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Two Objections By Neil Manson and a Response by Luke Barnes:
Another Objection from the paper by Weisberg: What's Fine-Tuning Got To Do With It? & A REPLY:
Another Undercutting Defeater for Evolutionary Debunking Arguments Against Moral Realism:
A Reply To Richard Swinburne's Argument That Moral Truths Are Analytically Necessary:
1) HOW ATHEISTS TAKE ALEXANDER VILENKIN OUT OF CONTEXT
2) 4 Cosmological Models that Unsuccessfully Try to Get Around the Borde-Guth-Vilenkin Theorem &
FOUR EXCEPTIONS (taken from Blackwell Companion to Natural Theology:
A) Infinite Contraction (deSitter Cosmology)
Involves an infinite contraction prior to the singularity, followed by our current expansion.
Problems: a) Assumes brute, acausal fine-tuning. b) The collapse becomes chaotic as it approaches the singularity which produces a pre-expansion start condition that is empirically known to be different than our actual "Big Bang." This problem plagues all attempts at a past-eternal timeline that seek to introduce a pre Big-Bang phase that "bounces" into the present expansion.
B) Asymptotically Static (Emergent Model Class)
Postulates an unstable initial state followed by an inflationary expansion where the initial state has an average expansion rate of zero once we factor in infinity even though our current universe is expanding.
Problems: a) Although in a pure non-quantum General theory of Relativity, worldlines can be traced to negative infinite time, we know that gravity is in fact a quantum phenomena, and that small fluctuations in the size of the universe are inevitable. This means that it is impossible for our universe to remain in balance from eternity past. Moreover, since our universe is not static, and a quantum fluctuation is in fact necessary for this two phase model to work, this very mechnism implies that the intial state is not past eternal. b) Even with the addition of loop quantum gravity, we know that any pertubation, or metastable potential will eventually cause the system to
escape the ESS state.
C) Infinite Cyclicity (Baum-Frampton "phantom bounce")
Imagines a contraction followed by a super-expansion fueled by ‘dark’ energy, with the universe breaking into a multiverse.
Problems: a) A truly cyclic universe has a problem with entropy increase: it should have reached thermodynamic equilibrium by now, but since our universe is not in such a state, this model of the universe is in error. Eventually the cycles get smaller as you go into the past such that there is an absolute beginning point.
b) Even with the addition of 'dark' energy to get around this problem: 1) the average expansion and contraction must be fine-tuned so that they exactly cancel one another out, 2) contracting space filled with quantum fields will have an "ergodic" property as the space shrinks; its fields become highly excited as one approaches the end of contraction and these fields will sponataneously produce a dense "fluid" of black holes leading toa condition called the "Black Crunch" for arbitrary states approaching full contraction; hence, this type of cyclicity will not work, 3) any matter or radiation will prevent cycling (during contraction), and there is a reasonably high probablity that spontaneous structure will eventually form as thermal fluctuations during contractions.
D) Aguirre-Gratton (Time Reversal at Singularity)
Postulates two mirror-image, inflationary expansions, where the arrows of time point away from the cosmological singularity.
Problems: a) this model denies the evolutionary continuity of the universe which is topologically prior to t, and our universe; the other side of de Sitter space is not our past; there is no connection or temporal relation whatsoever of our universe to the other reality; efforts to decontruct time thus fundamentally deny the evolutionary paradigm.
These highly speculative models are all either in contradiction to observational cosmology or else wind up implying the very beginning of the universe they sought to avert.