In criminal law, the inchoate crime of conspiracy requires an agreement to commit an illegal act. An agreement in this context should not be explicit; On the contrary, the facts and circumstances of the case can rather be inferred from a meeting of spirits. As a general rule, courts are not in a position to balance the „proportionality“ of the consideration, provided that the consideration is determined as „sufficient“, the adequacy being defined as an exercise in legal review, while „adequacy“ is subjective fairness or equivalence. For example, consent to the sale of a car for a pfennig may constitute a binding contract (although the transaction is an attempt to avoid taxes, it is treated by the tax authorities as if a market price had been paid).  Parties may do so for tax purposes and attempt to conceal donations in the form of contracts. This is called the peppercorn rule, but in some legal systems, the penny may be an insufficient nominal consideration. An exception to the adequacy rule is money, a debt that must always pay in full for „compliance and satisfaction.“     In trade agreements, it is considered that the parties intend to be legally bound, unless the parties explicitly state otherwise, as in a contractual document. For example, in the Rose- Frank Co/JR Crompton-Bros Ltd case, an agreement between two commercial parties was not reached because the document stipulated an „honour clause“: „This is not a commercial or legal agreement, but only a declaration of intent by the parties.“ A contract is a legally binding document between at least two parties, which defines and regulates the rights and obligations of the parties to an agreement.  A contract is legally enforceable because it complies with the requirements and approval of the law.
A contract usually involves the exchange of goods, services, money or promises from one of them. „breach of contract“ means that the law must grant the victim either access to remedies, such as damages, or annulment.  Contract theory is the text that deals with normative and conceptual issues in contract law. One of the most important questions in contract theory is why contracts are applied. An important answer to this question focuses on the economic benefits of implementing bargains. Another approach, associated with Charles Fried, asserts that the purpose of contract law is to impose promises. This theory was developed in the book Fried Contract as Promise. Other approaches to contract theory can be found in the writings of critical lawyers and lawyers.