Mary-Jane Rubenstein, associate professor of religion, is the author of Worlds Without End: The Many Lives of the Multiverse, published by Columbia University Press, 2014. “Multiverse” cosmologies imagine our universe as just one of a vast number of others. While this idea has captivated philosophy, religion and literature for millennia, it is now being considered as a scientific hypothesis—with different models emerging from cosmology, quantum mechanics and string theory. Beginning with ancient Atomist and Stoic philosophies, Rubenstein links contemporary models of the multiverse to their forerunners and explores the reasons for their recent appearance. One concerns the so-called fine-tuning of the…