In this informative and often surprising book, more than 100 notable scientists and scholars answer the question, "What do you believe even though you cannot prove it?" The responses range from the thought-provoking to seemingly trivial (or just plain silly). Professor of cosmology and astrophysics Martin Rees, for example, admits that he believes intelligent life is unique to our world (in sharp contrast to many of his fellow contributors). Alun Anderson, senior consultant to New Scientist magazine, believes cockroaches are conscious. Mathematician and science-fiction novelist Rudy Rucker believes in a multiplicity of universes. Susan Blackmore, who has written widely on the subject of consciousness, appears to believe that she doesn't exist. The contributors touch on a broad spectrum of subjects, from religion to science and many points in between. Although some of the responses are arrogant or nitpicky, the majority are thoughtful, honest, and revelatory of the contributors' own intellectual and philosophical biases. And the book certainly gets us thinking about our own deeply held, if entirely unprovable, beliefs.