Four philosophical questions to make your brain hurt

I just came across an article from a 2008 edition of the BBC News Magazine which raises four epistemological, metaphysical, and ethical questions for the general (and impatient) reader. The four questions are:

• Should we kill healthy people for their organs?
• Are you the same person who started reading this article?
• Is that really a computer screen in front of you?
• Did you really choose to read this article?

Fascinating questions to ponder and discuss!