These differences emerge clearly when we consider how
competing theories answer two distinct but related questions.
The first asks, What are the grounds for morally
limiting human freedom when it comes to human interactions
with nonhuman animals? The second asks, How
extensive are these moral limits on human freedom? The
former inquires as to why human freedom should be limited
at all when our actions affect other animals; the latter
challenges us to investigate how much our freedom should
be limited. Of the two questions, the first is the more basic,
for the reasons given in support of views about how much
our freedom should be limited ultimately are based on views
about why our freedom should be limited in the first place.
Two opposed possibilities present themselves as answers
to the first, more basic question. One possibility holds
that it is because of how animals themselves are affected or
treated by human agents that we should limit our freedom.
Viewed from this perspective, nonhuman animals are entitled
to a certain kind of consideration or treatment. Because
such views stress the idea that something is owed or is due
directly to these animals, it is common to refer to them as
“direct duty” views.