Causal motive and its legal significance in contract law

The author of this article analyses the problem of motives for entering into a contact and their legal significance and systematically considers the impact of an error in motive on the legal validity of a contract in German law as well as in Russian law. In German law, an error in the properties of a person or an object is regarded by some experts as a mistake in the motive that testifies to its legal significance. In Russian law, in addition to an error in the object, the mistake in the motive is an error in regard to a circumstance that a party mentions in its expressed will or on which it bases itself evidently to another party when entering into a contract. The article also explores situations of subsequent failure to fulfill the motive in light of national (German and Russian) doctrines of the influence of a subsequent change of circumstances on the contract’s fate. The author concludes that the criterion which make it possible to distinguish a legally relevant motive from motives that have no legal significance is characteristic of the causality of the motive. The causality of the motive presumes that such a motive served as a key factor in predetermining the decision of the interested party to enter into a contract. It is the error in the causal motive or its subsequent non-implementation that affects the dynamics of the contract and it can lead to the effective avoidance of a contract or its termination (alteration) accordingly. The author also compares the consequences of non-implementation of a motive in civil law and the English doctrine “frustration of purpose”. In English law, non-implementation of a motive according to the doctrine of “frustration of purpose” leads to the automatic termination of a contact. On the basis of mentioned research, the author concludes that the common criterion in civil and English law that stipulates the legal effect of the error in motive or its nonimplementation is the causality of the motive.