bcrowell said:
Having looked into the theory a little this evening, what really impresses me is that although it is clearly falsifiable in principle, it appears to be extremely difficult to falsify in practice. Finding a two-solar-mass neutron star would definitely do it. Other than that, everything seems to be mired in the horrible complexity and uncertainty of the mechanisms of star formation, which we basically know nothing about.
Crowell, I like this summary very much! It is fair.
There may be ways of testing CNS that haven't been thought of yet. As more is learned about the mechanisms of star formation, and more early universe star formation is observed, ways of falsifying CNS may turn up. But at the present time there are only the 3 tests mentioned in the paper (one of which is the neutron star test Chronos is considering here.) This is not enough--I hope people will keep trying to find ways to falsify the conjecture.
Despite the scant testability, I like CNS for two reasons. It provides at least a partial answer to questions about why nature provides a rich periodic table of stable elements with e.g. carbon chemistry. Also to questions about why physical constants allow stars, including supernovae, to exist. We can't claim that CNS is right, but it can give some alternative to challenge the claims of necessity for "designer" and "give up it's just luck" multiple existence hypotheses.
1. "designer" idea: some people argue the necessity of physical constants having been consciously adjusted to make the world congenial to life, say because of carbon chemistry. CNS gives a tentative
rebuttal: carbon compounds seem to facilitate star formation. (And a prediction that we will see lower rates of star formation in the early universe before the first generation of short-lived stars spread such heavier elements around.)
2. "dumb luck" idea: some people argue we must necessarily abandon the search for selective causes. They presume that all different worlds exist and our world just happens to be one where conditions are suitable for us. This means giving up looking for reasons that favor the physics we see. CNS provides a challenging
counterexample to this: showing that we don't HAVE to give up. We can still use intellect to propose testable reasons why the constants of physics are what they are.
From my perspective the CNS conjecture can benefit us as a rebuttal and counterexample even if it is eventually falsified. It helps sustain the discipline of the empirical tradition, by challenging us to propose other testable reasons for how the world is, rather than putting it all on Luck or a Designer. If CNS were to be falsified, I would hope that some other selective cause idea would be proposed to take its place. We should have several!
Chronos said:
EXO 0748-676 was a potential CNS buster at 1.8-2.1 solar masses. More recent measurements by Ozel constrain it to 1.55 +- .12 solar masses -
http://arxiv.org/abs/1007.0647. Still a challenge to CNS but not quite as convincing. It's all about the EOS ...
I'm impressed that you spotted that, Chronos. Thanks. I'm curious how you keep track, did you do a search with keyword "EXO 0748-676" or what?
