[ExI] Fwd: [tt] The Habitable Epoch of the Early Universe

[Anders Sandberg]

On 12/12/2013 14:47, Eugen Leitl wrote:
> On Thu, Dec 12, 2013 at 02:13:36PM +0000, Anders Sandberg wrote:
>
>> Exactly. And now the diadem needs to think about what probability it
>> should assign to the existence of other diadems.
>
> If the diadem is honest, it cannot assign any probabilities.

That is actually not an answer. Read Jaynes, chapter 1 and 2.


>> SIA-believer diadem should favour theories where there are loads of
>> observers (but not necessarily diadems). However, the unique diadem
>
> The SIA diadem has no basis for that assumption either.

Yes, the SIA.

Now how you come to accept axioms of anthropic reasoning or not is a 
separate and tricky issue. Much of the research in the field is about 
this, or whether they can be derived from Bayesian probability or 
decision theory. (see the videos of the Oxford conference we had about 
it a few weeks back when they arrive online)

>> observer is also an "anomalous observer" - most observers are by
>> definition common, and they would get things more right when
>
> This is circular logic. You have no idea how common your class is,
> until you have an unbiased sample.

Yes, but I was not talking about your judgement of your situation in 
that sentence. Merely about the fact that in the generic case (it is 
always possible to construct contrived counterexamples) anomalous 
observers are going to be the minority compared to non-anomalous observers.

(This is incidentally why Boltzman brains are regarded as a headache in 
the philosophy of science: if they exist, then they do swamp "real" 
observers with anomalous ones)


-- 
Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University