If, therefore, Grace’s anthropic reasoning is correct then most of the time when a prehistoric group of humans settled a large, uninhabited island, that group went extinct.
This is, strictly speakig, not true. The anthropic reasoning involves some prior probability of extinction, which can be different for island settlers and space settlers.
This is, strictly speakig, not true. The anthropic reasoning involves some prior probability of extinction, which can be different for island settlers and space settlers.