The Replaceability Argument - Killing Happy Animals: Explorations in Utilitarian Ethics - page 58

and non-humans, as this would be likely to be unjustified discrimina-
tion, and thus what Singer calls 'speciesist'. Instead, criteria are used that
follow directly from Singer's account of welfare: what matters is how
future-oriented a being is.
Before I will critically discuss Singer's account, I need to mention one
important revision that Singer has made to the moral ledger model. As
people have usually at least some unsatisfied preferences when they die,
the moral ledger model implies that all of us score negative on lifetime
welfare and thus that all of us would be better off having not lived.
In order to avoid this unwelcome implication, Singer has proposed the
following modification of the moral ledger model:
Thus the moral ledger model of creating and satisfying a preference
will not do. It might be saved by attaching to it a stipulation that sets
a given level of preference satisfaction, below complete satisfaction,
as a minimum for overcoming the negative entry opened by the crea-
tion of a being with unsatisfied preferences. This might be the level at
which we consider a life ceases to be worth living, from the perspec-
tive of the person leading that life. Such a solution seems a little ad
hoc, but it may be possible to incorporate it into a plausible version
of preference utilitarianism. 20
The idea is that a being's welfare level is negative as soon as a being has
unsatisfied preferences. It is immediately restored to a zero level if the
preference is satisfied. The welfare level remains negative as long as one
or more preferences remain unsatisfied. In order to avoid the implication
that most of us would be better off had we not lived, Singer claims at this
point that not all preferences need to be fulfilled in order to consider a
life worthwhile. So, a life in which some preferences are not fulfilled can
still come out of the negative score. The 'zero' is moved down the scale,
in order to transform minuses into zero. It seems that Singer wants to
say that the 'minus' will be erased and one will score 'zero', even if not
all preferences are fulfilled. Thus, the neutral situation does not require
the satisfaction of all preferences. This is probably in line with people's
experience of their welfare. Furthermore, it avoids the implication that
all of us would be better off having not lived. Most people will achieve
the zero level of welfare if one needs not to have all preferences fulfilled
in order to come out of the negatives.
While it is obvious that according to the moral ledger model welfare
could only be negative - or at best neutral - it is less clear how this
would be the case according to the modified moral ledger model.