Is the luminosity distribution of field galaxies really flat?

Recent observations of the galaxy population within rich clusters have found a characteristic luminosity distribution described by a flat (α = -1.0) Schechter function which exhibits an upturn at faint absolute magnitudes (M_B ≈ -18). Here we discuss whether such a form for the field luminosity distribution is ruled out by local and/or faint magnitude-limited redshift surveys (MLRSs). Our conclusions are that existing redshift surveys provide few constraints on the volume-density distribution of field galaxies faintward of M_B = -18. The local MLRSs suffer from poor statistics over inhomogeneous volumes, while the faint MLRSs are ambiguous because of the unknown nature of the "faint blue excess" and the "normalization" problem. Adopting a functional form similar to that seen in rich clusters we find that the maximum allowable faint end slope, based on the Mount Stromlo-APM redshift survey, is α ≈ -1.8 faintward of M_B = -18.0 (H₀ = 50 km s^-1 Mpc^-3).