writes: Some researchers now see popular ideas like string theory and the multiverse as highly suspect. These physicists feel our study of the cosmos has been taken too far from what data can constrain with the extra "hidden" dimensions of string theory and the unobservable other universes of the multiverse. Of course, there are many scientists who continue to see great promise in string theory and the multiverse. But, as Marcelo and I wrote in The New York Times last year, it all adds up to muddied waters and something some researchers see as a "crisis in physics."
Smolin and Unger believe this crisis is real — and it's acute. They pull no punches in their sense that the lack of empirical data has led the field astray. As they put it:
"Science is corrupted when it abandons the discipline of empirical validation or dis-confirmation. It is also weakened when it mistakes its assumptions for facts and its ready-made philosophy for the way things are."
Thus, the goal of The Singular Universe and The Reality of Time is to take a giant philosophical step back and see if a new and more promising direction can be found. For the two thinkers, such a new direction can be spelled out in three bold claims about the world.
- There is only one universe
- Time is real
- Mathematics is selectively real
Taken together, these three claims constitute a significant departure from mainstream ideas in physics. But their most important consequence is that nothing, not even the laws of physics, live above time. The universe is time-bound and time-saturated. Thus, there is no eternal reality of perfect mathematical form. Even the laws of physics themselves must be subject to change. That is the most radical of Unger and Smolin's radical ideas.