While the Grabby argument does provide a reason why P(observer is early | observer’s species is confined to one planet) is not ridiculously small, it doesn’t at all explain why P(observer is early) is not ridiculously small. The Grabby hypothesis actually makes the latter probability very much tinier than without a Grabby hypothesis, since Grabby species have vastly more observers later in the timeline.
The simplest way to salvage this seems to be an additional hypothesis that whatever the Grabby entities are, they do not qualify as observers for the purposes of these anthropic arguments. Maybe they’re non-sentient but highly effective replicators that nonetheless prevent emergence of sentient life, and unlikely to ever evolve sentience.
In such a scenario, we get high P(observer is early): despite massive spread of something that prevents development of other species, no late observers exist.
While the Grabby argument does provide a reason why P(observer is early | observer’s species is confined to one planet) is not ridiculously small, it doesn’t at all explain why P(observer is early) is not ridiculously small. The Grabby hypothesis actually makes the latter probability very much tinier than without a Grabby hypothesis, since Grabby species have vastly more observers later in the timeline.
The simplest way to salvage this seems to be an additional hypothesis that whatever the Grabby entities are, they do not qualify as observers for the purposes of these anthropic arguments. Maybe they’re non-sentient but highly effective replicators that nonetheless prevent emergence of sentient life, and unlikely to ever evolve sentience.
In such a scenario, we get high P(observer is early): despite massive spread of something that prevents development of other species, no late observers exist.