It is time to face reality, California Institute of Technology theoretical physicist Sean Carroll says: There is just no such thing as God, or ghosts, or human souls that reside outside of the body. Everything in existence belongs to the natural world and is accessible to science, he argues. In his new book “The Big Picture: On the Origin of Life, Meaning, and the Universe Itself,” out this week from Dutton, Carroll describes a guiding philosophy along these lines that he calls poetic naturalism. It excludes a supernatural or spiritual realm but still allows plenty of room for life to have a purpose.

“I think we can bring ideas like meaning and morality into our discussions of the natural world,” Carroll says. “The ways that we talk about the universe are what make it meaningful.” He eloquently argues that point in his far-ranging book, which takes on the origins of consciousness, the likeliness of God based on a rigorous application of Bayesian probability statistics, and many other “big” questions that scientists are often loath to tackle.

Scientific American spoke with Carroll about his philosophy and how we can all take a closer look at just what we truly, deeply believe. [An edited transcript of the conversation follows.]

To read more, click here.