 Some philosophers argue that dualist accounts of survival fail because we have no “criteria of identity” for disembodied persons. When we make judgments about the identity of persons we are not making judgments about the identity of souls. It has been argued that we cannot make judgments about the identity of souls, because souls are said to be imperceptible and non-spatial. And because of this, the identity of a person over time cannot consist of the identity of the person’s soul over time. What we are able to identify—and re-identify—is a person’s body. But once the person has died that body decomposes in a grave, and can’t be the basis for our identification of the person who is supposed to have survived disembodied (Perry 1978: 6–18).