justifiably think of autonomous minisuperspace evolution only when this dissipation is small. Since we have used the scalar field modes to simulate higher gravitational modes these considerations can also be directly extended to include gravitons. [^7]

This is an example of how ideas of open systems can be useful in understanding dissipation and backreaction, even in quantum cosmology. One can also use this paradigm to address the problem of quantum to classical transition, specifically the relation of semiclassical gravity with quantum gravity, which we will now address. To do this the formalism will need to be elevated to the level of density matrices.

Semiclassical Limit of Quantum Cosmology
========================================

We now report on the result of some recent work by two of us (Paz and Sinha 1991, 1992) on this problem. Quantum cosmology rests on the rather bold hypothesis that the entire universe can be described quantum mechanically. This pushes us to question the usual Copenhagen interpretational scheme that relies on the existence of an [*a priori*]{} classical external observer/apparatus. Since in the case of quantum cosmology this cannot be assumed, the theory needs to predict the “emergence" of a quasiclassical domain starting from a fundamentally quantum mechanical description. Recently, 