Spike's was a very simple philosophy when we met him. I think that now he is forming one, and I think that the best thing that he has come up with so far is that a lot of being human is about degradation and pain and humiliation. I think he's starting to understand that for the first time. I think he got away from that by becoming a vampire and that's why he was so keen to stop being human, but he's getting back to being human now.
Spike's philosophies about life
BBC- Buffy - Features - James Marsters - Philosphically speaking