Abstract
The emergence of classical properties in quantum gravity is discussed through the use of the decoherence functional. Because there is no external time parameters in quantum gravity, its formulation is different from the one in quantum mechanics. It is shown that the decoherence functional can be applied in the usual sense, if gravity can be approximated semiclassically. To illustrate the essential features, the model of a scalar field on de Sitter space is discussed in detail.