  `Shallow' and `deep' versions of scientific realism may be distinguished as
follows: the shallow realist is satisfied with belief in the existence of the
posits of our best scientific theories; by contrast, deep realists claim that
realism can be legitimate only if such entities are described in metaphysical
terms. We argue that this methodological discussion can be fruitfully applied
in Everettian quantum mechanics, specifically on the debate concerning the
existence of worlds and the recent dispute between Everettian actualism and
quantum modal realism. After presenting what is involved in such dispute, we
point to a dilemma for realists: either we don't have the available
metaphysical tools to answer the deep realist's demands, and realism is not
justified in this case, or such demands of metaphysical dressing are not
mandatory for scientific realism, and deep versions of realism are not really
required.
