Smooth energy: Cosmological constant or quintessence?

For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as a function of the present ratio of smooth energy to matter energy, R-o. Identifying the normalized collapsed fraction as a conditional probability for habitable galaxies, we observe that the observed present ratio R-o similar to 2 is likely in LCDM, but more likely in QCDM. Inverse application of Bayes's theorem makes the anthropic principle a predictive scientific principle : the data imply that the prior probability for R-o must be essentially flat over the anthropically allowed range. Interpreting this prior as a distribution over theories lets us predict that any future theory of initial conditions must be indifferent to R-o. This application of the anthropic principle does not demand the existence of other universes.