And you think they are not qualified?
No one is. Nobody today has the knowledge necessary to determine that. They don't even understand all the properties of *this* universe that result from the "basic variables" (whatever *those* are, and no one knows *that* either) that go into making a universe, much less what *other* kinds of universes would or would not result from changes in those variables, nor what physical processes would be possible in those universes which do not exist in ours, nor what those unknown physical processes might or might not contribute to the capability of something to exist in those alternate universes that might be worthy of the name "life". Anyone who believes that this is knowable at this point in time is immensely foolhardy.
I think you should read what they say.
I have. It's arrogant nonsense, based on vastly incomplete information about what "alternate universe generation" producing "alternate universes" with "alternate physics" and "alternate life" might be possible.
The ones I have read are very well informed about other fields of science.
...none of which prepares them for the wild-ass speculations they make.
Nor do I know of any biologists or other scientists who can contradict them, or even try.
Then you haven't looked real carefully, this kind of nonsense gets frequently refuted.
Remember, we are not talking about conditions which are merely different in the way submarine hot springs are, or the surface of Mars is. We are talking about conceptual universes in which no matter is possible at all,
And how exactly do they determine what kind of matter is or is not possible in a "conceptual universe", when they don't even understand the workings of *our* universe well enough to have been able to predict, based on nothing but the values of the physical constants, whether life would have been possible in this one?
A "conceptual universe" is just someone using their imagination. And the conclusions they draw about it will be as accurate as those based on any complete fantasy.
or in which the Big Bang would already have reversed and collapsed, without leaving enough time for life to form.
...or in which other forces would result, totally unknown to us in this universe, which would have obviated that "problem".
"And how exactly do they determine what kind of matter is or is not possible in a "conceptual universe", when they don't even understand the workings of *our* universe well enough to have been able to predict, based on nothing but the values of the physical constants, whether life would have been possible in this one?"
I would say physicists today understand "the workings of our universe" pretty well. I wish I could lay hands on the refs which show how tiny changes in basic physical constants make the observed nature of matter impossible.
""basic variables"
The point is that some of these quantities are not variables at all. They are fixed at values which allow matter as we know it. Slight changes would change everything.
"Nor do I know of any biologists or other scientists who can contradict them, or even try.
Then you haven't looked real carefully, this kind of nonsense gets frequently refuted."
By whom? Biologists? (I suspect from your posting name that you are a biologist.) I'm not talking here about quibbling over thermal and chemical conditions which allow "life as we know it." I'm talking about physical constants which have to be within narrow ranges in order for the physical universe to exist, not just life.
I think physics and cosmology are much farther along than you imply. And I'm not talking about imaginary "alternate physics," but the sum of known physics at the present time, with all the known forces but gravity thought to have been integrated.
"And how exactly do they determine what kind of matter is or is not possible in a "conceptual universe", when they don't even understand the workings of *our* universe well enough to have been able to predict, based on nothing but the values of the physical constants, whether life would have been possible in this one?"
I think they assume that life requires certain light and heavy elements, certain temperature ranges, certain pressure ranges, etc., all of which are only found on planets somewhat like ours, which formed from heavy elements manufactured in supernovas, then accreted around newer stars. They believe that because all the life we know of requires such conditions. Do you have an alternate theory of suitable habitats or mechanisms for intelligent life? I'm sure the scientific community would be delighted to hear of it.
"A "conceptual universe" is just someone using their imagination."
No, it's people using the current state of science (physical laws, etc.) to calculate how matter and energy would be distributed. It's no more imaginary than the process by which biologists conclude that all organisms, including extinct ones which we cannot observe except as fossil hard parts, arose by natural selection and nothing else. It simply entails extrapolation and deduction.
In any case, there is a more fundamental problem with this sort of anthropic argument -- only a universe where some form of intelligence arises can be observed, because there is nobody to observe the other kind. When the rules are "heads I win, tails doesn't count", a string of heads is guaranteed even if the coin is heavily loaded in favor of tails.