For a contract to be concluded, the parties must obtain mutual consent (also known as meetings of minds). This is usually achieved through an offer and acceptance that does not change the terms of the offer, which is called a „mirror image rule”. An offer is a final statement of the bidder`s willingness to commit under certain conditions.  If an alleged acceptance changes the terms of an offer, it is not an acceptance, but a counter-offer and therefore a rejection of the original offer. The Uniform Commercial Code has the mirror image rule in § 2-207, although the UCC only regulates transactions of goods in the United States. Since a court cannot read minds, the intention of the parties is interpreted objectively from the point of view of a reasonable person, as noted in the first English case of Smith v. Hughes . It is important to note that if an offer indicates a certain type of acceptance, only an acceptance communicated by this method is valid.  True contract law – i.e. enforceable promises – implies the development of a market economy.
If the value of an obligation does not vary over time, the notions of ownership and infringement are reasonable and there will be no performance of an agreement if neither party has performance because no harm has been done with respect to the property. In a market economy, on the other hand, a person may seek an obligation today to protect himself from a change in value tomorrow; the person receiving such an undertaking feels aggrieved by the failure to comply with this obligation to the extent that the market value differs from the agreed price. On the other hand, domestic and social agreements such as those between children and parents are generally unenforceable on the basis of public order. For example, in the English case Balfour v Balfour, a husband agreed to give his wife £30 a month while away from home, but the court refused to enforce the agreement when the husband stopped paying. In contrast, in Merritt v. Merritt, the court enforced an agreement between a separated couple because the circumstances suggested that their agreement must have legal consequences. If a person performs an act by circumventing the law that would have the effect of nullifying the provisions of a law, then such acts would be considered illegal. So something that cannot be done directly cannot be done indirectly. In an agreement, commitments come from both sides, i.e. from the bidder and the target recipient. For example, A promises to deliver certain goods to B on a certain date, and B promises to pay from the same. In the United States, an unusual type of unenforceable contract is a personal employment contract to work as a spy or secret agent. Indeed, the secrecy of the contract is a condition of the contract (to maintain plausible deniability).
If the spy later sues the government over issues such as salary or benefits, the spy has broken the contract by revealing its existence. It is therefore unenforceable for this reason, as is the public policy of maintaining national security (since a disgruntled agent could attempt to expose all the secrets of the government at trial).  Other types of unenforceable employment contracts include contracts that agree to work for less than minimum wage and loss of entitlement to workers` compensation in cases where workers` compensation is due. Not all agreements are necessarily contractual, as the parties generally have to intend to be legally bound. A so-called gentlemen`s agreement is an agreement that is not legally enforceable and is supposed to be „only honorably binding.”    More generally, the authors advocated Marxist and feminist interpretations of treaties. Attempts have been made to achieve a comprehensive understanding of the object and nature of the treaty as a phenomenon, in particular the theory of relational contracts, originally developed by American contract scholars Ian Roderick Macneil and Stewart Macaulay, which was at least partly based on the theoretical work on contracts of the American academic Lon L. Fuller, while American researchers were at the forefront of the development of economic contract theories. , which focused on the issues of transaction costs and the so-called „effective breach” theory. Most countries have laws that deal directly with the sale of goods, leasing transactions and business practices.
In the United States, the most striking examples in the case of products are an implied warranty of merchantability and fitness for a particular purpose and, in the case of homes, an implied warranty of habitability. In a less technical sense, however, a condition is a generic term and a guarantee is a promise.  Not all languages of the contract are defined as a contractual clause. Representations, which are often pre-contractual, tend to be less strictly enforced than conditions, and substantial misrepresentations have always been a cause of action for the crime of deception. Safeguards were applied regardless of materiality; In modern U.S. law, the distinction is less clear, but safeguards can be applied more strictly.  Expressions of opinion can be considered a „mere puff.” However, if the part of the consideration or object of an agreement is lawful and the two are separable, that part of an agreement is valid. An injunction for a particular service and an injunction are discretionary remedies, most of which arise from equity. Neither is legally available, and in most jurisdictions and circumstances, a court will generally not order a specific execution. A contract for the sale of real estate is a notable exception. In most jurisdictions, the sale of real estate is enforceable by a specific performance. Even then, defending against an equitable lawsuit (such as laches, the bona fide buyer`s rule, or impure hands) can be an obstacle to a particular performance.
Statements of fact in a contract or when obtaining the contract are considered guarantees or insurance. Traditionally, warranties are promises of fact enforced through contractual suit, regardless of materiality, intent or trust.  Insurance is traditionally a pre-contractual statement that allows for a misdemeanour (p.B the misrepresentation) if the misrepresentation is negligent or fraudulent;  Historically, tort was the only action available, but in 1778, breach of warranty became a separate legal contractual measure.  In the United States. The difference between the two is unclear;  Warranties are primarily considered contract-based lawsuits, while negligent or fraudulent misrepresentations are tortious, but there is a confusing mix of jurisdictions in the United States.  In modern English law, sellers often avoid using the term „represented” to avoid claims under the Misrepresentation Act of 1967, whereas in America, „warrants and representations” are relatively common.  Some modern commentators suggest avoiding the words and replacing „state” or „consent,” and some standard forms do not use the words;  However, others disagree.  As noted above, only agreements that meet the condition set out in section 10 of the Indian Contracts Act become contracts. Similarly, an agreement whose consideration or object is fraud is illegal. Contracts are mainly subject to state law and general (judicial) law and private law (i.e.
private agreements). Private law essentially includes the terms of the agreement between the parties exchanging promises. This private right may prevail over many rules that are otherwise set by State law. Legal laws, such as the Fraud Act, may require certain types of contracts to be concluded in writing and executed with special formalities for the contract to be enforceable. Otherwise, the parties can enter into a binding agreement without signing a formal written document. For example, the Virginia Supreme Court in Lucy v. Zehmer said that even an agreement reached on a piece of towel can be considered a valid contract if the parties were both healthy and showed mutual consent and consideration. Each Party must be a „well-informed person” with legal capacity. The parties may be natural persons („natural persons”) or legal persons („companies”). An agreement is reached when an „offer” is accepted.
The parties must intend to be legally bound; and to be valid, the agreement must have both an appropriate „form” and a lawful purpose. In England (and in jurisdictions that apply the principles of English treaties), the parties must also exchange „considerations” to create „reciprocity of obligation,” as in Simpkins v Countries.  Each country recognized by private international law has its own national contract law. While contract law systems may have similarities, they may have significant differences. As a result, many contracts contain a choice of law clause and a jurisdiction clause. These provisions govern the laws of the country governing the contract or the country or other jurisdiction in which disputes are resolved. In the absence of explicit agreement on these issues in the treaty itself, countries have rules for determining the law applicable to the contract and jurisdiction over disputes. .