A declaration of intent made by a person who, for any reason, is in a state which precludes the conscious or free making of a decision and declaring of intent is invalid. This applies in particular to mental illness, mental retardation or other, even temporary, mental disorder.

But what if there are mistakes in declaration of will?

They can influence the consent in the formation of contracts and there is a large doctrine regarding mistakes in will.

For instance, a mistake about such characteristics of a person or a thing as are customarily regarded as essential is a mistake about the contents of the declaration.

Under the article 103 of the Principles of European Contract Law (also called PECL), a party may avoid a contract for mistake of fact or law existing when the contract was concluded if:

  1. a) the mistake was caused by information given by the other party; or the other party knew or ought to have known of the mistake and it was contrary to good faith and fair dealing to leave the mistaken party in error; or the other party made the same mistake, and
  2. b) the other party knew or ought to have known that the mistaken party, had it known the truth, would not have entered the contract or would have done so only on fundamentally different terms.

The distinction between a party’s declaration and his underlying will is relevant from a legal point of view. While the distinction between a party’s will and a mere motive is, in general, irrelevant, a discrepancy between a party’s declaration and his will led to the invalidity of the respective contract.

The contract, in fact, is regarded as well as an act of self-legislation that is subject to the tacit condition that all its assumptions are correct.

In ancient Roman Law, for instance, it was taught that “if I believe to buy the Cornelian real estate and you believe to sell the Sempronian one, the sale is void, because we differ about the body of the contract (the so called “error in corpora”)”.

Moreover, it is equivalent to a change of circumstances if material conceptions that have become the basis of the contract are found to be incorrect. Adaptation of the contract may be demanded. If adaptation of the contract is not possible, in the case of continuing obligations, the right to terminate takes the place of the right to withdraw.

Shall you have any comment or curiosity about the doctrine of mistakes in declaration of will during the formation of contract, please email us: info@dandreapartners.com.