Entropy increases the energy content of the black hole, increasing both its mass and the size of its event horizon. Bekenstein’s argument? Whenever the entropy of a black hole increases, so does the area of its event horizon. In other words, the area of the event horizon of a black hole was not an analogy for entropy, it was a direct measure of its entropy. In Bekenstein’s view, this saved the universal applicability of the second law of thermodynamics.
