  We show that self-reference can be formalized in Basic logic by means of the
new connective @, called "entanglement". In fact, the property of
non-idempotence of the connective @ is a metatheorem, which states that a
self-entangled sentence loses its own identity. This prevents having
self-referential paradoxes in the corresponding metalanguage. In this context,
we introduce a generalized definition of self-reference, which is needed to
deal with the multiplicative connectives of substructural logics.
