When and how did the universe begin? Why are we here? Why is there something rather than nothing? What is the nature of reality? Why are the laws of nature so finely tuned as to allow for the existence of intelligent beings like ourselves? And, finally, is the apparent existence of our universe evidence of a "God-like structure", who has set all things in motion—or does science offer another explanation?
The most fundamental questions about the origins of the universe and of life itself, once the province of philosophy, now occupy the territory where scientists, philosophers, and theologians meet—if only to disagree. According to quantum theory, the cosmos does not have just a single existence or history, but rather the future influences the past and many histories of the universe exist simultaneously. When applied to the universe as a whole, this idea calls into question the very notion of cause and effect. But the “top-down” approach to cosmology would say that the fact that the past takes no definite form means that we create history by observing it, rather than that history creates us. We ourselves could just be the product of seemingly random quantum fluctuations in the very early universe. Part of the quantum theory predicts that the “multiverse”—ours own universe being just one of many universes—appeared spontaneously out of nothing, each multiverse possessing its own different laws of nature. A “model-dependent” theory of reality might be the best we can hope to find.