Was Samson a moron, or does beguiling actually work?

[Jenny A]

I recently finished this book that had some info on Samson:
http://books.google.com/books/about/From...UZO_vj-8IC

The authors believe that in the original myth, Samson was the offspring of a human mother and a heavenly being (similar to the nephilim in Genesis). Some of the Jewish literature describes Samson as an enormous giant who was able to carry the gates of a city on is shoulders, etc.

What evidence do the authors use to reconstruct the original myth?