To move from abstract ethical theories (like Mill or Aquinas) to the hard legal reality in the UK and Ireland. Students must understand that "wanting to die" is not enough; one must be legally "competent" to make that choice.
1. The Statutory Definition (Mental Capacity Act 2005)
Explain that in England and Wales, capacity is not a "yes/no" switch for a person’s whole life. It is decision-specific and time-specific.
The 4-Step Test: Walk students through the requirements:
Understand: Can they grasp the medical facts?
Retain: Can they remember the info long enough to decide?
Weigh: Can they balance the "benefit" of death vs. the "loss" of life?
Communicate: Can they signal their choice (speech, sign, or blinking)?
The "Presumption of Capacity": Crucial point—the law assumes you have capacity unless proven otherwise. However, in euthanasia cases, the burden of proof is incredibly high.
2. The "Fluctuating Capacity" Problem
In the early stages of dementia, a patient might have "good days" and "bad days."
The Legal Conflict: If a patient signs a request on a "good day," is it still valid on a "bad day"?
Teacher Tip: Ask the students: "If someone changes their mind during a moment of confusion, which version of the person should the doctor listen to? The 'clear' version from yesterday, or the 'confused' version of today?"
3. Depression vs. Rationality
A major hurdle in the UK is the link between terminal illness and clinical depression.
The Argument: Opponents argue that a request for death is often a symptom of depression (which impairs capacity) rather than a rational choice.
Counter-point: Proponents argue that being sad about dying is a "rational response," not a mental illness that should strip you of your rights.
Critical Vocabulary for the Classroom:
Competence: The legal standard of being able to make a specific decision.
Functional Test: The method used to see if someone can understand, retain, and weigh information.
Best Interests: If capacity is lost, the UK law switches to what is in the patient's "Best Interests." (Currently, the UK courts decided in the Tony Bland case that death is almost never in a person's "best interest" if they can't ask for it).