Chapter 8

In this chapter, Stephen Hawking discusses the possibility of the universe having a beginning at the big bang and an ending at the big crunch. He looks at models that could explain the uniformity of the observable universe, including the inflationary model, which proposes that symmetry between the four fundamental forces may have held for some period after the big bang. He also proposes that a quantum theory of gravity should contain two properties: Richard Feynman's sum over histories and Albert Einstein's model of curved space-time. From this, Hawking hypothesizes a finite universe that has no boundaries, implying that there may not be a singularity at the beginning or end of time and that the normal laws of science could hold at the big bang and/or the big crunch. This leads to questions about the existence of God and the nature of the universe.