Abstract
Allen Buchanan and Daniel Brock, in a widely influential account, Deciding for Others (1990), advocate a sliding scale approach to the determination of whether a patient is competent to make a decision regarding his/her health care. An analysis of two critiques of their position (Beauchamp and Childress (1994), Wicclair (1991 a,b)) reveals a tacit presumption by all of these authors that the greater cognitive challenge often posed by high risk therapies constitutes grounds for an elevated standard of competence. This presumption cannot be consistently maintained in cases where the patient's decision involves experimental therapies. It implies either that informed consent can never take place in such situations, or, perhaps even more counter-intuitively, that a lower standard of competency should be used than when the patient is asked to choose only among standard therapies.