Why Did Paul Convert? Did He Convert?

The New Testament describes Paul's experience on several occasions: but can the accounts be trusted? Are they even consistent with each other? If we want to understand such a world-shattering experience, do we need to invoke the supernatural? Are there other plausible explanations? And is it right to call the event a "conversion" in the sense that Paul turned from one religion (Judaism) to another (Christianity)? These are all key issues for understanding a pivotal point in early Christian history, one that eventually would have enormous ramifications for the history of the west.