 Self-doubting defeaters are about agents and they are in addition agent-specific (Christensen 2010a: 202). They are based on information about you, the person who came to the conclusion about that support relation, and have direct negative implications only for your conclusion. In the case of the cloth, anyone with the same evidence would have their justification undercut by the evidence of the red light. The evidence that the doctor is underslept, however, would not affect the justification possessed by some other doctor who had reasoned from the same evidence to the same conclusion using the same background knowledge. The evidence that the pilot is at risk of hypoxia would not be a reason for a person on the ground, who had reasoned from the same instrument readings to the same conclusion, to give up the belief that the plane had enough fuel for fifty more miles.