  We argue that the brane-world picture with matter-fields confined to 4-d
domain walls and with gravitational interactions across the bulk disallows
adding an arbitrary constant to the low-energy, 4-d effective theory -- which
finesses the usual cosmological constant problem. The analysis also points to
difficulties in stabilizing moduli fields; as an alternative, we suggest
scenarios in which the moduli motion is heavily damped by various cosmological
mechanisms and varying ultra-slowly with time.
