Jonathan Colvin writes:
> In the process of writing this email, I did some googling, and it seems my
> objection has been independantly discovered (some time ago). See
> In particular, I note the following section, which seems to mirror my
> argument rather precisely:
> "It seems hard to rationalize this state space and prior outside a religious
> image where souls wait for God to choose their bodies.
> This last objection may sound trite, but I think it may be the key. The
> universe doesn't know or care whether we are intelligent or conscious, and I
> think we risk a hopeless conceptual muddle if we try to describe the state
> of the universe directly in terms of abstract features humans now care
> about. If we are going to extend our state desciptions to say where we sit
> in the universe (and it's not clear to me that we should) it seems best to
> construct a state space based on the relevant physical states involved, to
> use priors based on natural physical distributions over such states, and
> only then to notice features of interest to humans."
> I've looked for rebuttals of Hanson, and haven't found any. Nick references
> him, but comments only that Hanson also seems to be comitted to the SIA (not
> sure why he thinks this).
There was an extensive debate between Robin Hanson and Nick Bostrom
on the Extropians list in mid 1988. You can pick it up from the point
where Robin came up with the "rock/monkey/human/posthuman" model which
he describes in the web page you cite above, at this link:
You can also try looking this earlier thread,
and focus on the postings by Nick and Robin, which led Robin to produce
his formal model.
I think if you look at the details however you will find it is Robin
Hanson who advocates the "you could have been a rock" position and Nick
Bostrom who insists that you could only have been other people. This
seemed to be one of the foundations of their disagreement.
As far as the Self Indication Axiom, it might be due to such lines as
this, from Robin's essay you linked to:
"And even if everyone had the same random chance of developing amnesia,
the mere fact that you exist suggests a larger population. After all,
if doom had happend before you were born, you wouldn't be around to
consider these questions."
I think this is similar to the reasoning in the SIA.