Free will is the sensation of making a choice. The sensation is real, but the choice seems illusory. Laws of physics determine the future.

The central idea of string theory is quite straightforward. If you examine any piece of matter ever more finely, at first you'll find molecules, atoms, sub-atomic particles. Probe the smaller particles, you'll find something else, a tiny vibrating filament of energy, a little tiny vibrating string.

I wouldn't say that The Fabric of the Cosmos is a book on cosmology. Cosmology certainly plays a big part, but the major theme is our ever-evolving understanding of space and time, and what it all means for our sense of reality.

When general relativity was first put forward in 1915, the math was very unfamiliar to most physicists. Now we teach general relativity to advanced high school students.

You should never be surprised by or feel the need to explain why any physical system is in a high entropy state.

The fact that I don't have any particular need for religion doesn't mean that I have a need to cast religion aside the way some of my colleagues do.

The pinpoints of starlight we see with the naked eye are photons that have been streaming toward us for a few years or a few thousand.