Can we reason about our place in the universe without defining “us�, or Which of Occam's Razors should Wigner use to shave his quantum Friend?

Modern cosmology has revived interest in some early 20th century puzzles that had seemed to be more philosophical than scientific, the problems of Boltzmann’s brain and Wigner's friend.  The inability of a complete understanding of a physical system’s state and dynamics to reveal whether it is conscious plagues both ethics (“Which systems have rights?�) and cosmology (“What grounds do we have for believing that we are inhabitants of a young live universe rather than fluctuations in an old dead one?).  By universalizing Occam’s razor algorithmic information theory offers a way forward without defining consciousness or counting observers.

Speaker: Charles Bennett, IBM Research