Law and Contract.


A contract is a legally enforceable agreement between two or more parties with mutual obligations. The remedy at law for breach of contract is “damages” or monetary compensation. In equity, the remedy can be specific performance of the contract or an injunction. Both remedies award the damaged party the “benefit of the bargain” or expectation damages, which are greater than mere reliance damages, as in promissory estoppel.Contract law is based on the principle expressed in the Latin phrase pacta sunt servanda, which is usually translated “agreements to be kept” but more literally means “pacts must be kept”.[1]Contract law can be classified, as is habitual in civil law systems, as part of a general law of obligations, along with tort, unjust enrichment, and restitution.

As a means of economic ordering, contract relies on the notion of consensual exchange and has been extensively discussed in broader economic, sociological, and anthropological terms (see “Contractual theory” below). In American English, the term extends beyond the legal meaning to encompass a broader category of agreements.[2]

This article mainly concerns the common law. Such jurisdictions usually retain a high degree of freedom of contract, with parties largely at liberty to set their own terms. This is in contrast to the civil law, which typically applies certain overarching principles to disputes arising out of contract, as in the French Civil Code. However, contract is a form of economic ordering common throughout the world, and different rules apply in jurisdictions applying civil law (derived from Roman law principles), Islamic law, socialist legal systems, and customary or local law.At common law, the elements of a contract are mutual assent and consideration.

  1. Hans Wehberg, Pacta Sunt Servanda, The American Journal of International Law, Vol. 53, No. 4 (Oct.,  1959), p.775.; Principle of Sanctity of contracts
  1. 2008 Merriam-Webster online dictionary

Mutual assent

At common law, mutual assent is typically reached through offer and acceptance, that is, when an offer is met with an acceptance that is unqualified and that does not vary the offer’s terms. The latter requirement is known as the “mirror image” rule. If a purported acceptance does vary the terms of an offer, it is not an acceptance but a counteroffer and, therefore, simultaneously a rejection of the original offer. The Uniform Commercial Code notably disposes of the mirror image rule in § 2-207, although the UCC only governs transactions in goods.

Offer and acceptance

The most important feature of a contract is that one party makes an offer for an arrangement that another accepts. This can be called a concurrence of wills or consensus ad idem (meeting of the minds) of two or more parties. The concept is somewhat contested. The obvious objection is that a court cannot read minds and the existence or otherwise of agreement is judged objectively, with only limited room for questioning subjective intention: see Smith v. Hughes.[3] Richard Austen-Baker has suggested that the perpetuation of the idea of ‘meeting of minds’ may come from a misunderstanding of the Latin term ‘consensus ad idem’, which actually means ‘agreement to the [same] thing’.[4] There must be evidence that the parties had each from an objective perspective engaged in conduct manifesting their assent, and a contract will be formed when the parties have met such a requirement.[5] An objective perspective means that it is only necessary that somebody gives the impression of offering or accepting contractual terms in the eyes of a reasonable person, not that they actually did want to form a contract.

  1. (1870-71) LR 6 QB 597
  2. R. Austen-Baker, ‘Gilmore and the Strange Case of the Failure of Contract to Die After All’ (2002) 18 Journal of Contract Law 1
  3. e.g. Lord Steyn, ‘Contract Law: Fulfilling the Reasonable Expectations of Honest Men’ (1997) 113 LQR 433; c.f. § 133 BGB in Germany, where “the actual will of the contracting party, not the literal sense of words, is to be determined”

Offer and acceptance does not always need to be expressed orally or in writing. An implied contract is one in which some of the terms are not expressed in words. This can take two forms. A contract which is implied in fact is one in which the circumstances imply that parties have reached an agreement even though they have not done so expressly. For example, by going to a doctor for a checkup, a patient agrees that he will pay a fair price for the service. If one refuses to pay after being examined, the patient has breached a contract implied in fact. A contract which is implied in law is also called a quasi-contract, because it is not in fact a contract; rather, it is a means for the courts to remedy situations in which one party would be unjustly enriched were he or she not required to compensate the other. For example, a plumber accidentally installs a sprinkler system in the lawn of the wrong house. The owner of the house had learned the previous day that his neighbor was getting new sprinklers. That morning, he sees the plumber installing them in his lawn. Pleased at the mistake, he says nothing, and then refuses to pay when the plumber delivers the bill. Will the man be held liable for payment? Yes, if it could be proven that the man knew that the sprinklers were being installed mistakenly, the court would make him pay because of a quasi-contract. If that knowledge could not be proven, he would not be liable. Such a claim is also referred to as “quantum meruit“.


[6]Consideration must move from the promisee. For instance, it is good consideration for person A to pay person C in return for services rendered by person B. If there are joint promisees, then consideration need only to move from one of the promisees.

  1. Law Dictionary

Other jurisdictions

Some common-law and civil-law systems[7] do not require consideration, and some commentators consider it unnecessary—the requirement of intent by both parties to create legal relations by both parties performs the same function under contract. The reason that both exist in common law jurisdictions is thought by leading scholars to be the result of the combining by 19th century judges of two distinct threads: first the consideration requirement was at the heart of the action of assumpsit, which had grown up in the Middle Ages and remained the normal action for breach of a simple contract in England & Wales until 1884, when the old forms of action were abolished; secondly, the notion of agreement between two or more parties as being the essential legal and moral foundation of contract in all legal systems, promoted by the 18th century French writer Pothier in his Traite des Obligations, much read (especially after translation into English in 1805) by English judges and jurists. The latter chimed well with the fashionable will theories of the time, especially John Stuart Mill‘s influential ideas on free will, and got grafted on to the traditional common law requirement for consideration to ground an action in assumpsit.[8]


In addition to the elements of a contract:

v     a party must have capacity to contract;

v     the purpose of the contract must be lawful;

v     the form of the contract must be legal;

v     the parties must intend to create a legal relationship; and

v     the parties must consent.

For some contracts formalities must be complied with under legislation sometimes called a statute of frauds (especially transactions in real property or for relatively large cash amounts).

  1. e.g. In Germany, § 311 BGB
  2. For a detailed and authoritative account of this process, see A. W. B. Simpson, A History of the Common Law of Contract: The Rise of the Action of Assumpsit, (Oxford University Press: Oxford, 1975).

Freedom to contract and Hurley v. Eddingfield of the most famous cases on invitation to treat is Carlill v. Carbolic Smoke Ball Company,[9] decided in nineteenth-century England. A medical firm advertised that its new wonder drug, a smoke ball, would prevent those who used it according to the instructions from catching the flu, and if it did not, buyers would receive £100 and said that they had deposited £1,000 in the bank to show their good faith. When sued, Carbolic argued the ad was not to be taken as a serious, legally binding offer. It was merely an invitation to treat, and a gimmick (a ‘mere puff’). But the court of appeal held that it would appear to a reasonable man that Carbolic had made a serious offer, primarily because of the reference to the £1000 deposited into the bank. People had given good “consideration” for it by going to the “distinct inconvenience” of using a faulty product. “Read the advertisement how you will, and twist it about as you will,” said Lindley LJ, “here is a distinct promise expressed in language which is perfectly unmistakable”.

Intention to be legally bound

There is a presumption for commercial agreements that parties intend to be legally bound (unless the parties expressly state that they do not want to be bound, like in heads of agreement). On the other hand, many kinds of domestic and social agreements are unenforceable on the basis of public policy, for instance between children and parents. One early example is found in Balfour v. Balfour.[10] Using contract-like terms, Mr. Balfour had agreed to give his wife £30 a month as maintenance while he was living in Ceylon (Sri Lanka). Once he left, they separated and Mr. Balfour stopped payments. Mrs. Balfour brought an action to enforce the payments. At the Court of Appeal, the Court held that there was no enforceable agreement as there was not enough evidence to suggest that they were intending to be legally bound by the promise.

  1. [1893] 2 QB 256
  2. Balfour v. Balfour [1919] 2 KB 571
  3. Merritt v. Merritt [1970] 2 All ER 760; [1970] 1 WLR 1211; CA

The case is often cited in conjunction with Merritt v. Merritt.[11] Here the court distinguished the case from Balfour v. Balfour because Mr. and Mrs. Merritt, although married again, were estranged at the time the agreement was made. Therefore any agreement between them was made with the intention to create legal relations.

Formalities and writing

Oral contracts are ordinarily valid and therefore legally binding.[12] However, in most jurisdictions, certain types of contracts must be reduced to writing to be enforceable. This is to prevent frauds and perjuries, hence the name statute of frauds. For example, an unwritten contract would be unenforceable if for the sale of land.

Contracts that do not meet the requirements of common law or statutory Statutes of frauds are unenforceable, but are not necessarily thereby void. However, a party unjustly enriched by an unenforceable contract may be required to provide restitution for unjust enrichment. Statutes of frauds are typically codified in state statutes covering specific types of contracts, such as contracts for the sale of real estate.

In Australia and many, if not all, jurisdictions which have adopted the common law of England, for contracts subject to legislation equivalent to the Statute of frauds,[13] there is no requirement for the entire contract to be in writing. Although for property transactions there must be a note or memorandum evidencing the contract, which may come into existence after the contract has been formed. The note or memorandum must be signed in some way, and a series of documents may be used in place of a single note or memorandum. It must contain all material terms of the contract, the subject matter and

  1. international principle
  2. In Australia it is known as the Sales of Goods Act in most states, and in Victoria the Goods Act 1958

the parties to the contract. In England and Wales, the common law Statute of frauds is only now in force for guarantees, which must be evidenced in writing, although the agreement may be made orally. Certain other kinds of contract must be in writing or they are void, for instance, for sale of land under s. 52, Law of Property Act 1925. If a contract is in a written form, and somebody signs it, then the signer is typically bound by its terms regardless of whether he has actually read it,[14] However, affirmative defenses such as duress or unconscionability may enable the signer to avoid his purported obligation. Furthermore, if a party wishes to use a document as the basis of a contract, reasonable notice of its terms must be given to the other party prior to their entry into the contract.[15] This includes such things as tickets issued at parking stations.

Bilateral and unilateral contracts

Contracts may be bilateral or unilateral. A bilateral contract is the kind of contract that most people think of when they think “contract” and indeed represents the vast majority of contracts. It is an agreement in which each of the parties to the contract makes a promise or set of promises to the other party or parties. For example, in a contract for the sale of a home, the buyer promises to pay the seller $200,000 in exchange for the seller’s promise to deliver title to the property.

In a unilateral contract, only one party to the contract makes a promise. A typical example is the reward contract: A promises to pay a reward to B if B finds A’s dog. B is not under an obligation to find A’s dog, but A is under an obligation to pay the reward to B if B does find the dog. The consideration for the contract here is B’s reliance on A’s promise or B giving up his legal right to do whatever he wanted at the time he was engaged in the finding of the dog.

  1. Curtis v. Chemical Cleaning and Dyeing Co [1951] 1 KB 805
  2. Balmain New Ferry Company Ltd v. Robertson (1906) 4 CLR 379

In this example, the finding of the dog is a condition precedent to A’s obligation to pay, although it is not a legal condition precedent, because technically no contract here has arisen until the dog is found (because B has not accepted A’s offer until he finds the dog, and a contract requires offer, acceptance, and consideration), and the term “condition precedent” is used in contract law to designate a condition of a promise in a contract. For example, if B promised to find A’s dog, and A promised to pay B when the dog was found, A’s promise would have a condition attached to it, and offer and acceptance would already have occurred. This is a situation in which a condition precedent is attached to a bilateral contract.

Condition precedents can also be attached to unilateral contracts, however. This would require A to require a further condition to be met before he pays B for finding his dog. So, for example, A could say “If anyone finds my dog, and the sky falls down, I will give that person $100.” In this situation, even if the dog is found by B, he would not be entitled to the $100 until the sky falls down. Therefore the sky falling down is a condition precedent to A’s duty being actualized, even though they are already in a contract, since A has made an offer and B has accepted.

In unilateral contracts, the requirement that acceptance be communicated to the offeror is waived unless otherwise stated in the offer. The offeree accepts by performing the condition, and the offeree’s performance is also treated as the price, or consideration, for the offeror’s promise. The offeror is master of the offer; it is he who decides whether the contract will be unilateral or bilateral. In unilateral contracts, the offer is made to the public at large.

A bilateral contract is one in which there are duties on both sides, rights on both sides, and consideration on both sides. If an offeror makes an offer such as “If you promise to paint my house, I will give you $100,” this is a bilateral contract once the offeree accepts. Each side has promised to do something, and each side will get something in return for what they have done.

Uncertainty, incompleteness and severance

If the terms of the contract are uncertain or incomplete, the parties cannot have reached an agreement in the eyes of the law.[16] An agreement to agree does not constitute a contract, and an inability to agree on key issues, which may include such things as price or safety, may cause the entire contract to fail. However, a court will attempt to give effect to commercial contracts where possible, by construing a reasonable construction of the contract.[17]

Courts may also look to external standards, which are either mentioned explicitly in the contract[18] or implied by common practice in a certain field.[19] In addition, the court may also imply a term; if price is excluded, the court may imply a reasonable price, with the exception of land, and second-hand goods, which are unique.

.There can be four different ways in which contracts can be set aside. A contract may be deemed ‘void‘, ‘voidable‘, ‘unenforceable‘or ‘ineffective’. Voidness implies that a contract never came into existence. Voidability implies that one or both parties may declare a contract ineffective at their wish. Unenforceability implies that neither party may have recourse to a court for a remedy. Ineffectiveness implies that the contract terminates by order of a court where a public body has failed to satisfy public procurement law. To rescind is to set aside or unmake a contract.

  1. Fry v. Barnes (1953) 2 D.L.R. 817 (B.C.S.C)
  2. Hillas and Co. Ltd. v. Arcos Ltd. (1932) 147 LT 503
  3. Whitlock v. Brew (1968) 118 CLR 445
  4. Three Rivers Trading Co., Ltd. v. Gwinear & District Farmers, Ltd. (1967) 111 Sol. J. 831


Contract theory is the body of legal theory that addresses normative and conceptual questions in contract law. One of the most important questions asked in contract theory is why contracts are enforced. One prominent answer to this question focuses on the economic benefits of enforcing bargains. Another approach, associated with Charles Fried, maintains that the purpose of contract law is to enforce promises. This theory is developed in Fried’s book, Contract as Promise. Other approaches to contract theory are found in the writings of legal realists and critical legal studies theorists.

More generally, writers have propounded Marxist and feminist interpretations of contract. Attempts at overarching understandings of the purpose and nature of contract as a phenomenon have been made, notably ‘relational contract theory’ originally developed by U.S. contracts scholars Ian Roderick Macneil and Stewart Macaulay, building at least in part on the contract theory work of U.S. scholar Lon L. Fuller, while U.S. scholars have been at the forefront of developing economic theories of contract focussing on questions of transaction cost and so-called ‘efficient breach‘ theory.

Recently it has been accepted that there is a third category, restitutionary obligations, based on the unjust enrichment of the defendant at the plaintiff’s expense. Contractual liability, reflecting the constitutive function of contract, is generally for failing to make things better , liability in tort is generally for action  making things worse, and liability in restitution is for unjustly taking or retaining the benefit of the plaintiff’s money or work.


  1. Ewan McKendrick, Contract Law – Text, Cases and Materials (2005) Oxford University Press ISBN 0-19-927480-0
  2. P.S. Atiyah, The Rise and Fall of Freedom of Contract (1979) Clarendon Press ISBN 0-19-825342-7
  3. www.
  4. Randy E. Barnett, Contracts (2003) Aspen Publishers ISBN 0-7355-6535-2
  5. Scott Fruehwald, “Reciprocal Altruism as the Basis for Contract,” 47 University of Louisville Law Review 489 (2009)
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  11. Committee on the Penalty for Homicide, (1993) The Report of an Independent Inquiry into the Mandatory Life Sentence for Murder, Commissioned by the Prison Reform Trust, London: Prison Reform Trust.
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