Originally posted by @metal-brain
When I read Lee Smolin's "Three roads to Quantum Gravity" I was surprised at Smolin's confidence that space-time is discrete. Not everybody agrees with that and I used to be a skeptic myself, but I honestly don't know the answer. There are arguments for both sides so feel free to make your case for either side. I hope to learn something from it.
Lee Smolin is good at raising thought-provoking questions, but often falls short of furnishing convincing answers. And it is during those times when he is the least convincing that he frequently sounds the most sure of himself. Maybe it's just his writing style, but some of his chapters have the feel of going to church or listening to a sermon on the mount.
However, I've only read two of his books, and read some reviews about others. It so happens I just finished reading the second book, Time Reborn
, less than a week ago. I think I started it over two years ago, but kept putting it aside for months at a time on account of it being difficult to read -- and all for the wrong reasons. His attempts to describe many of the latest cosmological theories are often clumsy and vague to the point of being meaningless. A couple times I found it easier to understand what was going on by skimming through the original research papers he referenced. There's not a single equation in the entire book, and it is not a trivial matter to describe what are essentially mathematical constructs without using any mathematics. Most laymen's books on modern cosmology or quantum theory fail in this regard.
The first Smolin book I read was The Trouble with Physics
, which was much more engaging and convincing. That so-called "string theory" is verging on becoming a religion amongst the high priests of cosmology is a hard sell, and while he doesn't come out and say that as such, he strongly implies it and makes a good case for it.
So I think Smolin is a proponent of something called quantum loop gravity, which is an alternative to string theory.