Thanks for the reply, I do find the source article that you quoted to be a little short on how the probabilities were arrived at.... and many of the probabilities seem to be linked. I'm not sure that just a simple multiplying of them all together (suggesting independence, and even with the fudge factor at the end) is a wise way of evaluating so many variables... I have the same problems with Drake as well, in that most of the variables are pretty much unknown quantities... but at least with Drake that is restricted to a few terms rather than a gigantic list of unknowns!

I'm not sure that the logic at the end is one that I would make... as it isn't quite completely supported (even by the probability argument that the writer makes). The seeming unlikeliness of the probability of life (as given by the author, not that I accept it yet...) and the obvious evidence of life (here on Earth) would suggest to me that we don't understand some of the terms and mechanism to explain the disparity... I wouldn't make the conclusion that there is a creator (I wouldn't definitely rule it out, but I wouldn't definitely accept it... small difference!).

With your zinc example, this is a clear case for mechanisms to slowly gather the materials required over time (or a divine creator if that is your preferred explaination!) Definitely, if zinc was to be spread evenly that would be weird... but like most things, on a smaller scale, it tends to clump. And in that clumpiness we see the potential for more clumping.... (lol, technical terms...)... in the same way that stars form, despite the large scale uniformity of the distribution of matter/energy... and in these clumpy stellar regions there are things that defy the "normal" state of affairs that are suggested by the most abstract levels of physics.

Again, the lack of detection of "Earth-like" exo-planets is an artifact of our limitations on detection. Large, massive objects are easier to detect due to the effect that they have on the light spectra on the host star. Small objects like the Earth are beyond our current ability to reliably detect... but getting closer!

Anyway, an interesting conversation and insight... I will have an extra SBI share for you!