Chapter 2, The Shape of Time Summary and Analysis

Hawking believes that any good scientific theory should be rooted in the philosophy of science advanced by Karl Popper. On his view, mathematical models describe and unify observation and can make predictions and be falsifiable. If positivism is true, we cannot say what time it is; we can only describe what makes good predictions. Newton's model suggested that time and space were not affected by events around them; philosopher Immanuel Kant worried that this implied time was infinite; but then why would the universe be created now rather than at some other point?

This was only a problem for Newton, not Einstein. General relativity combined time with space to form four-dimensional spacetime. Objects in spacetime attempt to move in straight lines, but because of the curvature of spacetime, paths appear bent as if...