  We show that perturbative quantum gravity based on the Einstein-Hilbert
action, has a novel continuum limit. The renormalized trajectory emanates from
the Gaussian fixed point along (marginally) relevant directions but enters the
diffeomorphism invariant subspace only well below a dynamically generated
scale. We show that for pure quantum gravity to second order in perturbation
theory, and with vanishing cosmological constant, the result is the same as
computed in the standard quantisation. Although this case is renormalizable at
second order for kinematic reasons, the structure we uncover works in general.
One possibility is that gravity has a genuine consistent continuum limit even
though it has an infinite number couplings. However we also suggest a possible
non-perturbative mechanism, based on the parabolic properties of these flow
equations, which would fix all higher order couplings in terms of Newton's
constant and the cosmological constant.
