(1) According to the benefit-disadvantage theory, there is no reasonable consideration unless a promise is made in favour of the promisor or to the detriment of the promise, which reasonably and fairly induces the promisor to make a promise for something else for the promise. For example, promises that are pure gifts are not considered enforceable, because the personal satisfaction that the donor of the promise can receive through the act of generosity is not normally considered a sufficient disadvantage to justify fair consideration. 2) According to the Bargain-for Exchange theory of reflection, there is an appropriate consideration when a promiser makes a promise in return for something else. Here is the essential condition that the promisor was given something special to induce the promise made. Some exceptions to the common law, such as agency, assignment and negligence, allowed for some circumvention of ownership rules, but the unpopular doctrine remained intact until it was amended by the Contracts of Third Parties Act 1999, which provides: A person who is not a party (a third party) may impose a contract itself if: who is of an unhealthy mind, that is, who, at the time of approval, is not able to make a rational judgment, invalidates such an agreement with a person with an unhealthy mind. Thus, an agreement with a person who is usually of sound mind, but sometimes of unhealthy mind, leads to a valid contract if a person was in good health at the time of entering into the contract. The burden of proof that the person was not sound at the time the contract was concluded lies with the applicant. (v) Error: the acceptance of the contract is caused by an error during franchising – commercial agreements that allow one company to trade with a product or service controlled by another. Contracts are concluded when an obligation arises from a commitment of one of the parties. .