# The primary political and philosophical issue of the next century will be the definition of… by Ray Kurzweil > "The primary political and philosophical issue of the next century will be the definition of who we are." > **— Ray Kurzweil**, *The Age of Spiritual Machines (1999)* Verification Status: Unverified — exact wording/source has not yet been independently confirmed against a primary source; source clue: The Age of Spiritual Machines (1999).