Jacob Bekenstein found... in 1971 that every black hole must have an entropy proportional to the area of its horizon... Stephen Hawking then refined this by showing that the constant of proportionality must be... exactly one quarter.... entropy is supposed to correspond to a measure of information... Loop quantum gravity... [gives] a detailed description of the microscopic structure of a black hole.... a horizon can have, for each quantized unit of area, a finite number of states. Counting them, we get exactly Bekenstein's result...

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)