[extropy-chat] Doomsday argument

[Lee Corbin]

Robin writes

>>You could not have been born anywhere except on Earth and in
>>the 20th century at that. You are the result of a baby with certain
>>genetic traits being raised in a 20th century type environment.
>>[If you had been raised under significantly different circumstances,
>>then you wouldn't be you.]

> Counterfactuals are one of our most powerful intellectual tools.

Agreed.

> the idea that we can imagine situations other than the one we find
> ourselves and ask ourselves what we should believe in such situations
> is a powerful way to clarify what we should believe in our real situation.

That is so!  But it is valid only so long as your identity remains constant
(or nearly so) under the counterfactual assumptions. "What would it be
like for me if I were a bat" is, as you know, a bad question. Likewise,
we can't "find ourselves" as you write, in the 14th century (unless someone
had some mighty fine simulations or hidden societies going on back then).

> "What if you didn't know when you were born or what civilization you live
> in" is an example of a useful thought-clarifying counterfactual.

I know that I *must* have been born in a 20th century type civilization
or simulation, or I wouldn't be me.  It would be someone else.  Even so,
were a Lee Corbin infant raised as a latter-day Wahhabist in Saudi
Arabia in the 1960s, the differences are just too great: it simply wouldn't
be me.

Therefore there can be no sense to taking the fundamental sample space
to be "all sentient creatures" or even "all creatures with human DNA".

Lee