Why Decision-making Capacity Matters

Decision-making Capacity (DMC) matters to whether a patient's decision should determine her treatment. But why it matters in this way isn't clear. The standard story is that DMC matters because autonomy matters. And this is thought to justify DMC as a gatekeeper for autonomy - whereby autonomy concerns arise if but only if a patient has DMC. But appeals to autonomy invoke two distinct concerns: concern for authenticity - concern that a choice is consistent with an individual's commitments; and concern for sovereignty - concern that an individual exercises control over that which is hers to control. Here, I argue, neither concern can alone explain why DMC matters. Instead, DMC matters because it indicates a harmony between the two concerns - the demands of each concern are more likely to agree if a patient has DMC. This vindicates the standard story, but also makes clear that DMC is an inappropriate gatekeeper for autonomy.