Nick Szabo on acting on extremely long odds with claimed high payoffs:
Beware of what I call Pascal's scams: movements or belief systems that ask you to hope for or worry about very improbable outcomes that could have very large positive or negative consequences. (The name comes of course from the infinite-reward Wager proposed by Pascal: these days the large-but-finite versions are far more pernicious). Naive expected value reasoning implies that they are worth the effort: if the odds are 1 in 1,000 that I could win $1 billion, and I am risk and time neutral, then I should expend up to nearly $1 million dollars worth of effort to gain this boon. The problems with these beliefs tend to be at least threefold, all stemming from the general uncertainty, i.e. the poor information or lack of information, from which we abstracted the low probability estimate in the first place: because in the messy real world the low probability estimate is almost always due to low or poor evidence rather than being a lottery with well-defined odds.
Nick clarifies in the comments that he is indeed talking about singularitarians, including his GMU colleague Robin Hanson. This post appears to revisit a comment on an earlier post:
In other words, just because one comes up with quasi-plausible catastrophic scenarios does not put the burden of proof on the skeptics to debunk them or else cough up substantial funds to supposedly combat these alleged threats.
When pondering the possibilities where we live given lack of grand unified theory 'of everything', you can't assume your physical intuitions hold true. In fact you should assume the opposite. The MWI is just an example of how philosophical argument that looks entirely invariable admits defeat from possible physics, in a way in which the mathematics - which philosophy mimics - does not. That means validity of argument requires validity of intuitions, which are reasonably very unlikely to be valid in any grand sense. There's also historical example: a lot of philosophers assuming Euclidean geometry is the only logically possible kind of geometry, without even noticing that they are making such assumption, up until mathematicians came up with alternative.
You assume that the probability of being among either group depends to number of yous within that group (rather than something entirely different), to do anthropic reasoning beyond tautological 'we can't observe universes where we can't be alive'. In my opinion this is a case of wild guess over unknowns, totally false precision.
I came up with a clearer example of how something totally different may actually make a lot more sense: Solomonoff induction on codes that model various universes. A model of the universe outputting the data matching your internal self-perception must not only contain yourself, but must include the code that finds yourself within that model, so that output begins with sense data. It is then clear that the code that picks one of yous out of a model full of all sorts of simulations may easily be larger than the code that picks you out of the world where there is just one you, but the number of various others is much smaller.
I'm not arguing that Bostrom is bad for a philosopher. I am outlining how in philosophy you just make all sorts of assumptions that you don't notice are wild guesses, and how the field is basically built on false precision. I.e. you assume that the probability of being within some huge set full of yous and non-yours is independent of number of non-yous, which is just a wild guess. Connect together half a dozen implicit wild guesses with likelihood of correctness of overly generous 1 in 100 each , and we're speaking of probability of correctness in the range of 10^-12 . Philosophy is generally like this.
I believe this falls under Nick Szabo's complaint about false precision.
Also, a paper by Steven Weinberg on usefulness of philosophy.
It seems to me that funding philosophical works in this field may actually be actively harmful, due to establishment of such false precision and prejudices. It's like funding 'embracing bias, imprecision, and making your mind up before checking where the mathematics will lead you'.
That's the whole point: very low probability of being right. There's a crucial difference: the methods Newton employed managed to achieve a non-zero (and not negligible) truth finding rate. So he made something that does not look silly. Even with this, most of stuff was quite seriously wrong.
Do you think it's "generous" to assign only 99% probability in the negation of "the probability of being within some huge set full of yous and non-yours is independent of number of non-yous" where "you" is interpreted to include all your observations? That seems like insane overconfidence in a view that goes haywire in simple finite discrete cases.