In Transparent Newcomb’s Problem, your decision determines whether you existed when you were making the decision. It’s not valid to conclude that you exist merely from subjective observation of your own existence, because such observation can take place within counterfactuals, and you wouldn’t be able to tell that you are within a counterfactual or actuality other than by reasoning about (or determining) your situation’s actuality status. Like math, existence can’t be perceived by looking at rocks.
In a single universe interpretation, we can posit biogenesis is rare, but we do know it happened at least once in ~two trillion galaxies worth of stars in ~13 billion years.
So this already doesn’t follow, your conclusion is true, but doesn’t require MWI. Even without MWI, observing our own existence doesn’t tell us anything about the probability of biogenesis (and subsequent development of generally intelligent life).
In Transparent Newcomb’s Problem, your decision determines whether you existed when you were making the decision. It’s not valid to conclude that you exist merely from subjective observation of your own existence, because such observation can take place within counterfactuals, and you wouldn’t be able to tell that you are within a counterfactual or actuality other than by reasoning about (or determining) your situation’s actuality status. Like math, existence can’t be perceived by looking at rocks.
So this already doesn’t follow, your conclusion is true, but doesn’t require MWI. Even without MWI, observing our own existence doesn’t tell us anything about the probability of biogenesis (and subsequent development of generally intelligent life).