In the introduction of his paper with Li-Xin Li Can the Universe Create Itself?, Gott constrasts his theory's approach to the first cause with that of the No Boundary proposal:"Often, the beginning of the universe, as in Vilenkin's tunneling model and Hartle and Hawking's No Boundary model, is pictured as being like the South Pole of the Earth and it is usually said that asking what happened before that is like asking what is south of the South Pole. But, suppose the early universe contains a region of closed timelike curves. Then, asking what was the earliest point might be like asking what is the easternmost point on the Earth. You can keep going east around and around the Earth - there is no eastern-most point. In such a model every event in the early universe would have events that preceded it."
From http://www.ipod.org.uk/reality/reality_intelligent_universe.asp by Andrew Thomas