For the two-charge extremal holes in string theory we show that the Bekenstein entropy obtained from the area of the stretched horizon has a statistical interpretation as a “coarse graining entropy”: different microstates give geometries that differ near r=0, and the stretched horizon cuts off the metric at r=b where these geometries start to differ.

• Received 12 February 2002

DOI:https://doi.org/10.1103/PhysRevLett.88.211303