Paul's 500 witnesses.

[Jehanne]

You might want try reading Catholic scholars, such as the late Father Raymond Brown, Father John Meier, etc.  In fact, you'll find a lot of believing scholars, both Protestant and Catholic, who do not take the "500" at face value.  You can start here for some critical (yet, believing) scholarship:

http://www.usccb.org/bible/1corinthians/15

OK, what part of that page says that the 500 is not to be taken at face value?

It doesn't, and I never claimed that it did, only that you'll find "critical scholarship" (yet, "believing scholarship") at that site.  Still, I can assure you that there are a number of Catholic and Protestant scholars, as well as secular ones, who do not believe the "500" to be historical, and yet, some still believe in the Resurrection while others do not.