The Fine-Tuning of the Universe for Intelligent Life

Luke A. Barnes

Comments: 76 pages, 9 figures

http://arxiv.org/PS_cache/arxiv/pdf/1112/1112.4647v1.pdf

Subjects: History and Philosophy of Physics (physics.hist-ph); 

Cosmology and Extragalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

The fine-tuning of the universe for intelligent life 

has received a great deal of attention in recent years, 

both in the philosophical and scientific literature. 

The claim is that in the space of possible 

physical laws, parameters and initial conditions, 

the set that permits the evolution of intelligent life is very small. 

I present here a review of the scientific literature, 

outlining cases of fine-tuning in the classic works 

of Carter, Carr and Rees, and Barrow and Tipler, 

as well as more recent work. 

To sharpen the discussion, 

the role of the antagonist will be played 

by Victor Stenger's recent book 

The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us. 

Stenger claims that all known fine-tuning cases 

can be explained without the need for a multiverse. 

Many of Stenger's claims will be found to be highly problematic. 

We will touch on such issues as the logical necessity 

of the laws of nature; objectivity, invariance and symmetry; 

theoretical physics and possible universes; entropy in cosmology; 

cosmic inflation and initial conditions; galaxy formation; 

the cosmological constant; stars and their formation; 

the properties of elementary particles 

and their effect on chemistry and the macroscopic world; 

the origin of mass; grand unified theories; 

and the dimensionality of space and time. 

I also provide an assessment of the multiverse, 

noting the significant challenges that it must face. 

I do not attempt to defend any conclusion 

based on the fine-tuning of the universe for intelligent life. 

This paper can be viewed as a critique 

of Stenger's book, or read independently.