  This paper uses anthropic reasoning to argue for the Non-Arbitrary Existence
Hypothesis (NAEH). Nick Bostrom's Self-Sampling Assumption (SSA) combined with
NAEH is compared against SSA without such an assumption and also SSA with the
Self-Indication Assumption (SIA). When considered in the light of various
thought experiments, including the Incubator Gedanken, the Doomsday Argument,
the Presumptuous Philosopher and Bostrom's Adam and Eve thought experiments,
SSA with NAEH is found to give the most plausible results. The possibility of
principles not explicitly considered in the paper being superior also is
discussed but found to have limited plausibility.
