  This paper explores the options available to the anti-realist to defend a
Quinean empirical under-determination thesis using examples of dualities. I
first explicate a version of the empirical under-determination thesis that can
be brought to bear on theories of contemporary physics. Then I identify a class
of examples of dualities that lead to empirical under-determination. But I
argue that the resulting under-determination is benign, and is not a threat to
a cautious scientific realism. Thus dualities are not new ammunition for the
anti-realist. The paper also shows how the number of possible interpretative
options about dualities that have been considered in the literature can be
reduced, and suggests a general approach to scientific realism that one may
take dualities to favour.
