Contract Formation: Nature, Classification & Agreement — A Common Law Guide
The Business Law Playbook Series — Contracts and E-Contracts — Playbook 1
Summary: Playbook 1 examines the formation of contracts under common law, covering the nature and classification of contracts, the elements of a valid contract, bilateral and unilateral contracts, express and implied contracts, quasi-contracts, and the critical process of offer and acceptance — including termination of offers, the mailbox rule, the battle of the forms, and defective agreements. Detailed case law analysis is provided for all key principles.
Chapter 1 — Nature and Classification of Contracts
1.1 Definition and Elements of a Contract
A contract is a legally enforceable agreement between two or more parties that creates obligations which are enforceable by law. The common law requires four essential elements for a valid contract: agreement (offer and acceptance), consideration, contractual capacity, and legality. The Restatement (Second) of Contracts defines a contract as "a promise or set of promises for the breach of which the law gives a remedy, or the performance of which the law in some way recognizes as a duty."
The essential elements of a contract under common law:
- Offer: A clear, definite proposal to enter into an agreement, showing an intention to be bound upon acceptance and including specific terms
- Acceptance: An unambiguous manifestation of assent to the terms of the offer, which must mirror the offer's terms
- Consideration: Something of value exchanged between the parties, representing the bargained-for exchange
- Contractual Capacity: The legal ability of the parties to enter into a binding agreement
- Legality: The purpose of the contract must be lawful and not contrary to public policy
Under common law, the plaintiff bears the burden of proving each of these elements on the balance of probabilities. The law adopts a broadly objective test as to contract formation. Merely because one party mistakenly believes some fact of the contract to be other than it is, this will not invalidate the existence of a contract, unless this mistake was so obvious as to be objectively apparent.
In Smith v Hughes (1871) LR 6 QB 597, the defendant buyer believed he was purchasing old oats, while the seller knew they were new oats. The defendant refused to accept delivery when he discovered the mistake. The court held that the contract was valid because the buyer had not made the age of the oats a condition of the contract. Cockburn CJ stated that the argument that the parties were not ad idem "proceeds on the fallacy of confounding what was merely a motive operating on the buyer to induce him to buy with one of the essential conditions of the contract." The parties were "agreed as to the sale and purchase of this particular parcel of oats." The court established that if a party intends to contract on specific terms, they must ensure those terms become part of the contract. The "mere abstinence from disabusing the purchaser of that impression is not fraud or deceit, for, whatever may be the case in a court of morals, there is no legal obligation on the vendor to inform the purchaser that he is under a mistake which has not been induced by the act of the vendor."
This case established the objective principle of contract formation: a party is bound by their outward conduct, not their subjective intentions. Blackburn J stated that "if, whatever a man's real intention may be, he so conducts himself that a reasonable man would believe that he was assenting to the terms proposed by the other party, and that other party upon that belief enters into the contract with him, the man thus conducting himself would be equally bound as if he had intended to agree to the other party's terms."
1.2 Bilateral vs. Unilateral Contracts
Contracts are classified by the nature of the promises exchanged:
Bilateral Contract — A contract in which both parties exchange promises. Each party is both a promisor and a promisee. The contract is formed at the moment the promises are exchanged, before any performance occurs.
Unilateral Contract — A contract in which one party makes a promise in exchange for the other party's performance. The offeror promises to pay upon completion of the act, and the offeree accepts by performing. In a unilateral contract, the offer is accepted by performance rather than by a return promise.
The landmark case of Carlill v Carbolic Smoke Ball Co [1893] 1 QB 256 established the principles of unilateral contracts. The defendant company advertised that it would pay £100 to anyone who used their smoke ball as directed and contracted influenza. The company deposited £1,000 with a bank to demonstrate its sincerity. Elizabeth Carlill purchased and used the smoke ball, caught influenza, and claimed the reward. The company refused payment, arguing there was no contract.
Held: The Court of Appeal found for Mrs Carlill. The court established several key principles:
- Offer to the world: An advertisement can constitute an offer to the public, not merely an invitation to treat. The company had indicated its seriousness by depositing £1,000 with the bank.
- Acceptance by performance: In a unilateral contract, acceptance occurs through performance of the condition (using the smoke ball). Notification of acceptance is not required where the offeror waives it. As Bowen LJ stated: "If I advertise to the world that my dog is lost, and that anybody who brings the dog to a particular place will be paid some money, are all the police or other persons whose business it is to find lost dogs to be expected to sit down and write me a note saying that they have accepted my proposal? ... the performance of the condition is sufficient acceptance without the notification of it."
- Consideration: The inconvenience suffered by the offeree in using the smoke ball constituted sufficient consideration. The company also derived a benefit from increased sales. The court stated that "inconvenience sustained by one party at the request of the other is enough to create a consideration." The court rejected the argument that there was no consideration because the company merely benefited from the sale, noting that the "use of the smoke ball was contemplated by the defendants as being indirectly a benefit to them, because the use of the smoke balls would promote their sale."
- Certainty of terms: The terms were sufficiently certain because a reasonable time for protection could be determined from the nature of the product and medical evidence.
1.3 Express vs. Implied Contracts
Contracts may be classified by how they are formed:
Express Contract — Formed through written or spoken words that clearly state the terms of the agreement. The parties' intentions are explicitly stated, leaving no ambiguity about the terms.
Implied Contract — Formed through conduct rather than explicit words. An implied-in-fact contract arises when the parties' conduct indicates an agreement. Courts infer the existence of a contract from the circumstances and the parties' behavior.
Implied Terms — Courts may imply terms into a contract in four categories:
- Implied by fact: Terms that courts assume both parties would have intended to include had they thought about the issue
- Implied by law: Terms imported by operation of law (e.g., in a contract for the sale of goods, an implied term that goods will be of satisfactory quality)
- Implied by custom: Terms based on local custom or usage
- Implied by trade usage: Terms commonly used in contracts within a particular trade
In Carlill v Carbolic Smoke Ball Co [1893] 1 QB 256, the court recognized that an offer made to the public in an advertisement constitutes an offer that can be accepted by performance, even without explicit communication of acceptance. This reflects the principle that contracts can be formed through conduct.
1.4 Quasi-Contracts and Quantum Meruit
Quasi-contracts (also known as implied-in-law contracts) are not actual contracts but are imposed by law to prevent unjust enrichment. The doctrine of quantum meruit ("as much as he deserves") allows recovery for the value of services rendered when no express contract exists.
The principle was established in Fibrosa Spolka Akcyjna v Fairbairn Lawson Combe Barbour Ltd [1943] AC 32. Fibrosa, a Polish company, contracted with Fairbairn to purchase machinery. Fibrosa paid a deposit in advance. The outbreak of World War II frustrated the contract, and Fairbairn retained the deposit. Fibrosa sought restitution of the money paid.
Held: The House of Lords held that Fibrosa was entitled to restitution of the deposit on the ground of total failure of consideration. Lord Wright established that the basis of quasi-contractual recovery is unjust enrichment. Where one party has been unjustly enriched at the expense of another, the law may impose an obligation to make restitution.
Lord Wright noted that the principle was based on the Roman law condictio causa data causa non secuta — recovery of money paid when the purpose for which it was paid has failed. The case established the modern principle that restitution is available where there has been a total failure of consideration, regardless of whether the contract was frustrated. The decision was followed in New Zealand (Bray v. Anderson [1956] NZLR 347) and accepted in Canada as a correct statement of the common law.
1.5 Executed vs. Executory Contracts
Contracts may be classified by their stage of performance:
Executed Contract — A contract in which all parties have fully performed their obligations. The contract is complete and no further performance is required.
Executory Contract — A contract in which some or all performance remains outstanding. One or both parties have yet to fulfill their obligations.
The classification affects the availability of certain remedies and the application of the Statute of Frauds. An executed contract is generally more difficult to rescind than an executory contract.
1.6 Valid, Voidable, Void, and Unenforceable Contracts
Contracts are classified by their legal effect and enforceability:
- Valid Contract: A contract that meets all the essential elements and is legally binding and enforceable.
- Voidable Contract: A contract that one party can avoid due to lack of capacity, duress, fraud, or misrepresentation. The contract remains valid until the party with the right to avoid exercises that right.
- Void Contract: A contract that has no legal effect from the beginning. It lacks at least one essential element and cannot be enforced by either party.
- Unenforceable Contract: A valid contract that cannot be enforced due to a legal defense, such as the Statute of Frauds or the expiration of the statute of limitations.
In Smith v Hughes, the court distinguished between a mere motive (the buyer's belief about the oats) and an essential condition of the contract. The buyer's failure to make the condition part of the contract meant he was bound. This illustrates the importance of ensuring that all terms are properly incorporated into the contract.
1.7 Applicable Law: Common Law vs. UCC
The applicable law depends on the subject matter of the contract:
Common Law — Governs contracts for services, employment, real estate, and intangible rights. The common law tradition "is simply the accumulation of judicial precedent based on the inherent power of the courts to declare law where no statute or constitutional provision controls."
Uniform Commercial Code (UCC) — Governs contracts for the sale of goods (tangible personal property). Article 2 of the UCC applies to transactions involving the sale of goods, with different rules for formation, modification, and enforcement.
The distinction is crucial because the rules differ significantly. For example, under the UCC, consideration is not required for modifications, and the Statute of Frauds requires a writing for the sale of goods over $500.
Chapter 2 — Agreement: Offer and Acceptance
2.1 The Offer (Intent, Terms, Communication)
An offer is a statement by one party (the offeror) of a willingness to enter into a contract on stated terms and be bound by them if those terms are accepted by the other party (the offeree). In common law, an "objective" approach is adopted to ascertain whether an offer has been made.
Key requirements of a valid offer:
- Intent to be bound: The offeror must intend to enter into a binding contract
- Definite terms: The offer must contain specific, clear terms
- Communication: The offer must be communicated to the offeree
The common law distinguishes between an offer and an invitation to treat. An invitation to treat is an invitation to others to make offers, not an offer itself. The case of Carlill v Carbolic Smoke Ball Co [1893] 1 QB 256 established that an advertisement can constitute an offer to the public if it indicates a willingness to be bound upon performance of specified conditions, particularly where the offeror has demonstrated seriousness (e.g., by depositing money in a bank).
In Smith v Hughes, the court held that the seller had not made a misrepresentation; the buyer simply had a mistaken belief about the quality of the oats. The offer was for the sale of a particular parcel of oats, and the buyer's subjective belief about the age of the oats did not affect the existence of the contract.
2.2 Termination of Offers (Revocation, Rejection, Counteroffer, Lapse)
An offer terminates under the following circumstances:
- Revocation: The offeror withdraws the offer before acceptance. Revocation must be communicated to the offeree and is effective when received.
- Rejection: The offeree declines the offer. Rejection terminates the offer and prevents later acceptance.
- Counteroffer: The offeree responds with changes to the terms. A counteroffer constitutes a rejection and a new offer.
- Lapse of Time: The offer expires after a reasonable time or after any time specified by the offeror.
- Death or Incapacity: The offer terminates if either party dies or becomes incapacitated before acceptance.
2.3 The Acceptance (Mirror Image Rule, Mailbox Rule)
Acceptance is the manifestation of assent to the terms of the offer. Under common law, acceptance must be unambiguous and communicated to the offeror.
The Mirror Image Rule — Acceptance must exactly match the terms of the offer. Any variation constitutes a counteroffer, not an acceptance. The rule ensures that the parties have reached a true meeting of the minds.
The Mailbox Rule — Under the mailbox rule (also known as the postal acceptance rule), acceptance is effective upon dispatch rather than upon receipt by the offeror.
In Adams v Lindsell (1818) 1 B & Ald 681, the defendants posted an offer for the sale of wool to the plaintiffs, but misdirected the letter, causing a delay in delivery. The plaintiffs posted an acceptance, but by the time it was received, the defendants had already sold the wool to a third party.
Held: The Court of King's Bench held that the contract was formed at the moment of posting the acceptance. Lord Ellenborough stated that "if that were so, no contract could ever be completed by the post. For if the defendants were not bound by their offer when accepted by the plaintiffs till the answer was received, then the plaintiffs ought not to be bound till after they had received the notification that the defendants had received their answer and assented to it. And so it might go on ad infinitum."
The court established two key principles:
- Postal rule: Acceptance is complete upon posting, not upon receipt.
- Risk of delay: The offeror bears the risk of delay or loss in the post, provided the acceptance is properly addressed and stamped.
The court reasoned that "the defendants must be considered in law as making, during every instant of the time their letter was travelling, the same identical offer to the plaintiffs; and then the contract is completed by the acceptance of it by the latter." The rule has been applied to other non-instantaneous methods of communication, but for instantaneous communications (telephone, email), acceptance is effective upon receipt.
2.4 The Uniform Electronic Transactions Act (UETA)
The Uniform Electronic Transactions Act (UETA) provides a uniform legal framework for electronic transactions and signatures. It establishes that electronic records and signatures have the same legal effect as paper documents.
The UETA applies to transactions where the parties have agreed to conduct business electronically. Key provisions include:
- Electronic records and signatures are not denied legal effect solely because they are in electronic form
- Electronic signatures are attributable to the person to whom they are attributed
- Electronic records are considered to be sent and received when they are transmitted
The UETA has been adopted by most states and provides a framework for the growing use of electronic contracts and digital signatures in commercial transactions.
2.5 E-Contracts and Electronic Signatures (ESIGN Act)
The Electronic Signatures in Global and National Commerce Act (ESIGN Act) provides that electronic signatures are legally binding and that contracts cannot be denied enforceability solely because they are in electronic form.
Key provisions of the ESIGN Act include:
- Electronic signatures have the same legal effect as handwritten signatures
- Contracts cannot be denied enforceability solely because they are in electronic form
- The Act applies to transactions in or affecting interstate or foreign commerce
- Consumer consent is required for electronic records
The ESIGN Act preempts inconsistent state laws and provides a national standard for electronic commerce.
2.6 Battle of the Forms (UCC 2-207)
The "battle of the forms" occurs when parties exchange conflicting standard forms, each containing terms that conflict with the other. In common law, the mirror image rule would treat any variation as a counteroffer.
Under UCC 2-207, additional or different terms in an acceptance become part of the contract unless:
- The offer expressly limits acceptance to the terms of the offer
- The additional terms materially alter the contract
- The offeror objects to the additional terms within a reasonable time
The "battle of the forms" is a contentious issue, with courts and scholars debating how to resolve contract formation when parties exchange conflicting forms. The UCC approach represents a significant departure from the common law mirror image rule.
2.7 Defective Agreements (Fraud, Misrepresentation)
An agreement may be defective if it involves fraud or misrepresentation, which affects the reality of consent.
Fraudulent Misrepresentation — Occurs when one party makes a false representation of material fact with the intent to induce reliance. The elements of fraudulent misrepresentation include:
- False representation of material fact
- Scienter (knowledge of falsity or reckless disregard)
- Intent to induce reliance
- Justifiable reliance
- Causation of damages
In Smith v Hughes, the court distinguished between a mere failure to disclose a material fact and active misrepresentation. Blackburn J stated that "a mere abstinence from disabusing the purchaser of that impression is not fraud or deceit, for, whatever may be the case in a court of morals, there is no legal obligation on the vendor to inform the purchaser that he is under a mistake which has not been induced by the act of the vendor." This established that silence does not constitute fraud unless there is a duty to disclose.
Under common law, misrepresentation can be fraudulent (intentional), negligent, or innocent. Fraud in the inducement occurs when a party is induced to enter a contract by fraudulent statements, making the contract voidable. Fraud in the factum occurs when the very nature of the contract is misrepresented, rendering the contract void.
FAQ
What is the objective test in contract formation?
The objective test determines whether a contract has been formed based on how a reasonable person would interpret the parties' words and conduct. In Smith v Hughes, Blackburn J stated: "If, whatever a man's real intention may be, he so conducts himself that a reasonable man would believe that he was assenting to the terms proposed by the other party, and that other party upon that belief enters into the contract with him, the man thus conducting himself would be equally bound as if he had intended to agree to the other party's terms."
What is the mailbox rule in contract law?
The mailbox rule (postal acceptance rule) provides that acceptance of an offer is effective upon dispatch (posting) rather than upon receipt by the offeror. This rule was established in Adams v Lindsell (1818), where the court held that acceptance is complete upon posting. The rule applies to acceptances communicated by mail, provided the acceptance is properly addressed and stamped. The risk of delay or loss in the post falls on the offeror.
What is the difference between a bilateral and unilateral contract?
A bilateral contract is one in which both parties exchange promises. A unilateral contract is one in which one party makes a promise in exchange for the other party's performance, and acceptance occurs through performance rather than a return promise. Carlill v Carbolic Smoke Ball Co [1893] 1 QB 256 established that an advertisement can constitute a unilateral offer accepted by performance.
What is the "battle of the forms"?
The "battle of the forms" occurs when parties exchange conflicting standard forms, each containing terms that conflict with the other. Under common law, any variation constitutes a counteroffer. However, under UCC 2-207, additional terms in an acceptance become part of the contract unless they materially alter the contract or are objected to.
References
Forming a Contract - Common Law - Open Casebooks
Smith v Hughes (1871) LR 6 QB 597 - Open Casebooks
Carlill v Carbolic Smoke Ball Company [1892] EWCA Civ 1 - CommonLII
Adams v Lindsell (1818) 106 ER 250 - Open Casebooks
Fibrosa Spolka Akcyjna v Fairbairn Lawson Combe Barbour Ltd [1942] UKHL 4 - AustLII