Can a person suffer radical change and still be the same person?

Are there human beings who are not persons at all?

Western philosophers, from the ancient Greeks to contemporary thinkers, gave the concept of "person" great importance in their discussions. They saw it as crucial to our understanding of our world and our place in it.

Prompted by tragedy -- a loved one's descent into dementia -- Warren Bourgeois explored Western philosophical ideas to discover what constitutes a "person." The first edition of Persons -- What Philosophers Say About You was...