Medical ethics has traditionally been governed by two guiding, but sometimes conflicting, principles—autonomy and benevolence. These principles provide the rationale for the two most commonly used standards for medical decisionmaking—the Substituted Judgment Standard shows our concern for autonomy, whereas the Best Interest Standard shows our commitment to benevolence. Both standards are vulnerable to criticisms. Further, the principles can seem to offer conflicting prescriptions for action. The criticisms and conflict figure prominently in discussion of advance directive decisionmaking and Alzheimer's disease. After laying out each of the current standards and its problems, with Alzheimer's issues as my central concern, I offer a new standard that avoids the problems while honoring our concerns for both autonomy and benevolence.