No. You appear to be claiming that there are many, many, many hospitable conditions. . "There could be many different sets of conditions from which many different varieties of life could emerge. Life could emerge given a wide range of possible physics"
That runs counter to current thinking and therefore if you are going to make this claim you must justify why you are going against the consensus. I am not saying you are wrong, merely that such a statement requires justification.
I have on my book shelf, “Evolution, the Triumph of an Idea”, by Zimmer. It is a companion book to the PBS series. I have referred to it periodically over the years and so I pulled it down when you brought up Brownlee and Ward. There is no reference to Brownlee and one reference to Ward regarding the extinction of Ice Age mammals. I Read the chapter where that reference appeared and not surprisingly it was the chapter on Extinctions (which covers forty pages).
I began to see why Brownlee and Ward conclude that Earth’s advance life forms are rare in the universe. So since I walk a lot and the library is well within my daily walking distance I stopped in and picked up “Rare Earth”. I have been scanning it and looking at the contents, index, and especially the references that I alway like to read (sometimes instead of reading the whole book). But of note is the last topic in Chapter eight. It is two or three paragraphs under the heading, “A model of Planetary Extinction”. I think I can type it out in two minutes so here goes:
"We can summarize the implications of Earth’s history of mass extinctions with regard to the Rare Earth Hypothesis as follows. Mass extinctions probably occurred rarely during the long period in Earth history when life was only of a bacterial grade. With the evolution of more complex creature, such as eukaryotic cells, however, susceptibility to extinction increased. With the advent of abundant complex animals in the Cambrian, vulnerability to mass extinction may have reached a peak, because diversity was very low. As more and more species evolved within the various body plans, susceptibility to extinction decreased again."
"On any planet, the number of mass extinctions may be one of the most important determinants of where animal life arises and, if so, how long it lasts. In planetary systems with large amount of space debris – and thus a high impact record – the chance that animal life will arise and persist will surely be much lower than in systems where impacts are few. In similar fashion, inhabiting a cosmic neighborhood where large amounts of celestial collisions, supernovae, gamma ray bursts, and other cosmic catastrophes occur will also reduce a planet’s likelihood of attaining and maintaining animal life."
"It appears that the best “life insurance” is diversity."
Note: Wow am I rusty at typing but there it is. Extinctions as I suspected, play an important role in the Rare Earth scenario. And I agree that the specific course of life on Earth includes a lot more than the generative and evolvative forces (not forces in the same sense as gravity, EM, strong and weak).
. I suppose everyone is in agreement with me on this, right? So this thread will end with the OP, case closed?
