Pilate was a well educated man, and understood the writings of the "greats". This was basically all Greek skepticism, which is the foundation of the modern world. i.e. Skepticism was and is the dominant philosophical school of thought, although there are some serious bastardisations and perversions. But that's best left to another discussion.
So, Pilate's response with "What is truth" is a direct reflection of his education and understanding of philosophy. (That's a circular argument, but it's enough for anyone to do their own checking on it, and it needed to be made explicit for there to be an actual purpose to this footnote that could have been skipped if I'd simply avoided the Pilate quote... but since it's such a cool quote, I simply couldn't avoid including it!)