[ExI] Drake Equation Musings

[BillK]

On 17 May 2016 at 09:42, Anders Sandberg  wrote:
<snip>
> [ Some of you will by now wonder why I do not say we should expect an
> uncertainty of p running over loads of orders of magnitude, like the life
> probability does in our paper. The reason is that there is a curious
> asymmetry between reasons intelligent life may not emerge and reasons
> intelligent life may be quiet. The first group is largely conjunctive:
> "intelligence will happen if X and Y and Z and W and... happens" - if one of
> the conditions in the chain is missing, there is no intelligence.
> Explanations for silence have the form "X or Y or Z or W or ...". If one of
> them is wrong, nothing happens to the outcome. But their probabilities need
> to sum to nearly exactly 1, and if one of them actually has less probability
> than needed then the entire explanation breaks. ]
>



That's logical thinking if you have no evidence for either probability.

But we do have evidence! Life on earth started immediately, as soon as
the newly formed planet had cooled down sufficiently. Unless you have
evidence that Earth is unique in the universe, (the Rare Earth
hypothesis), then life should be everywhere, in every niche where it
can survive, just like in extreme environments on Earth.

We don't have any evidence for why advanced civilisations might be
'quiet', though we can think of many possibilities. As you say it
would be nice if we could think of a universal reason that *must*
apply to every advanced civilisation. But we haven't advanced enough
yet. When the Singularity hits us, it will probably become obvious.
Duh!

Of course, sadly that reason might be that reaching the Singularity
kills civilisations. But, nil desperandum!  :)

BillK