The Fabric of Reality presents a startlingly integrated, rational and optimistic world view - the result of taking seriously the deepest ideas of modern science and the philosophy of science. The four main strands of explanation involved in this synthesis are quantum physics and the theories of evolution, computation, and knowledge. These strands may seem unrelated, yet this book shows that they are so closely intertwined that we cannot properly understand any one of them without reference to the other three. Considered in isolation, each of them has explanatory gaps which have inhibited people from accepting them as being literally true. But considered jointly, they reveal a unified fabric of reality that is objective and comprehensible, and in which human actions and ideas play essential roles.
The most profound of the four strands is quantum theory, which contains our most fundamental knowledge of the physical world. Taken literally, it implies that there are many universes 'parallel' to the one we see around us, and that they are detectable through the astonishing phenomenon of quantum interference. The multiplicity of universes turns out to be the key to the unification of the four strands. For example, both the growth of scientific knowledge and the evolution of biological adaptations are best understood as multi-universe phenomena: normally, universes tend to become less alike with time, and the only two known processes capable of making them more alike are biological evolution and human thought.