I have made sticky (sent to the top of the blog post list) the post Andreas Schueler wrote about the biological aspects of personhood, life and thus the ramifications on views on abortion. The post is excellent and reflects issues with nominalism and realism: how we attach abstract, conceptual labels to real, material things. And the problems therein.
A new commenter has resurrected the thread, and Andreas is being his usual robustly erudite self.
Join in the debate!
The post is here:
Here some other relevant posts: