Any of us could face the possibility at some time of standing at the bedside of a loved one who is in a comatose or vegetative state, without any hope of recovery and dependent on artificial life support. That such patients are no longer able to convey their wishes as to the health care they want, including any treatment to prolong life, can place a heavy burden on relatives.
Any one of us, too, could be the patient in the bed, dependent for our best interests on agreement between family and doctors as to whether life-prolonging measures should be continued, or whether they no longer serve any useful humane purpose, and may indeed cause unnecessary suffering.
This dilemma is as old as modern medicine. The ultimate arbiter of any moral and ethical conflict between the sanctity of life and compassion - for example the wishes of the family and the medical realities - is the law, which forbids euthanasia.
It can help everyone, including the law, if the patients' wishes are known - expressed in advance in the form of directions about health care if and when they no longer have the capacity to make decisions. In Hong Kong, however, even then the family may oppose these wishes. Nor is a doctor necessarily protected from legal action if he follows them, although he may appeal to higher authority.
The Law Reform Commission report issued yesterday on decisions about medical treatment for people who are comatose or in a vegetative state, or terminally ill, does not propose radical changes such as more legal protection for doctors treating them. It has still run into flak from both the medical profession and patients' rights groups, a reminder that the subject is ethically and culturally sensitive.
Nonetheless, any initiative that seeks to remove some of the uncertainties from a difficult situation for family and doctor is to be welcomed. The commission's report amounts to a proposal that patients can leave a kind of will giving a written directive in advance about the health care they want if they are one day incapable of making decisions.
The commission recommends a model form of directive at this stage rather than a version prescribed by legislation, to give the community time to come to terms with the concept.
People may already give such advance directions, which are recognised as valid if they are clear and untainted by the suggestion of incapacity or undue influence. But the lack of an agreed form in which they should be set out can present difficulties for both patient and doctor.
A standard form of directive is only a small step towards addressing fundamental issues of the right to live and the right to die with dignity.
But such a document might have made a big difference, for example, to the seven-year legal battle over the widely publicised case last year of the severely brain-damaged American woman, Terri Schiavo. In the end, a judge relied on her husband's testimony - not documentary evidence - that she had expressed a wish not to have treatment that would prolong life in a vegetative state, despite her parents' objections.
The commission recommends sensible safeguards, including appropriate witnesses to advance directives and a person's right to revoke them at any time. It believes that if the form is correctly completed, an individual can be reasonably assured that their wishes will be carried out.
The idea is an improvement for both doctors and patients that could also have educational value on an issue about which most people know little until they are confronted with it. But it is important to emphasise the voluntary nature of it. Any suggestion of compulsion or persuasion would give rise to moral and ethical concerns.
Since such directives might exist for many years during which personal circumstances may change, they may be more convincing evidence of a patient's wishes if they have to be reaffirmed from time to time.