Big Bang or Big Bounce?

For over fifty years, since the discovery of the cosmic microwave background, the consensus view has been that the universe had a definite beginning, known as the big bang. In this talk, I will review the standard inflationary paradigm and how it is supposed to explain the large-scale structure of our universe. We will then consider whether it is possible to replace the big bang with a big bounce, discarding the idea of a “beginning” altogether and perhaps obtaining a more natural explanation of the large-scale properties of the observable universe.