  The Tb$_2$Ti$_2$O$_7$ pyrochlore magnetic material is attracting much
attention for its {\em spin liquid} state, failing to develop long range order
down to 50 mK despite a Curie-Weiss temperature $\theta_{\rm CW} \sim -14$ K.
In this paper we reinvestigate the theoretical description of this material by
considering a quantum model of independent tetrahedra to describe its low
temperature properties. The naturally-tuned proximity of this system near a
N\'eel to spin ice phase boundary allows for a resurgence of quantum
fluctuation effects that lead to an important renormalization of its effective
low energy spin Hamiltonian. As a result, Tb$_2$Ti$_2$O$_7$ is argued to be a
{\em quantum spin ice}. We put forward an experimental test of this proposal
using neutron scattering on a single crystal.
