Determining proxy consent

The paper clarifies the relative merits and proper roles of standards of review in the determination of proxy consent for those unable to make decisions concerning their own medical treatment. The "substituted judgment" standard asks which treatment the incompetent person would choose if competent, while the "best interests" test asks which treatment would benefit the patient. The tests are discussed in relation to the moral principles of autonomy and beneficence which provide their justification. I distinguish six types of cases involving incompetent patients and argue that which standard is appropriate depends on the type of case involved. A "rational choice" standard, which asks "What would the incompetent patient choose if his or her choice were rational?", is proposed as a way of determining best interests.