Evidence · Case 08 · Science
Luke Barnes’s review of the fine-tuning literature
One exhibit from the free evidence repository at apologetics.pro.
Sources
- Luke A. Barnes, “The Fine-Tuning of the Universe for Intelligent Life,” Publications of the Astronomical Society of Australia, 2012. (opens in a new tab)
Luke A. Barnes, “The Fine-Tuning of the Universe for Intelligent Life,” Publications of the Astronomical Society of Australia, 2012.
Objections & responses
- Barnes is a Christian and an active advocate for the design argument. Isn’t presenting his review as a neutral technical survey misleading?
Barnes is a Christian, and that should be said. His review was published in a peer-reviewed astrophysics journal, and its documentation of the fine-tuning cases has been accepted by physicists who reject the design inference, including Sean Carroll, who debated him and granted that the constants are fine-tuned while disputing what follows. The phenomenon is accepted across the divide even where the interpretation is not, and Carroll’s concession is the cleanest evidence of that.
- Narrow range compared to what? The constants have no known probability distribution, so calling the life-permitting range small assumes a measure that physics doesn’t supply.
This is the normalizability problem, and it is the most important technical objection to fine-tuning. The reply from defenders such as Barnes and Robin Collins is that one can work with the range of values current theories treat as possible and show that the life-permitting subrange is tiny relative to it, and that for several constants (the cosmological constant especially) the comparison is to a natural scale set by the theory itself. Critics reply that a natural scale is not a probability. This is a real, unresolved debate among physicists and philosophers, and it is the specific dispute behind the phrase a minority of physicists dispute how the case is framed.
- The fine-tuning is for life as we know it. Different constants might permit different kinds of life, or kinds of complexity we can’t imagine.
Many fine-tuning cases are not about life specifically but about whether anything complex can exist at all. A universe with no stars, no stable atoms, or one that recollapses in a fraction of a second has no chemistry of any kind, and other kinds of life does not help there. For the cases that really are life-specific, the objection has force, and defenders of the argument usually concede it. The argument is strongest where it rests on the structural cases, and that is where it should be pressed.