 It is fairly obvious that some individuals cannot make their own decisions: persons who are unconscious (temporarily or permanently), individuals with severe brain damage, infants and very small children, those who are born with severe cognitive impairment, and those in the advanced stages of dementia. We do these individuals no favor by pretending that they can decide for themselves. Instead, we must try to look out for these vulnerable individuals in our midst, and to the extent possible, ensure that their perspectives are taken into account in making decisions for them (Silvers &amp; Francis 2009). But these are the “easy” cases. The more difficult task is to develop a fair and consistent notion of decisional capacity that applies to the more subtle cases, the ones in which individuals have some but not all of the mental capacities of ordinary adult agents. It is a moral failure if we say of someone who lacks decisional capacity that she has it, for then we fail to protect someone who genuinely cannot decide for herself. But it is also a serious moral failure to say of someone who has decisional capacity that she lacks it, for we then deprive someone of a very important moral power: the power to direct her own life through making her own decisions (Buchanan &amp; Brock 1989: 40–41; Kim 2010: 1). Those who tackle the issue of capacity face moral danger of various types, and there is no easy way to avoid all moral pitfalls all the time.