The Recursive Universe (William Morrow, 1984). For a popular survey of the use of simulations in science more generally, see John L. Casti,

Would-Be Worlds: How Simulation Is Changing the Frontiers of Science (Wiley, 1997).

For a discussion of whether we are living in a historical simulation, see Nick Bostrom, 'Are You Living in a Computer Simulation?’,

53(211) (2003): 243-55. The author also runs a website at

http://www.simulation-argument.com

where this paper, as well as a variety of synopses and responses are available.

The computer scientist Robert Bradbury argues that we will be able to build a Matrioshka brain, a planet-sized supercomputer that can carry out up to 10

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computational operations per second within the next century. (More information on Matrioshka brains is at

http://www.aeiveos.com/~bradbury/MatrioshkaBrains. ) Bostrom (247) argues that we need considerably fewer, namely a maximum of 10

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