 We are now ready to move to the final step, taking us into speculative metaphysics of physics. In the last fifty years various scientists (see Zuse 1982; Fredkin 1993; Wolfram 2002) have advanced a bold conjecture: that the physical universe is, fundamentally, a discrete computational structure. Everything in our world—quarks, trees, human beings, remote galaxies—is just a pattern in a CA, much like a glider in Life. 