Gravity and the Multi-verse?

[Apathia]

Let me recommend Lisa Randall's Warped Passages again. It gives a very clear exposition for the layperson and is not woo-woo.
Experiments with the LHC will impact many of the models she explains and raise more questions than are answered.

Let me parse the woo thing this way:

Tacyons as theoretical particles in some models of Theoretical Physics:
Science

Tacyons used to send a message back to the year 1965:
Science Fiction (Timescape by Gregory Benford)

Q-Link pendants enhancing qi by the emmision of tacyons:
Disgusting Woo-woo!

 

[AmateurScientist]

So we are left with the following explanations, either the standard models for cosmology and elementary particle phyiscs are incorrect, the models are correct but there is an underlying unifying theory which links the seemingly unrelated parameters together, the models are correct and our universe exists as it does solely as a result of a vanishingly small probabilistic outcome, the models are correct, and the vanishingly small probabilistic outcome is accounted for through a tremendous repetition of initial conditions. Of all those explanations, whilst all are rather unsatisfactory, the least unsatisfactory one, based on that which we currently know, would appear to be the tremendous repetition of inital conditions.

I find the latter to be by far the most satisfactory possible explanation. It would seem analogous to the evolution of life (not abiogenesis, but the evolution of the various forms) through multiple mutations over successive generations. Eventually, one particular branch led to us.

I don't see why the tremenous repetition of initial conditions on a cosmic scale is any less probable, any less satisfactory, or any less pleasing aesthetically than having the conditions which have led to our own existence as humans arise (the anthropic principle itself). Remember, we are dealing with the issue on a cosmic scale, with nearly infinite possibilities and an infinite series of attempts (assuming that that is how our own particular universe caming into being, rather than being the only possible universe and the only time a universe "tried" to spring into existence).

AS

 

[andyandy]

I find the latter to be by far the most satisfactory possible explanation. It would seem analogous to the evolution of life (not abiogenesis, but the evolution of the various forms) through multiple mutations over successive generations. Eventually, one particular branch led to us.

I don't see why the tremenous repetition of initial conditions on a cosmic scale is any less probable, any less satisfactory, or any less pleasing aesthetically than having the conditions which have led to our own existence as humans arise (the anthropic principle itself). Remember, we are dealing with the issue on a cosmic scale, with nearly infinite possibilities and an infinite series of attempts (assuming that that is how our own particular universe caming into being, rather than being the only possible universe and the only time a universe "tried" to spring into existence).

AS

i think we're in general agreement then. I find the theory of tremendous repitions the least unsatisfactory - but unsatisfactory nonetheless because it could ultimately be non-falsifiable.......
We may however be using different understandings of the
term "anthropic." The theory does not as i understand it make any anthropocentric claims - indeed the basic premise generally used with regards to inflationary cosmology and string theory is;

a) There exists a very large ensemble of universe M which are completely or almost completely causally disjoint regions of spacetime within which the parameters of the standard model of physics and cosmology differ.

b) The distribition of parameters in M is random (in some measure) and these parameters within our own universe are rare.

*this definition from Smolin [who goes on to critique this model]
http://arxiv.org/PS_cache/hep-th/pdf/0407/0407213.pdf