  We make the cosmological constant, {\Lambda}, into a field and restrict the
variations of the action with respect to it by causality. This creates an
additional Einstein constraint equation. It restricts the solutions of the
standard Einstein equations and is the requirement that the cosmological wave
function possess a classical limit. When applied to the Friedmann metric it
requires that the cosmological constant measured today, t_{U}, be {\Lambda} ~
t_{U}^(-2) ~ 10^(-122), as observed. This is the classical value of {\Lambda}
that dominates the wave function of the universe. Our new field equation
determines {\Lambda} in terms of other astronomically measurable quantities.
Specifically, it predicts that the spatial curvature parameter of the universe
is {\Omega}_{k0} \equiv -k/a_(0)^(2)H^2= -0.0055, which will be tested by
Planck Satellite data. Our theory also creates a new picture of self-consistent
quantum cosmological history.
