A Christian Defending or Discussing thier faith..
Discussion is fine. Faith cannot be defended without entering into personal debate (tastebuds).
Example: "This is why I believe that Christ died for our sins."
is much different than
"Christ died for our sins and we must be forgiven, here's why and here's how to sign up"
I have read only a few of PS's but they seemed to lean toward the second exmaple. Which is why I call him an Apologist.
The way I see it is to be a Christian is to accept the Bible, and to accept the Bible is to defend the Bibles holes because they are many. Most Christians are Apologists, it is VERY hard to find someone who stands by their faith as absolute in their own heart.