In the first part of this article, I argue that even those entities
that in their own right and for their own sake give us reason not to
destroy them and to help them are sometimes substitutable for the good of
other entities. In so arguing, I consider the idea of being valuable as an
end in virtue of intrinsic and extrinsic properties. I also conclude that
entities that have claims to things and against others are especially
nonsubstitutable. In the second part, I argue that cloning poses no threat
to the nonsubstitutability of these entities (and in this sense, to the
dignity of persons). I also consider the relation between cloning and
(what I called) holistic identity, and between the latter and genetic
identity. In the concluding part of the article, I try to distinguish
cases where identity over time and so-called person-affecting acts have
and do not have greater moral significance than nonidentity over time and
nonperson-affecting acts. I try to apply my results to cases involving
embryos, future generations, and to the so-called Non-Identity
Problem.