Nereid said:
Should we also avoid reading anything written by Newton or Darwin? After all, they were clearly influenced by all kinds of strange and wonderful religious-based ideas
"Rare Earth", IMHO, is well worth reading; if you don't want to buy a copy, then check it out from your local library. Perhaps I could start a thread, specifically to discuss the approach Ward and Browlee use, the assumptions, etc!
I'll see if there's a copy of Darling's book in my local library, sounds like it could also be a good read.
Found it, read it. It's a review of the current state of astrobiology, written by a science writer. In this it differs considerably from "Rare Earth"; it isn't out to make one case or another.
The article to which Evo gives a link says: "Darling begins with a point-by-point scientific critique of the Rare Earth hypothesis. The hypothesis essentially says that for life to evolve and survive beyond the microbial stage a very special combination of factors must prevail (such as presence of a large moon to stabilize the planet's orbit, a Jupiter-size planet to sweep up killer asteroids, the occurrence of plate tectonics, and a sun with high "metallicity") and that these other factors are both rare in themselves and absolutely indispensable to complex life. Darling examines each in turn and concludes that the hypothesis is based on circular reasoning and that the proponents have fallen into the trap of going out of their way to find reasons why Earth is special.[/color]" Well, I'll reserve judgement on how good a summary of Darling's thesis this is, but as a summary of Ward and Brownlee's, it stinks. For a start, like all good scientists, the Rare Earth authors are at pains to point out the tentative and provisional nature of all their conclusions, so "absolutely indispensable" is hardly accurate.
Well, the SCICOP review of Darling stinks too.
Darling's book devotes only one chapter (out of 9) to the Rare Earth ideas, their authors, the influence of the creationist, politics and US funding for astrobiology (etc). In fact, Darling is quite careful to give the ideas in Rare Earth - and the authors - credit for quite a lot. Darling is also careful - though perhaps not so fastidious as Ward and Brownlee - the emphasise the tentative nature of all astrobiological results, and states clearly that there are no compelling observations (etc) which rule out the Rare Earth idea.
Darling's examination of the weaknesses of the Rare Earth idea is somewhat selective - he looks at 'A Large, Nearby Moon', 'Catastrophic Impacts', 'Extrasolar Planets', Jupiter's Protection', 'Metalicity', and 'The Galactic Habitable Zone'; he doesn't look at plate tectonics. As Darling's intention is a review, he is able to take each of these 6 points and present some counters; fair enough. What's lost, perhaps, is the range of views on each item, and the extent to which they're inter-related - i.e. a single, coherent 'Common Earth' case.
Further, some of Darling's own counters to the 6 Rare Earth items are weak, and one has already been overturned - there is now considerable evidence that planetary systems are rare in low metallicity environments (at least, systems with Jovian-sized planets).
Next, 'circular reasoning'. Trouble with SETI, and much of astrobiology, is that we have a sample of but 1, so it must surely be nigh on impossible to avoid 'circular reasoning', no matter what thesis is being proposed.
It seems that the 'circular reasoning' critique is of the SCICOP reviewer's making; Darling spends some time - as does everyone serious in this field - talking about the limitations of a single sample.
