The Replaceability Argument - Killing Happy Animals: Explorations in Utilitarian Ethics - page 69

7 Conclusion
The Replaceabiliy Argument proposes a way of compensating the
welfare loss that is implied by the killing of animals that would other-
wise have had a happy future. The idea of the Replaceability Argument
is that the welfare loss due to the killing can be compensated by
bringing into existence a new animal, which would not otherwise
exist and which will be at least as happy as the killed one would have
been. I have proposed the following definition of the Replaceability
Argument:
Replaceability Argument: It is permissible to kill an animal, provided
that the following conditions are met:
(a) The future welfare of the animal would have been positive;
(b) The animal will be replaced, at or after death, by another animal,
whose lifetime welfare is at least as positive as the future welfare
of the killed animal would have been, and which would not
otherwise exist; and
(c) The killing does not have any unbalanced negative side effects
(such as fear or suffering for the animal or others).
As far as we can tell, there may be practices of animal husbandry which
grant animals sufficiently pleasant lives and which avoid any unbal-
anced negative side effects of the killing. Probably, those systems would
need to score better in terms of animal welfare than current systems of
animal-friendly animal husbandry. With the aid of the Replaceability
Argument, utilitarianism would be able to morally justify these prac-
tices. Therefore, utilitarianism's support of these practices of 'animal-
friendly animal husbandry' depends on the Replaceability Argument.
The Replaceability Argument seems to imply that all animals,
including humans, are replaceable. In order to avoid that implication,
Singer has proposed a way to limit the scope of the Replaceability
Argument to non-persons. For that purpose, Singer has adopted a
certain account of welfare, consisting of a desire-satisfaction account
in conjunction with the 'moral ledger' model. Only the unmodified
moral ledger model implies that persons are not replaceable. It also
implies, among other things, that all of us would be better off having
not lived and that welfare can never be positive. Those who want to
adhere to the Replaceability Argument might accept this implication
or else accept that all animals, including humans, are in principle
replaceable.