案：法官首先基于盖然性权衡原则认定原告Wellesley有可能在美国设立办事处，继而就其能否从野村银行取得业务委托进行了概率评估，最终认定该概率为60%。法院根据该概率（包括其他因素）判定，Wellesley因未能获得该业务委托而遭受的利润损失，按该概率予以赔偿60%。法官的上述方法在上诉法院的判决中获得维持（Wellesley Partners LLP 诉 Withers LLP案第47–50、109–110段）。
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Wellesley Partners LLP v Withers LLP: After the judge concluded on the balance of probabilities that Wellesley would have opened a US office, he then went on to evaluate the chances of Wellesley obtaining mandates from Nomura bank, arriving at a 60% probability thereof. And the judge awarded damages for lost profits on the basis of, inter alia, a 60% chance of obtaining business with Nomura bank. The judge’s approach was upheld on appeal (Wellesley Partners LLP v Withers LLP, at [47] – [50], [109] – [110]).
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Assetco plc v Grant Thornton UK LLP [2019] EWHC 150 (Comm)（“Assetco plc诉Grant Thornton UK LLP案”）: 法院援引了Maden v Clifford Copock & Carter [2004] EWCA Civ 1037（“Maden诉Clifford Copock & Carter案”）。在该案中，上诉法院推翻了一审法院关于损害赔偿金额的判决，一审法院就相关第三方的行为根据盖然性平衡原则认定和解本会发生，上诉法院经评估认为和解的概率是80%，依据该高度可能性的概率对损害赔偿金额下调20%。原告（如按一审判决）本可获得其主张的100%的损害赔偿金额，但上诉法院发现（一审法院）使用的方法是错误的（Assetco plc诉Grant Thornton UK LLP案第413段）。
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Assetco plc v Grant Thornton UK LLP [2019] EWHC 150 (Comm)(“Assetco plc v Grant Thornton UK LLP”): The court referred to Maden v Clifford Copock & Carter [2004] EWCA Civ 1037 (“Maden v Clifford Copock & Carter”), in which the Court of Appeal reversed the decision of the trial judge at first instance in failing to apply a discount at the quantum stage in relation to the actions of the third party where the trial judge had found "on balance of probabilities" that a settlement would have occurred, the prospects being "high" with the Court of Appeal discounting the amount recoverable by 20% on the basis of an assessment of the likelihood of settlement at 80%. The claimant would have been entitled to 100% of the damages claimed – but as the court found that was not the correct approach (Assetco plc v Grant Thornton UK LLP, at [413]).
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Phoenicks Ltd诉Property案：概括而言，核心要点是，当原告主张“机会丧失”的损害赔偿且其所受损失之因果关系取决于第三方在假设情境下可能作出的行为时，原告须证明该等第三方作出特定行为具有真实或实质性的可能性，而非纯属臆测性的概率。对上述行为发生概率的评估为损失赔偿金额量化评估的一部分。无论在评估因果关系时可能性有多大，此类情形下，原告不得另行选择以盖然性权衡原则证明第三方确会作出该行为，并据此请求100%赔偿。至于法院是否实际听取了该第三方出庭作证，并无差别（Phoenicks Ltd诉Property案，第103段）。
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Phoenicks Ltd v Property: An essence is summarized that, where a claimant claimed “loss of a chance” damages, and the causation of the loss suffered by the claimant as a result of the defendant's wrongful act was dependent upon the hypothetical action of a third party, the claimant was required to prove that there was a real or substantial chance, as opposed to a speculative one, of the third party acting in a particular way, and the evaluation of that chance was then part of the assessment of the quantum of damages whatever the probability at the causation stage, that a claimant in such circumstances was not permitted to elect instead to seek to prove the action of third parties on a balance of probability and then to recover 100% of its damages, and whether the court heard from the third party appearing as a witness made no difference (Phoenicks Ltd v Property, at [103]).
英国判例法明确，当损害赔偿的评估涉及某第三方在假设情形下会作出何种行为的或然事件时，法院或仲裁庭应对第三人该等行为发生的概率作出评估，并据此确定一个可能性程度的百分比。
It is well-established in English case law that insofar as the contingency is as to what a third party would have done, the court or tribunal assessing damages needs to evaluate the chances of what the third party would have done, arriving at a percentage of probability thereof.
当评估合同当事人自身在反事实的假设情形中的行为时适用盖然性权衡原则，而评估第三方在反事实的假设情形中的行为时则适用概率加权评估法。然而，在某些具体情境中，合同当事人与第三方之间的界限可能并不清晰。例如，合同一方的雇员、顾问、董事、家庭成员或关联方，他们应被作为合同当事人还是第三方？
While the balance of probabilities test applies when assessing the hypothetical conduct of contracting parties, a probability-weighted approach governs the evaluation of third-party actions in counterfactual scenarios. However, the distinction between contracting parties and third parties may prove ambiguous in certain contexts. For instance, should employees, advisors, directors, family members, or affiliates of a contracting party be treated as contracting parties or third parties for this purpose?
概括而言，就前述讨论事项而言，“合同当事人”应包括其代理人及其他行为可归责于合同当事人的个人，但不包括与合同当事人拥有不同利益的人员（McGregor on Damages，§11-044、§11-070、§11-072；Assetco plc诉Grant Thornton UK LLP案，第452–453段）。正如 McGregor on Damages在§11-072中指出：“例如，当一家公司因自身行为失当而向被告寻求赔偿时，其董事应被视同索赔方（公司）本身，还是应被视同第三方？答案很可能取决于该董事的行为是否可归责于公司，如是，则该董事的行为即应被视为一方当事人（公司）自身的行为”。
In summary, for the purposes outlined above, a "contracting party" should include its agents and other individuals whose actions would be attributable to it, but exclude those who had divergent interests from the contracting party (see McGregor on Damages, at §11-044, §11-070, §11-072; Assetco plc v Grant Thornton UK LLP, at [452] – [453]). As noted in §11-072 of McGregor on Damages, “[f]or instance, is a director to be treated in the same way as the claimant or as a third party where the claimant is a company seeking recovery from a defendant for breach of duty by the company? The answer should probably depend upon whether the actions of the director are attributable to the company, in which case the director’s conduct is the conduct of a party”.
或有损害赔偿金额的确定
Determination of Contingent Damages
在完成对反事实的假设情形中相关第三方行为的概率加权评估后，法院将根据评估确定的概率来确定损害赔偿金额。
Following a probability-weighted evaluation of the relevant third party's action in the counterfactual scenario, courts will determine damages by applying the weighted probabilities.
正如前述 Maden诉Clifford Copock & Carter案所示，法院指出，基于盖然性权衡原则而认定某一第三方行为（和解）本会发生是错误的。法院在该案中评估该和解行为发生的可能性为80%，并据此对可获得赔偿金额作出20%的折减，以反映该或然事件（和解）有20%的不能实现的可能性。
As explained above in the case of Maden v Clifford Copock & Carter, the judge found that assuming a third-party action (a settlement) would have occurred based on the balance of probabilities was incorrect. Instead, the judge assessed the likelihood of settlement at 80%, and accordingly applied a 20% discount to the recoverable damages, which corresponds to the 20% chance that the contingent event (the settlement) would not have occurred.
在笔者曾代理的某合同适用法为英国法的国际仲裁案件中，仲裁庭评估了被申请人寻求服务的银行（在后续如合同继续履行时）拒绝开立信用证的可能性，并确定了具体的可能性的百分比；在合同项下，如出现上述银行拒绝服务的情形将触发合同不可抗力条款的适用。仲裁庭基于盖然性权衡原则认定，被申请人届时如遭银行拒绝，将会主张不可抗力免责；针对申请人所主张的损失赔偿，仲裁庭进一步认为，在计算预期利益损失金额时，应根据被申请人在上述情形下无法获得信用证的概率，对损失金额予以相应折减，以反映被申请人不能获得银行服务的风险（非其所能控制）。仲裁庭在损害赔偿金额量化确定时明确适用了上述具体百分比对损害赔偿金额打折。
In an international arbitration case (dealing with disputes arising from a contract governed by English law) the author represented, the tribunal assessed the probability at a certain percentage that the banks the defendant approached would have refused to issue a letter of credit, which may trigger the application force majeure clause under the contract. On the balance of probabilities, the Tribunal was satisfied that the defendant would then have invoked the force majeure clause upon the bank’s refusal to issue the letter of credit. And accordingly, noting the claimant’s losses, the tribunal determined that the claimant’s loss of bargain should include a discount corresponding to that probability to reflect the very significant risk that a letter of credit could not have been obtained by the defendant in the prevailing circumstances. That discount was clearly applied in the tribunal’s conclusion on quantum.
4.结论及实务启示
Conclusion with Practical Implications
综上所述，英国法对反事实的假设情形下的或有事件采用不同的评估方法：
In summary, the English law adopts distinct methodologies for assessing counterfactual contingencies:
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对合同当事人的行为，应基于盖然性权衡原则予以评估，因为其行为可基于合同及商业现实预测。因此，损害赔偿金额应基于“全有或全无”的原则确定。
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Contracting parties’ actions should be resolved on the balance of probabilities, because their conduct is considered predictable according to contractual and commercial realities. Consequently, damage should be determined on an 'all or nothing' basis.
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对第三方的行为，则应采用概率加权评估法予以评估，以反映外部行为主体的行为所固有的不确定性。如果第三方具有减少或消除损失效果的行为发生的可能性达到一定不可忽视的比例，则应相应按比例减少损害赔偿金额。
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Third-party actions should be evaluated applying a probability-weighted approach to reflect the inherent uncertainty of external actors’ behaviour. If the likelihood of a third-party contingency reducing or extinguishing loss is assessed at a certain non-negligible percentage, damages should be proportionately reduced.
针对不同类型的或然事件分别采用不同的评估方法，旨在确保赔偿金额与索赔方的实际损失相符，避免出现赔偿不足或意外获得暴利的情形。正如The Golden Victory案所强调，法律的普遍意图并非重构一个理想化的世界，而是将索赔方置于合同如继续履行其所处于的同样的位置，所有可能导致其预期利益损失减少或消灭的可能性均应予以考虑（The Golden Victory案第30、74段）。
This distinction in assessment methodologies ensures that damages are proportionate to the claimant’s actual loss and avoids under-compensation and speculative windfalls. As emphasized in The Golden Victory, the general intention of the law is not to reconstruct an idealized world, but to place the claimant in the same position as he would have been in if the contract had been performed, and all contingencies which might have reduced or extinguished the loss must be taken into account (The Golden Victory, at [30], [74]).
毫无疑问，评估在反事实的假设情形下合同当事人或第三方的假设行为非常困难，尤其是涉及第三方行为时更为复杂。然而，法院的日常职责是查明现实中实际发生之事实，而非通常被称为“反事实”的假设情形下可能发生的事实（Perry诉Raleys Solicitors案，第20段）。为实现上述目标，法院通常会综合考虑事实证据与专家证据，并就相关当事人或第三方在特定情境中是否可能作出某种行为进行交叉盘问，并结合行为人的惯常模式、过往行为、当时市场惯例及其他类似因素进行评估。因此，当事人（在参与争议解决或主张赔偿时）有必要遵循前述不同的标准和方法，根据反事实的假设情形中有关或然事件或行为的性质，做好索赔策略和扎实的准备。各方也需根据其立场考虑不同的策略和侧重点。
Undoubtedly, the assessment of either contracting parties’ actions or third-party actions in counterfactual contingencies would be very difficult, especially when it comes to third-party actions. Nevertheless, the everyday task of the court is to determine what, in fact, happened in the real world rather than what probably would have happened in a what-if scenario generally labelled the counterfactual (Perry v Raleys Solicitors, at [20]). Courts, for that purpose, take into account factual and expert evidence, as well as cross-examination regarding whether the parties or third parties would have done something or not, considering their habitual patterns, prior conduct, contemporaneous market practice and similar factors. Therefore, it’s important for the parties to follow the above-mentioned distinction and make strategic and solid preparations by tailoring arguments to the nature of contingencies. Each party may also need to assess its strategy and key issues from its own standpoint.
从索赔方的角度出发
From the Claimant's Perspective
对于索赔方或其代理律师而言，在准备其案件时，首先评估合同当事人或第三方在反事实的假设情形（if any）中的行为的概率至关重要。
For a claimant or its counsel, it is essential to prepare the case by first evaluating the probabilities of actions by the parties or third parties in a counterfactual (if any).
针对当事人在假设情形下的行为，例如主张的被索赔方本会行使某项选择权的情形，应努力构建由证据链支撑的事实陈述。具体而言，可收集具有关联性的同期记录（如电子邮件、内部备忘录等）以及行业惯例，以论证该相关方（例如被索赔方）可能作出的行为。此外，以其既往行为（例如既有合同履行情况或类似交易模式）增强对其未来行为预测的可信度。
For party-dependent contingencies, such as alleging that the defendant would have exercised an option, it is advisable to construct an evidence-based narrative. By collecting contemporaneous records (e.g., emails and internal memos) and industry practices, the probable conduct of the relevant party (e.g., the defendant) can be demonstrated. Furthermore, leveraging historical behavior (e.g., past contract performance or similar transactional patterns) can justify assumptions about the relevant party's future actions.
针对第三方在假设情形下的行为，如基于假设供应商会做出某个决定而索赔利润损失，通过专家报告帮助量化概率尤为关键（例如使用经济模型来显示合同续签的概率百分比）。即使专家无法提供具体百分比，其专业能力、信誉及行业知识也可帮助法院或仲裁庭确定一个概率百分比。此外，预先回应和消除可能的质疑，特别是通过援引司法实践中接受的基于实证数据的概率评估，也是一种策略性的方式。
In the case of third-party contingencies, such as claiming lost profits due to a supplier's hypothetical decision, quantifying probabilities through expert reports (e.g., econometric models showing the percentage chance of contract extension) can be very helpful. Even if experts cannot determine a specific percentage, their credibility, expertise, and industry-specific knowledge may assist the courts or tribunal in establishing a percentage. Additionally, preemptively addressing challenges by citing judicial acceptance of probabilistic valuations supported by empirical evidence is a strategic approach.
从被索赔方的角度出发
From the Defendant’s Perspective
对于被索赔方而言，不要被认定为有违约责任便在赔偿金额量化阶段放弃，仍然可能有重要的抗辩空间。被索赔方通过以下策略仍有机会减轻赔偿责任：
For defendants, liability findings do not equate to unconditional surrender on quantum. Significant opportunities remain to mitigate damages by:
（1）削弱盖然性平衡（可能性程度）
例如，被索赔方可以主张索赔方关于自己行为的假设仅为猜测（特别是在其没有充分的证据时），也可以对比索赔方在类似合同项下的过往履约表现，或考察其在履行其他义务方面的实际情况，以说明索赔方主张的支持其索赔的特定事件发生的可能性不足51%，从而不能满足盖然性权衡原则的标准。
(i) Undermining the balance of probabilities. For example, the defendant may argue that the claimant’s assumptions about their own actions are speculative, particularly where there is insufficient evidence to support them. The defendant may also compare the claimant’s actions with its previous performance of similar contracts or evaluate the claimant’s performance in different aspects of their obligations to show the impossibility or a less than 51% possibility of certain events that may substantiate the claimant’s claims.
（2）充分展示有关第三方行为的不确定性
被索赔方可提交第三方在类似情形下既往行为的证据（例如，监管机构对类似申请的驳回率），援引相关判例法，以降低有关第三方行为的可能性比例，相应减少赔偿金额。例如，在Assetco plc诉Grant Thornton UK LLP案中，法院认定监管机构驳回申请的可能性为20%，因而在赔偿数额上作出相应20%的扣减（Assetco plc诉Grant Thornton UK LLP案第413段）。
(ii) Showing uncertainties of relevant third-party actions. The defendant may submit evidence of third parties’ historical conduct in analogous scenarios (e.g., a regulator’s rejection rate of similar applications) to justify proportionate reductions of damages and invoke case law authorities, such as Assetco plc v Grant Thornton UK LLP, where a 20% chance of regulatory refusal warranted a 20% damages reduction (Assetco plc v Grant Thornton UK LLP, at [413]).
（3）主张对损害赔偿的法律限制
例如，在The Golden Victory案中，法院明确赔偿范围应、限于可证实的损失（“索赔方有权获得其所丧失的合同权利所对应的金钱利益，但无权获得超出其所实际丧失合同权利的更大价值之利益”），从而排除纯属臆测的潜在利益（The Golden Victory案第30段）。若该等利益的实现依赖于相关合同方或第三方之行为，则须分别基于盖然性权衡原则或概率加权评估法证明相关行为发生的可能性，证明的可能性程度将决定损害赔偿金额全部被支持或根本不被支持（因果关系取决于合同当事人的假设行为时），或者按相应比例得到支持（因果关系取决于相关第三人的行为时），以反映即使违约未发生合同预期利益也可能不能获得或不能全部获得的风险。
(iii) Invoking judicial restraint on damages. For example, in The Golden Victory, the recovery was confined to provable losses (“the claimant is entitled to the benefit, expressed in money, of the contractual rights he has lost, but not to the benefit of more valuable contractual rights than those he has lost”), thereby excluding speculative gains (The Golden Victory, at [30]). If the obtaining of those benefits depends on the actions of a relevant contracting party or third party, proving the probability of such actions using the balance of probabilities or a probability-weighted approach, respectively, will essentially result in that the claimant’s alleged damages are either not recoverable at all on an “all or nothing” basis or not fully recoverable subject to probability-weighted reduction. This reflects that the benefits would not be obtained or there would be certain risks of not obtaining them, even if the breach had not occurred.
总之，无论是索赔方还是被索赔方，成败的关键在于将证据与适用的法律标准相契合。具体而言，在适用盖然性权衡原则时，借助书面证据证明合同当事人在假设情形下会采取的行为；在适用“概率加权评估法”时，借助数据模型推演第三方在假设情形下可能作出的行为。通过将主张紧扣上述法律标准，不仅在法律精确性与商业实用性之间实现平衡，还可能提升争议解决的效率与公平性。
In summary, for either party, success hinges on aligning evidence with the governing standard. That is, whereas the balance of probabilities requires documentary proof of what parties would have done, the probability-weighted evaluation requires data-driven models of what third parties might have done. By anchoring arguments to these thresholds, practitioners can achieve outcomes that not only reconcile legal precision with commercial pragmatism but also enhance the effectiveness and fairness of dispute resolutions.
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