Kelly: The extreme view would be that all these bits that make up atoms are running on a very big computer called the universe, an idea first espoused by Babbage.

Gleick: That makes sense as long as this metaphor does not diminish our sense of what the universe is but expands our sense of what a computer is.

Kelly: But as you note, some scientists say that this is not a metaphor: The universe we know is only information.