It seems we've moved on and, perhaps, glossed over the "improbablity issue". I'm refering back the discussion (by CS I think) about the extreme improbability of a calcium atom from a star ending up in a bone in his arm.
But this was never connected to the whole topic.
It is, indeed,
extremely improbable that a specific calcium atom would end up in that particular place. In fact, it's so improbable that one might suggest that it can never, ever occur.
However, that's the mistake of looking at how totally unlikely it is that a specific person (namely me) will win a specific drawing of a lottery. Never, seems to be the answer.
But
some lucky, annoying bastard will win my money. That has a very, very high probability.
Likewise some calcium atom out of untold trillions will end up somewhere in someone's arm and that seems to have a pretty high probability under the conditions that are extant.
In the same way, the chain of events that leads to the chemistry we call "living" arising from chemistry we'd agree is not living maybe very improbable, unless there are either very, very many different chains that work or many, many different attempts are made to arrive at the end of the chain. (If I live long enough the chances of my winning the lottery get much better.)
Since we don't know the number of different paths to a win (life) calculating the odds can be off by 10's of orders of magnitude. We can make guesstimates of the number of trails and those can easily produce results with 20 or 30 figures.
What should be concluded from this?
Any discussion based on improbability is dumb and fruitless. Life arose, maybe it was a very, very lucky fluke and maybe it is an inevitable consequence of the initial conditions on earth (or some where in between). If it was very, very, very unlikely then one is entitled to ask if someone was loading the dice. But there is no hint that it is unlikely yet.