# Fine-tuning argument

1. May 26, 2014

### stlukits

I am doing some work on the fine-tuning argument (FTA), basically

$$P(D|F\&B)>P(D|B)$$

where $D$ is the hypothesis that the physical constants were in some way designed (to make life possible, for example), $B$ is shared background information and $F$ is the observation that the physical constants are in some way fine-tuned to make life possible.

I am not a physicist (which is why I am asking for help here), but I assume that there are $n$ physical constants which could range over a continuum of values, so that $F$ could be characterized to be the observation of a vector $x=(x_{1},\ldots,x_{n})$ in $\mathbb{R}^{n}$ which belongs to a very small subset of $\mathbb{R}^{n}$, allowing life to develop.

Design hypotheses are usually confirmed when there is some kind of pattern, not only when a very unlikely event takes place. My question is: how can a single observation of a point in $\mathbb{R}^{n}$ constitute a pattern? It is true that something surprising is happening when the physical constants that are in place in this universe match the independently calculated physical constants that enable life (let's grant this point to advocates of FTA). The design hypothesis would only be confirmed, however, if the data are in some sense sequential such that a pattern can be discerned (for example a pattern with low Kolmogorov complexity). This does not appear to be the case here. There is only one observation here (this universe being the only specimen we can observe), and even though the observation may be surprising, it does not raise the probability of the design hypothesis.

But it doesn't seem right that only sequential data can be patterned. What about the architectural blueprint for a cathedral? There seem to be three different kinds of designs, physical designs (galaxies, snowflakes, molecular structures), biological designs (organisms), and mental designs (poems, blueprints, mathematical theorems). Darwin's genius was in finding a mechanism to show that biological designs need not have a designer. Is there an analogous idea corresponding to physical designs? Does it make any sense to speak of physical designs?

The last paragraph may be orthogonal philosophical musings. What I am interested to know from you is whether there is a possibly Bayesian way of showing that either FTA is plausible or, based as it is on a single observation, not plausible.

2. May 27, 2014

### Andrew Mason

I am not sure where you are going with this but you cannot answer these big questions with logic. You need evidence and a consistent theory based on evidence.

The laws of physics do not explain why the laws of physics are what they are. Mathematical logic tells you what follows from the laws. Statistical probability tells you how unlikely it is for certain physically possible structures to form naturally. A large enough mass of molten iron may have a high probability of forming a sphere and an infinitesimally small chance of forming a Ferrari by itself.

AM

3. May 27, 2014

### Staff: Mentor

There is no evidence to support this assumption nor any theory which proposes it, which is why fine-tuning is not a viable topic for PF.