After the backlash comes the return to orthodoxy. In A Brief History of Time, Stephen Hawking suggested that physics was on the verge of solving the final puzzles of creation: the marriage of quantum physics and gravity and the origin of the universe. Since then, there has been a general sense of disappointment at the progress made by pretenders such as string theory. A number of works have suggested that mankind is still scrabbling around in the foothills of understanding, and that the universe may not even be ultimately explicable by our scientific and mathematical tools. Now, in a new magisterial account of the state of modern physics, Stenger reasserts the original optimistic outlook: physics has explained almost all that is and has been, and the few remaining pockets of resistance must soon fall.

He argues that the measure of the success of physics is that it can be encapsulated in a set of succinct equations which account for almost all human experience. In the first half of the book, he guides the reader through the historical development of physics, passing through special and general relativity and then dealing with particle physics, embarking on a brief excursion through statistical thermodynamics, before reaching the standard model and finally cosmology. He shows that this historical development can be seen as the expression of two principles: the principle of objectivity - that the laws of physics should be independent of our formulation of them and of our position in the universe - and the principle of symmetry. He shows that, in many cases, our theories are the simplest that can result from "point of view invariance" and symmetry. Thus, the universe is comprehensible.