My understanding is that strong coupling effects arise from instantons in the path integral.
But I sometimes read that monopoles (see the electric-magnetic duality) can allow one to calculate strong coupling effects. How do I reconcile this with my understanding that instantons are responsible for strong coupling effects?
I guess the answer is: Instantons mediate (in time) between configurations of different winding number. This can be thought of as the creation or destruction of monopoles, since monopoles carry winding number.
Therefore, in a QFT of monopoles, where monopoles can be created and destroyed, instantons will naturally be accounted for, providing the non-perturbative physics.