Also known as: of sound mind · mental competence
Written by attorneys · grounded in primary & secondary sources — see below
Mental capacity sufficient to understand in a general way the nature and extent of one's property, the natural objects of one's bounty, and the disposition being made of that property, along with the ability to relate these elements into an orderly plan.
Sean Steele, an eighty-year-old dairy farmer, sat at his kitchen table and signed a typed will leaving his milking equipment to his adult son. Two adult witnesses of ordinary competence signed the document in his presence. After his death his other children challenged the will on capacity grounds. The court upheld the will because Sean possessed the required mental capacity at the moment of execution.
Sasha Stone, an adult patient with terminal illness, directed her physicians to remove life support after full discussion of her condition. The hospital sought court approval to continue treatment over her objection. The court recognized her right to refuse because she was an adult of sound mind capable of making informed medical decisions.
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Sydney Santos, a terminally ill adult, sought a physician's assistance to end her life under a state statute. State officials defended the criminal prohibition. The court analyzed whether the statute infringed a liberty interest in bodily integrity held by adults of sound mind.
Santiago Sanchez, trustee of a common trust fund, mailed notice of an accounting only to adult beneficiaries known to be of sound mind. Unknown or incapacitated beneficiaries received only newspaper publication. The court held that notice by publication satisfied due process for those whose identities or capacities were not reasonably ascertainable.
Selena Singh stood trial for murder after shooting her spouse during an argument. The prosecution requested an instruction that a person of sound mind is presumed to intend the natural consequences of her acts. The court rejected the instruction because it created an unconstitutional mandatory presumption shifting the burden on intent.
The testator must be capable of knowing the nature and extent of property, the natural objects of bounty, the nature of the testamentary act, and how these elements relate to form an orderly plan of disposition. The testator need only have the ability to know this information, not actual knowledge of every detail.
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Yes. A person who generally lacks capacity may execute a valid will during a lucid interval when the required understanding is present. Courts examine the testator's condition immediately before and after execution to assess capacity at the precise moment of signing.
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Yes. Each witness must be generally competent, which includes being an adult of sound mind capable of observing, recalling, and testifying about the execution. An interested witness who meets this standard may still validly attest the will.
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The doctrine states that every human being of adult years and sound mind has the right to determine what shall be done with his or her own body. This formulation recognizes a competent adult's liberty to refuse medical treatment.
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…in bodily integrity was phrased in a general way by then-Judge Cardozo when he said, "[e]very human being of adult years and sound mind has a right to determine what shall be done with his own body" in relation to his medical needs. The familiar examples of this right derive from the common law of battery and include the…