When ideas collide, arguments ensue. When those who disagree want to take their disagreement public, and to compete with each other in front of an audience, a formal debate is held. This is a good way to quickly learn the finer points of each side of the disagreement.
Calvinism is a system of Christian thought known for a specific view of the predestination of believers. Molinism is a lesser-known system with a different view. If you've ever wondered about soteriology - that is, the doctrine of salvation - this podcast might be helpful to you.