Study guide
14.1 Consent: Express, Implied & Capacity
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1 Introduction & FYLSE Examination Guide
1.1 FYLSE Exam Structure, Passing Standard & Administration 1.2 Study Method, Pacing & MBE-Style Technique
2 Contracts: Mutual Assent, Capacity & Contract Formation
2.1 The Offer & Objective Theory of Assent 2.2 Termination & Irrevocability of Offers 2.3 Acceptance & the Mailbox Rule 2.4 Mirror Image Rule & UCC 2-207 Battle of the Forms 2.5 Mistake in Contract Formation 2.6 Fraud, Duress, Undue Influence & Illegality 2.7 Capacity to Contract
3 Contracts: Consideration, Estoppel & Implied Obligations
3.1 Consideration & the Bargained-For Exchange 3.2 Past & Moral Consideration, Pre-Existing Duty & Modification 3.3 Promissory Estoppel & Detrimental Reliance 3.4 Implied-in-Fact Contracts & Quasi-Contract 3.5 Implied Covenant of Good Faith, Fair Dealing & Indefinite Terms
4 Contracts: Third-Party Beneficiaries, Assignment & Delegation
4.1 Third-Party Beneficiary Contracts 4.2 Assignment of Rights 4.3 Delegation of Duties
5 Contracts: Statute of Frauds, Parol Evidence & Interpretation
5.1 Statute of Frauds: Contracts Within the Statute 5.2 Satisfying the Statute: Writing, Signature & Exceptions 5.3 The Parol Evidence Rule 5.4 Contract Interpretation & Canons of Construction
6 Contracts: Performance, Conditions, UCC Warranties & Breach
6.1 Conditions: Express, Constructive & Excuse 6.2 Substantial Performance vs. Perfect Tender 6.3 Cure, Rejection, Revocation & Installment Contracts 6.4 UCC Article 2 Warranties & Risk of Loss 6.5 Anticipatory Repudiation & Insecurity
7 Contracts: Remedies, Discharge & Changed Circumstances
7.1 Expectation Damages & Their Limitations 7.2 Reliance, Restitution & Liquidated Damages 7.3 Specific Performance & Injunctive Relief 7.4 UCC Article 2 Buyer's and Seller's Remedies 7.5 Impossibility, Impracticability & Frustration of Purpose 7.6 Discharge by Agreement: Rescission, Novation & Accord and Satisfaction
8 Criminal Law: Principles of Criminal Liability & Mens Rea
8.1 Actus Reus, Voluntary Acts & Omissions 8.2 Criminal Causation & Intervening Causes 8.3 Common Law & Model Penal Code Mens Rea 8.4 Mistake of Fact, Mistake of Law & Concurrence
9 Criminal Law: Inchoate Offenses & Accomplice Liability
9.1 Criminal Attempt & Impossibility 9.2 Solicitation & the Merger Doctrine 9.3 Conspiracy & Merger Doctrine 9.4 Accomplice Liability: Actus Reus & Mens Rea 9.5 Scope of Accomplice Liability, Withdrawal & Parties to Crime
10 Criminal Law: Homicide & Crimes Against the Person
10.1 Common Law Murder & Malice Aforethought 10.2 Degrees of Murder, Premeditation & Deliberation 10.3 The Felony Murder Rule & Its Limitations 10.4 Voluntary & Involuntary Manslaughter 10.5 Non-Homicide Crimes Against the Person
11 Criminal Law: Property Crimes, Theft & Habitation
11.1 Common Law Larceny 11.2 Embezzlement & False Pretenses 11.3 Robbery & Extortion 11.4 Receiving Stolen Property 11.5 Burglary 11.6 Arson
12 Criminal Law: Defenses: Capacity, Justification & Excuse
12.1 Insanity: The Four Legal Tests 12.2 Intoxication, Diminished Capacity & Infancy 12.3 Self-Defense & Defense of Others 12.4 Defense of Property, Habitation & Law Enforcement Privileges 12.5 Duress & Necessity 12.6 Entrapment & Mistake as an Excuse
13 Torts: Intentional Torts to Persons & Property
13.1 Intent, Motive & Incapacity in Intentional Torts 13.2 Transferred Intent 13.3 Battery & Assault 13.4 False Imprisonment 13.5 Trespass to Land 13.6 Trespass to Chattels & Conversion
14 Torts: Privileges & Defenses to Intentional Torts
14.1 Consent: Express, Implied & Capacity 14.2 Exceeding & Vitiating Consent 14.3 Self-Defense & Defense of Others (Tort) 14.4 Defense of Property & Recapture of Chattels 14.5 Public & Private Necessity 14.6 The Shopkeeper's Privilege
15 Torts: Negligence — Duty of Care & Breach
15.1 Duty of Care & the Foreseeable Plaintiff 15.2 Affirmative Duties to Act & Special Relationships 15.3 Standard of Care: The Reasonable Person & Children 15.4 Professional Negligence, Informed Consent & Negligence Per Se 15.5 Land Possessor Liability & Premises Duties 15.6 Breach of Duty & Res Ipsa Loquitur
16 Torts: Causation, Defenses, Multiple Tortfeasors, Wrongful Death & Damages
16.1 Cause in Fact & Multiple Actors 16.2 Proximate Cause & Intervening Forces 16.3 Contributory, Comparative Negligence & Assumption of Risk 16.4 Joint and Several Liability, Contribution & Indemnity 16.5 Vicarious Liability & Non-Delegable Duties 16.6 Wrongful Death & Survival Actions 16.7 Statute of Limitations & Claim Accrual 16.8 Tort Damages: Compensatory, Nominal, Punitive & Mitigation
17 Torts: Strict Liability & Products Liability
17.1 Strict Liability for Animals 17.2 Abnormally Dangerous Activities & Scope of Risk 17.3 Strict Products Liability & Defect Categories 17.4 Products Liability Under Negligence, Warranty & Misrepresentation 17.5 Defenses to Products Liability
18 Torts: Emotional Distress, Defamation, Privacy & Economic Torts
18.1 Intentional Infliction of Emotional Distress 18.2 Negligent Infliction of Emotional Distress 18.3 Common Law Defamation: Elements, Libel & Slander 18.4 Constitutional Limits, Privileges & Defenses to Defamation 18.5 Invasion of Privacy 18.6 Nuisance & Economic Torts
14.1 Consent: Express, Implied & Capacity
Key Takeaways Explain This Topic AI
Consent is a complete defense to the intentional torts, and may be express or implied from the plaintiff's conduct and the surrounding custom.
Implied consent by custom covers ordinary contacts of daily life such as jostling in a crowd, and consent to the ordinary contacts of a contact sport.
Under the emergency doctrine, consent to medical treatment is implied where the patient is unable to consent, no one authorised is available, and a reasonable person would consent.
Persons lacking capacity through youth, intoxication, or mental incompetence cannot give effective consent to conduct they cannot appreciate.
The majority rule holds that consent to a criminal act is still effective as a defense, while a substantial minority treats it as ineffective.
Last updated: September 2026
Consent: Express, Implied & Capacity
Doctrinal Foundation: In the law of intentional torts, affirmative defenses and privileges concede that the defendant's conduct met the prima facie elements of an intentional invasion (such as an intentional physical contact in battery, a volitional boundary crossing in trespass to land, or an intentional restraint in false imprisonment), but assert that under the circumstances, the conduct was socially justified, legally excusable, or authorized by the plaintiff. The fundamental common-law defense is consent ( volenti non fit injuria —"to one who consents, no wrong is done"). On the California First-Year Law Students' Examination (FYLSE), examiners systematically test the line between express and implied consent, the boundaries of legal capacity, the strict anatomical limits on medical authorization ( Mohr v. Williams ), the critical division between fraud in the factum and fraud in the inducement, and the jurisdictional split regarding consent to illegal conduct.
I. Manifestations of Consent: Express vs. Implied
Consent operates as an absolute bar to recovery for any intentional invasion of person or property. The law recognizes that consent may be communicated explicitly through words or inferred from objective human conduct and societal custom. ┌──────────────────────────────────────┐
- │ Manifestations of Consent │
- └──────────────────┬───────────────────┘
- │
- ┌──────────────────┬────────────────┴──────────────────┬──────────────────┐
- ▼ ▼ ▼ ▼
- [EXPRESS CONSENT] [APPARENT (IMPLIED IN FACT)] [IMPLIED BY LAW] [EMERGENCY MEDICAL]
- Clear oral or - Objective outward conduct - Customary social - Unconscious patient
- written agreement and gestures touches & transit - Imminent lethal peril
- Explicit license - O'Brien v. Cunard S.S. Co. - Sports within - Reasonable person consents
- to enter or touch - Subjective reluctance immaterial customary rules - No known prior refusal
- 1. Express (Actual) Consent
Express consent exists where the plaintiff explicitly communicates a willingness to submit to the defendant's conduct through unequivocal oral statements or executed written documents. For example, an individual who executes a detailed surgical consent form authorizing a specific surgical procedure, or a homeowner who verbally invites a neighbor to enter a parcel of real property, has conferred express consent.
2. Apparent Consent (Implied in Fact)
Apparent consent arises when a reasonable person in the position of the defendant would believe, based on the plaintiff's objective conduct, overt physical gestures, and the surrounding circumstances, that the plaintiff consented to the invasion. The landmark authority is O'Brien v. Cunard S.S. Co. , 154 Mass. 272 (1891):
The O'Brien Doctrine: An immigrant passenger aboard a steamship stood in line with other passengers receiving mandatory smallpox vaccinations. When her turn arrived, she observed others receiving injections and silently held out her bare arm to the ship's surgeon. After receiving the vaccination, she sued the surgeon for battery, asserting that she inwardly objected to the procedure.
The Rule: The court held that consent is determined by outward, objective manifestations , not unexpressed, subjective mental reservations. Because a reasonable physician would interpret holding out an arm in a vaccination line as an overt manifestation of consent, apparent consent was established as a matter of law, completely barring the battery action.
3. Implied by Law: Custom & Everyday Social Usage
Civilized society necessitates countless incidental physical contacts that individuals are deemed to have consented to by virtue of participating in community life. Tapping a stranger on the shoulder to ask for the time, brushing against commuters in a crowded subway car or theater corridor, or shaking hands in a business greeting are privileged by implied consent under prevailing social customs.
4. Athletic Participation & Contact Sports
An athlete who voluntarily participates in a sport impliedly consents to physical contacts and collisions that are customary, recognized incidents of the game:
Customary Collisions Privileged: A football player impliedly consents to being tackled, blocked, and shoved within the ordinary flow of play.
Violations of Safety Rules Outside Play ( Hackbart v. Cincinnati Bengals , 601 F.2d 516 (10th Cir. 1979)): Implied consent in athletics is strictly limited to the rules and recognized customs of the sport . In Hackbart , an opposing football player, frustrated by a turnover, intentionally struck an opposing safety on the back of the neck with a forearm blow during a dead-ball play after the whistle had blown. The Tenth Circuit held that while football involves violent physical collision, players do not consent to intentional, malicious strikes delivered outside the boundaries of active play in flagrant violation of general safety rules. The blow constituted an actionable battery.
5. The Emergency Medical Exception
Where an individual is incapable of providing actual consent due to sudden trauma or illness, the law implies consent to prevent death or permanent bodily harm if four cumulative elements are satisfied:
Incapacity: The patient is unconscious, incompetent, delirious, or otherwise physically incapable of giving valid consent;
Imminent Peril: An immediate medical or surgical intervention is necessary to prevent death, loss of limb, or irreversible impairment of health;
Presumed Reasonable Assent: An ordinary, reasonable person in the patient's position would consent to the life-saving procedure under the circumstances; and
Absence of Known Objections: The attending medical providers have no reason to know that the patient, while competent, previously refused the procedure or harbored religious or personal objections (such as an executed advance healthcare directive or known Jehovah's Witness objection to blood transfusions).
II. Legal Capacity to Consent
Consent is legally ineffective if the plaintiff lacks the legal and cognitive capacity to understand the nature, quality, and consequences of the physical act. When legal capacity is absent, the defendant cannot invoke the plaintiff's apparent assent as a defense.
1. Infancy (Minors)
General Incapacity for Serious Invasions: Very young children conclusively lack legal capacity to consent to invasive medical procedures, sexual conduct, or substantial physical violence.
Age-Appropriate Peer Activities: An older child (such as a 12-year-old) possesses legal capacity to consent to normal, age-appropriate peer contacts, such as neighborhood playground games, touch football, or wrestling matches. However, an adolescent cannot consent to activities involving substantial bodily harm or statutory sexual offenses.
2. Intoxication
Alcohol or drug impairment invalidates consent only if two strict conditions are met:
The intoxication was so profound that the plaintiff was incapable of understanding the nature, quality, and consequences of the invasion; and
The defendant knew or reasonably should have known of the plaintiff's severely incapacitated state.
If an intoxicated individual appears outwardly lucid and comprehends the physical invasion, consent remains valid in tort, even if their inhibitions were significantly reduced.
3. Mental Incompetence
Individuals suffering from profound mental illness, intellectual disability, or neurological dementia lack the legal capacity to authorize intentional physical invasions if they cannot grasp the basic physical nature and significance of the touching.