  Suppose some future technology enables the same consciously experienced human
life to be repeated, identically or nearly so, N times, in series or in
parallel. Is this roughly N times as valuable as enabling the same life once,
because each life has value and values are additive? Or is it of roughly equal
value as enabling the life once, because only one life is enabled, albeit in a
physically unusual way? Does it matter whether the lives are contemporaneous or
successive? We argue that these questions highlight a hitherto neglected facet
of population ethics that may become relevant in the not necessarily far
distant future.
