In Modern Physics and Ancient Faith, I discussed some of the speculative scenarios in which time has no beginning and the Big Bang is merely the beginning of one part of the universe or one epoch in its history. Another line of physics speculation accepts the idea that time has a beginning, either the Big Bang that occurred some 15 billion years ago, or some earlier perhaps even bigger Bang, but seeks to give that beginning a scientific explanation. Many scientists are under the impression that such an explanation would render a divine creator superfluous. As I will explain later, this notion is based on a misunderstanding of the idea of Creation. However, let us put that issue aside for now and focus on the scientific ideas.
Theories of the beginning of the universe generally are formulated within the field called “quantum cosmology.” There are several motivations for this work. At the most basic level, scientists seek to understand phenomena, and the Big Bang is a phenomenon. (I will refer to the beginning of time as “the Big Bang,” whether it is the Big Bang that happened about 15 billion years ago or some earlier event.) Scientists want to understand it in the sense of finding an adequate mathematical description of it in terms of the laws of physics. There is no reason why the Big Bang should not have such a description, and if such a description is possible it is an important goal of science to find it.