说明义务是指未经对方要求而主动告知对法律行为的做出具有重大影响的法律或事实情况的义务。在法无明文规定的情况下，缔约过程中说明义务的成立应诉诸诚实信用原则和交易惯例。在方法论层面，通过经济分析方法和动态系统论的引入，对缔约过程中说明义务成立与否的判断更具可操作性。通过偶然获得信息与有意获得信息以及生产性信息、再分配性信息、混合信息与安全信息两组理论模型，经济分析臻于完善；通过信息需求、信息可能性和职责范围三个要素，说明义务的动态系统模型得以建构。针对说明义务的违反，存在复数的规制路径，其相互之间呈现为竞合关系。对于合同废除请求权与欺诈撤销权之间的关系，自由竞合说、欺诈规定优先说均不尽完善，折衷方案较为合理。在我国的背景下，受误导人需借助欺诈撤销权或错误撤销权以摆脱合同的束缚。当缔约过程中说明义务的违反同时导致瑕疵给付时，根据德国现行理论，瑕疵担保责任原则上排除缔约过失责任的适用，唯在误导人故意的情形可成立请求权竞合或者择一的竞合。在我国，受误导人可以选择行使撤销权并主张缔约过失责任，或者径行要求误导人承担瑕疵担保责任。在维持合同效力的情况下，瑕疵担保责任排除缔约过失责任的适用。因违反缔约过程中说明义务所造成的损失属于纯粹经济损失，如存有特殊的侵权法规范，或者保护他人的法律、法规，应优先适用侵权责任。当误导人为故意时，应承认缔约过失责任与侵权责任的竞合。如果侵权法提供救济需要满足“故意背俗”的要件，则缔约过失责任可优先适用。在废除或撤销合同的情形，针对说明义务违反与合同缔结之间的因果关系，受误导人可援引优势盖然性标准、表见证据规则或证明责任倒置，以减轻证明责任。因徒劳支出的费用和交易机会损失均可能大于履行利益，故信赖利益赔偿不以履行利益为限。对于责任的限制可通过免责表示和与有过失规则予以实现。在维持合同效力的情况下，对合同的调整或变更可以信赖利益或履行利益为标准。如果缔约过程中说明义务的违反同时导致了对合同义务的违反，则受误导人可要求赔偿履行利益，减价规则也有发挥作用的空间。此时，受误导人就主张信赖利益和履行利益具有选择权。如果仅仅违反了缔约过程中的说明义务，则仅可基于缔约过失要求信赖损害赔偿。当事人可遵循意思自治原则，通过协议对合同进行调整或变更。同时，可考虑引入再交涉义务。当交涉不成时，方可要求法院或者仲裁机构调整或变更合同。
The duty to inform refers to the duty, according to which one party should take the initiative to inform the other party the legal or factual situation that have significant impacts on legal acts. In the absence of specific provisions of law, it should resort to the principle of good faith and trade practices to determine that whether duty to inform in contracting is established. In the methodological level, through the introduction of economic analysis and dynamic systems theory, the judgment of the duty to inform in contracting is more operational. By two theoretical models, namely access to information accidentally and access to information intentionally and production of information, redistribution of information, mixed information and safety information, the economic analysis is more perfected. By information needs, information possibilities and functional range, the dynamic system is constructed, which is used to judge whether there is a duty to inform or not. Although the dynamic system needs necessary correction, the defects can’t obscure the virtues. For the breach of duty to inform, there are plural regulatory paths, which are concurrence relationship. For the relationship between the claim to cancel contract and the right of revocation due to fraud, there are three theories, which are the theory of free concurrence, the theory of application of provision about fraud preferentially and the theory of compromise. The theory of free concurrence and the theory of application of provision about fraud preferentially are not blameless. In comparison, the theory of compromise is better. In China, it should resort to right of revocation due to fraud or significant misconception. If the breach of duty to inform in contracting leads to defective performance, warranty liability will exclude liability for fault in contracting according to the new German obligation law. Only in the case of intentional misleading, the misled person has right to choose between the two liabilities. In China, the misled person may choose to exercise the right to revoke and advocate liability for fault in contracting, or require that the misleader assumes warranty liability. But in the case of misleader’s being negligent, the particular provisions are required in order to advocate liability for fault in contracting. When the misled person maintains the validity of the contract, regardless he is intentionally or negligently misled, warranty liability will exclude liability for fault in contracting. The damages caused by breach of duty to inform belong to pure economic losses. If there are special provisions about tort law or laws and regulations to protect other person, tort liability shall prevail. When misleader is intentional, man should recognize the concurrence between liability for fault in contracting and tort liability. If it needs meet the element of "intentionally violate good morals" to apply tort law, liability for fault in contracting should prevail.After the cancel or revocation of contract, for the proof of Causality between breach of duty to inform and Conclusion of contract, the misled person can quote the standard of overwhelming probability, prima facie evidence or reversal of burden of proof to alleviate the burden of proof. Because futile expenses and opportunity losses are both likely to be greater than performance interests, so reliance interests should not be limited by performance interests. The limitation of liability can be realized by exemption expression and the contributory negligence rule. When the misled person maintains the validity of the contract, the adjustment or change of contract can be realized according to standard of reliance interest or performance interest. If the breach of duty to inform in contracting leads to breach of contract duty, the misled people can claim damages for performance interest. The rule of reducing price can also play a role in space. At this point, the misled person has the option to advocate damages for reliance interest or performance interest. If the misleader only violates the duty to inform in contracting, the misled can only advocate damages for reliance interest. Also the two parties can adjust or change the contract following the principle of autonomy. In this case, further negotiation duty could be introduced. When the negotiation fails, the misled person can request the court or arbitration body to adjust or change the contract.
