Some thinkers suppose that the prior probability of human beings (as we know them ™) evolving is miniscule. This is not so. The probability is one, as can be see from the completely radical anthropic principle (CRAP).

It is readily shown that the physical constants of the universe have to be very close to the values that they actually have for it to be possible at all for life to exist and evolve. [See _The Cosmological Anthropic Principle_ by Barrow and Tipler for discussion in detail.] It has also been shown that the solutions of general relativity permit time travel. It can be shown that, in due course, intelligence will evolve to the point any physically feasible technology will be implementable [Clarke, Stapledon]. It follows that the point will be reached in the future history of the universe where time travel over arbitrarily large extents of time will become possible. It can be shown that the percentage of the universe accessible to an intelligence approaches 100% for omega <=1 and sufficiently long periods of time. {Asimov, Gamow]. It follows that all but a negligible fraction of the resources of the universe will be available to intelligence, given sufficient time. It therefore follows that an arbitrary remaking of the history and physical structure will happen at some point in the future history of the universe.

The problem of restructuring the history of the universe is a problem that has been extensively discussed. [Niven, Gerrold, Bova.] Basically it is a problem in multi-dimensional chaos theory. Gerrold establishes the existence of strange attractors [_The Man Who Folded Himself_]. Bova demonstrates the existence of a stable attractor basin revolving around an intelligence altering the universe to bring itself into existence. [The Orion series.] Niven purports to demonstrate that all attractors are unstable and that all universes which permit time travel evolve to a state in which time travel is impossible. In a brilliant analysis Nathan Childers [_A Preliminary Note On The Application Of Chaos Theory To Classical Time Travel_, Burning Cross Publications, 2007] shows that Niven degeneracy operates too “slowly” to empty sufficiently large Bova basins. Childers goes on to show that Bova basins merge into a single basin at a calculable point in the future.

In short, as Childers notes, “We may not be living in the best of all possible worlds, but we are living in the world we will have decided to live in.”