By issuing an advance treatment directive, an autonomous person can formally express what kinds of treatment she wishes and does not wish to receive in case she becomes ill or injured and unable to autonomously decide about her treatment. While many jurisdictions and medical associations endorse them, advance treatment directives have also been criticized. According to an important criticism, when a person irreversibly loses her autonomy what she formerly autonomously desired ceases to be of importance in deciding about her treatment. (...) The medical ethical debate regarding different possible ways of solving the problem on which the criticism is based has grown exceedingly intricate. Instead of assessing the developments made in the debate so far, I present a thought experiment—built around a suicide case—which suggests that the problem is not as intractable as it has generally been deemed to be. (shrink)