So if I think that (something like) the Self-Indication Assumption is correct, what about Nick’s standard thought experiment in which the silly philosopher thinks she can derive the size of the cosmos from the fact she’s alive?
Well, the experiment does worry me, but I’d like to note that self-sampling without self-indication produces, in fact, a very similar result (if the reference class is all conscious observers, which Nick’s version of the experiment seem to assume). I give you The Presumptuous Philosopher and the Case of the Twin Stars:
Physicists have narrowed down the search for the Theory of Everything to T1 and T2, between which considerations of super-duper-symmetry are indifferent. We know that the cosmos is very big, to the tune of containing a trillion trillion galaxies, most of which are expected to contain life. But there’s a twist: According to T1, all but one in a trillion galaxies should consist entirely of twin star systems. T2 does not make this prediction. Physicists are preparing to do a simple test that would decide between the theories. Enter the Presumptuous Philosopher: “Guys, our galaxy has lots of single-star systems. The conditional probability of this if T1 is true and we’re a random sample from all conscious observers is only one in a trillion! Stop doing this silly experiment and do something else instead!”
If you accept this thought experiment (which requires only self-sampling) but reject a variation where T1 is ruled out because it predicts that cosmological death rays will make life impossible in all galaxies but one in a trillion (which requires self-sampling), then I think you’ve allowed yourself to be suckered into implicitly assuming that conscious observation is something ontologically fundamental. Though I accept that you may not be convinced of this yet :-)
(Side note: Lest you be biased against the philosopher just because she dares to apply probability theory, do also consider the case where T1 predicts that Mars had a chance of 4⁄5 per year of flying out of the solar system since it came into existence—and beat those odds by random chance every single time. Of course, in that case, the physicists would already be convinced that her reasoning is sound, to the tune that they would already have applied it itself.)
So if I think that (something like) the Self-Indication Assumption is correct, what about Nick’s standard thought experiment in which the silly philosopher thinks she can derive the size of the cosmos from the fact she’s alive?
Well, the experiment does worry me, but I’d like to note that self-sampling without self-indication produces, in fact, a very similar result (if the reference class is all conscious observers, which Nick’s version of the experiment seem to assume). I give you The Presumptuous Philosopher and the Case of the Twin Stars:
If you accept this thought experiment (which requires only self-sampling) but reject a variation where T1 is ruled out because it predicts that cosmological death rays will make life impossible in all galaxies but one in a trillion (which requires self-sampling), then I think you’ve allowed yourself to be suckered into implicitly assuming that conscious observation is something ontologically fundamental. Though I accept that you may not be convinced of this yet :-)
(Side note: Lest you be biased against the philosopher just because she dares to apply probability theory, do also consider the case where T1 predicts that Mars had a chance of 4⁄5 per year of flying out of the solar system since it came into existence—and beat those odds by random chance every single time. Of course, in that case, the physicists would already be convinced that her reasoning is sound, to the tune that they would already have applied it itself.)