A professor, biologist, and physiologist argues that modern Darwinism’s materialist and mechanistic biases have led to a scientific dead end, unable to define what life is—and only an openness to the qualities of "purpose and desire" will move the field forward. Scott Turner contends. "To be scientists, we force ourselves into a Hobson’s choice on the matter: accept intentionality and purposefulness as real attributes of life, which disqualifies you as a scientist; or become a scientist and dismiss life’s distinctive quality from your thinking. I have come to believe that this choice actually stands in the way of our having a fully coherent theory of life." Growing research shows that life's most distinctive quality, shared by all living things, is purpose and desire: maintain homeostasis to sustain life. In Purpose and Desire, Turner draws on the work of Claude Bernard, a contemporary of Darwin revered among physiologists as the founder of experimental medicine, to build on Bernard’s "dangerous idea" of vitalism, which seeks to identify what makes "life" a unique phenomenon of nature. To further its quest to achieve a fuller understanding of life, Turner argues, science must move beyond strictly accepted measures that consider only the mechanics of nature. A thoughtful appeal to widen our perspective of biology that is grounded in scientific evidence, Purpose and Desire helps us bridge the ideological evolutionary divide.