To a theoretical physicist, there is no greater joy than to see that this curious activity we call calculation - the depositing of ink on paper, followed by throwing away the paper and depositing new ink on more paper - can actually tell us something about reality.
I'm a cosmologist. All I do is cosmology.
The idea of combining the physics of modern particle theory with cosmology was very young when I started working on cosmology.
If you bang two electrons together with enough energy, you produce protons. If there are no independent laws, then all the properties of protons must somehow be 'known' by the electrons. By extension, every elementary particle must carry around enough information to produce the entire universe. I find that difficult to believe.
If we assume there is no maximum possible entropy for the universe, then any state can be a state of low entropy.
If there's no limit to how big the entropy can get, then you can start anywhere, and from that starting point, you'd expect entropy to rise as the system moves to explore larger and larger regions of phase space.
It is rather fantastic to realize that the laws of physics can describe how everything was created in a random quantum fluctuation out of nothing, and how over the course of 15 billion years, matter could organize in such complex ways that we have human beings sitting here, talking, doing things intentionally.
In the context of general relativity, space almost is a substance. It can bend and twist and stretch, and probably the best way to think about space is to just kind of imagine a big piece of rubber that you can pull and twist and bend.
Relativity can, for instance, explain that the universe had once been clumped into a dense fireball. But it can never explain how matter actually behaved.
Reformed Jews don't have to quite believe in God.
