  We evaluate the two pion exchange contribution to the nucleon-nucleon
potential in configuration space using a "minimal chiral model" containing only
pions and nucleons. We argue that this model has nowadays a rather firm
conceptual basis, which entitles it to become a standard ingredient of any
modern potential. The main features of this model is that the scalar-isoscalar
component of the interaction is relatively small, due to cancellations between
large terms, and fails to reproduce the intermediate range attraction in the
central channel. We show that chiral symmetry is the responsible for these
large cancellations in the two-pion exchange nucleon-nucleon interaction, which
are similar to those occuring in free pion-nucleon scattering. Another feature
of the model is that these results do not depend on how chiral symmetry is
implemented.
