Finding a good definition for life has been a long-term challenge in philosophy and biology. Recent discoveries in biology and astronomy have given us an opportunity to reassess our answers to this perennial question. Meanwhile, modern interpretations suggest that Aristotle's definition of life may be more compatible with modern science than was long believed. The goal of this project is to trace the history of definitions of life, keeping an eye on questions of purpose, function, and proper activity from a scientific perspective and questions of value from a theological perspective. There will be a direct impact on the academic community through a biweekly discussion group at MIT and published papers. There will also be an impact on the general public through a book, a blog, and public speaking. Our goal is to change the tenor of the definition of life question by identifying the primary interests of participants and shifting focus to answerable aspects of the question.