This is probably the most flattering blog post about any of my work ever. It’s nice when people a lot smarter than you enjoy your work.

thanks!

Zach

Sorry, but I am more adept at philosophical analysis than physics and not a cosmologist (can reply re L. Wittgenstein better than Ed Witten…) However, to answer your question:
…why the so-called anthropic principle has any significance beyond being a classic tautology?
A well put anthropic principle is not the tautology, that of course outcomes must be consistent with starting conditions (i.e., our being here and the original laws.) That doesn’t explain why there wasn’t any number of possible lifeless universes, without observers existing (whether anyone would be there to say so being rather irrelevant to most astute thinkers.) Hence, the real point is, the “horizontal” question: why a universe like this (favorable laws AND outcome regarding life) or not, rather than the phony “vertical” question, of the outcome (life) being consistent with the starting conditions/laws, which of course it would be.

The interesting thing is, as any reader of the Tippler and Barrow classic The Anthropic Cosmological Principleknows, that the range of suitable laws is very narrow indeed (like the required value of the fine structure constant.) Hence, why is “the universe” like that, if not “designed” for life? There are lots of avenues there, like multiple universes with different laws such that we find ourselves in one of the few that are suitable etc. However, once one can believe in multiple universes with “different laws”, then where does it end? The modal realists have made the cogent argument that “all logically possible” universes should “exist”, since no clear logical reason can be given for selection and reification of some and not others. Indeed, they make a cogent case that the idea of “existing” as some special material state other than the platonic mathematical world description is circular, indefinable, and not logically coherent – can you do it?

If so, then the problem is actually even worse, because then all possible worlds really means all possible descriptions. If so, one has a vanishing Bayesian probability of finding oneself in a world that continues to be lawful instead of one of the infinitely more that were like this up to this point and then begin to diverge. Why? Because of all the change to different laws and variations and distortions of laws that can be described, and indeed the entirety of what behavior can be described after that point which certainly includes a gigantic set of chaotic futures, etc.

Hence, I think there really needs to be a manager of some sort, to ensure placement in effect of observers like us in a world that really has laws, since logical possibility is just too inclusive. Think of that as you wish. (Not to mention, our having experiences etc., but that gets into consciousness issues and I am just making the argument relating to physical conditions and our being here.)

I think that I do no disservice to science when I say that the term “principle”, in context with Barrow and Tipler’s weak interpretation, is a careless misuse of terminology by a field that used to be so very careful about such wording.

A “cosmic selection principle” that relies on random probabilities to rationalize improbabilty is a selection effect, not a physics principle.

A physics principle says something fundamental about structure and dynamics, whereas, selection effects, do not. A cosmological principle says something fundamental about the structure and dynamics of the universe, but they also define theories of everything, because this explains the motivating physics for the observed constraints on the forces.

I wonder what theory of everything that the theory of evolution might dictate if the anthropic constraint on the forces includes a mechanism or thermodynamic function for Darwinian-like evolution, which preserves the second law by conserving energy through evolutionary leaps to higher orders of the same basic structure?

You know, kinda-following the hard-evidenced fact that we became more “entropically efficient” when we lept from apes to harness fire, and beyond…

You know, hard empirical stuff like that…

Too bad that science can’t even recognize the begged question.

Where were you when your fellow atheists were taking a dump on physics?

Isn’t it unlikely for me to be born there, rather than a large city like Los Angeles, Nanking, or Mexico City? Should I suppose that some cosmic selection principle has determined my unlikely birthplace?

[This dumb comment revised to comply with the dumb comment parsing.]

Strong interpretations aren’t tautological, because they include a “fundamental dynamical principle” that defines the structure of the universe from first principles.

Weak interpretaions are both, circular, and tautological, but there is no valid weak interpretation without the multiverse, because the weak features are not what is observed.

“People”, (like David Gross), say that the (weak) fact of our existence can’t be falsified, so the selection principle can’t be falsified, but ANY valid cosmological principle necessarily falsifies any possibilty for selection effects.

The fact that the ’main failure in 20 years’ to produce a fundamental dynamical principle in lieu of “anthropic selection”, *most apparently* and only indicates that the anthropic constraint must be strongly linked to any realistically plausible cosmological structure principle, so he has disassociated the dynamical structure principle that is being indicated by the only two relevant facts, while complaining about the solution that is *most apparently* being offered.

A Very Strong Anthropic Principle

And Lab Lemming, are you talking about this one?
http://www.nytimes.com/2006/02/24/science/24star.html?ex=1298437200&en=5a1593907c7dfe1e&ei=5090&partner=rssuserland&emc=rss
Or something else?

But speaking of boom, can any of you professional astronomers give us the lowdown on this super-duper nova reported in the New York Times? What was it, where was it, can we see it, what is the actual data, and where does it fit in the grand scheme of things?

So how does changing an arbitrary label blow up the universe?

Or is the genie just being really obtuse and changing the laws of physics so that an atom with 1-proton and 2-electrons is stable (which presumably makes it impossible for anything to exist)?

I’ve lurked here for the past few months. I really appreciate the opportunity to have something of a behind the scenes view of the professional cosmologist. Thanks
Aquariid (a frequently unnoticed meteor shower)