Time Reborn: From the Crisis in Physics to the Future of the Universe

by Lee Smolin

As science progresses, aspects of nature once considered fundamental are revealed as emergent and approximate.

The fundamental physical theory we seek will not be about things moving in space. It will not have gravity or electricity or magnetism as fundamental forces. It will not be quantum mechanics. All these will emerge as approximate notions when our universe grows large enough.

The one ancient philosopher who did speculate about the paths taken by falling bodies – Aristotle – proposed an answer that was easy to disprove but nonetheless was blindly believed for more than a thousand years

Temperature is like this: Macroscopic bodies have temperatures, but single particles don’t, because the temperature of a body is the average of the energies of the atoms that make it up. Some physicists have proposed that time, like temperature, is meaningful only in the macro world but not relevant at the Planck scale.

our universe is the one thing that cannot be caused by or explained by something external to it, because it is the sum of all the causes.

Newtonian physics can be considered an effective theory, applying to a domain in which speeds are much lower than that of light and quantum effects can be ignored. Within that domain, it remains as successful as it ever was.

Mathematics will continue to be a handmaiden to science, but she can no longer be the Queen.