"To say that a life is grievable is to claim that a life, even before it is lost, is, or will be, worthy of being grieved on the occasion of its loss; the life has value in relation to mortality. One treats a person differently if one brings the sense of the grievability of the other to one’s ethical bearing toward the other. If an other’s loss would register as a loss, would be marked and mourned, and if the prospect of loss is feared, and precautions are thus taken to safeguard that life from harm or destruction, then our very ability to value and safeguard a life depends upon an ongoing sense of its grievability—the conjectured future of a life as an indefinite potential that would be mourned were it cut short or lost."