The possible role of event-horizons in Quantum gravity

In this paper we extend to the de Sitter universe Bekenstein's result for the minimum variation of the black hole event-horizon area due to the absorption of an extended (classical) particle. Based on these equations we argue that at macroscopic scales the classical and quantum results should be in correspondence with each other (correspondence principle) and conclude that the event-horizon area is quantized in units of Planck's length squared. Consequences are discussed.