Refuting the argument from fine tuning

In my earlier posting about Antony Flew’s Introduction to God and Philosophy, I noted that Flew had identified the “argument from fine tuning” as a “development” which future authors in this area should take into account. In this post, I want to explain what this argument involves, and why it is completely devoid of merit.

The argument from fine tuning is a derivative of the argument from design. (It is also one of several theories that have been associated with the phrase “anthropic principle”, but since this term has been applied to various mutually contradictory theses, wise people will avoid it.) One of its chief proponents is the former astronomer Hugh Ross. A summary version of the argument runs as follows:

There are many fundamental parameters in physics which determines what kind of a universe this is. Examples include the Plank’s constant, the mass and charge of the electron, the gravitational force constant, the speed of light, and many others. It turns out that if some of these numbers are slightly different than their actual values, our universe would not be able to support life. It is virtually impossible that the universe came to have these correct parameters for life by chance, because so many of these numbers must all lie in such a small range of values. So it appears that the constants of the universe were fine-tuned for life. The being who did this fine-tuning must be God; without such a being, there would be virtually no chance that life could exist. *

At first glance, it is tempting to argue against this proposition on its own terms, by examining the actual values of cosmological and physical constants and calculating whether or not the proposition describes the circumstances accurately. The web site from which this quotation is drawn cites one such argument, and goes into great detail to refute it. However this is (mostly) beside the point, for the following reason:

Every intelligent species that observes the universe that it lives in will find that the constants of its physical and cosmological models of this universe appear to be fine-tuned to support its own life – even if these constants are radically different from those in another universe, such as ours. If the constants of a particular universe are such that life is not possible, there will simply be no species to observe this fact. And we have no a priori reason to say how many possible universes fall into each category, and therefore no basis for asserting how likely or unlikely life is.

Consider the following thought experiment. In another possible universe, the cosmological and physical constants are such that large dense bodies such as planets cannot form; instead, stars are surrunded by shells of gas. Stable patterns can form in this gas due to some resonance phenomenon, and over time self-replicating patterns emerge. Since this patterns can change, and gas resources are finite, Darwinian evolution will occur, and one may suppose that in time intelligence may arise. Such cloud-creatures might develop cosmology and physics, and may think to themselves, “How fortunate we are that the constants of the universe are so finely tuned. If they were slightly different, solid planetary bodies might form that would gravitationally disrupt our fragile forms; life as we know it would be impossible!”

The proponents of the argument emphasize the “fine” in “fine tuning”, but this seems unwarranted. In any universe, every system of cosmological and physical science devised by a sentient species will include a wide range of constants and other fundamental properties. Some of these will be such that the overall system is particularly sensitive to their values; for others, the precise values will be relatively unimportant. Chance alone will dictate that some of these constants will seem to be finely balanced. Since these properties are largely emergent and are likely to be contingent in ways that we do not understand today, this “balance” may well be completely illusory. **

So where does this leave us? Every intelligent life form in any universe will necessarily perceive a “fine tuned” situation, whether it is true or not. There is no reason to believe that there is only one type of universe that might support life, no way to observe those universes that do not, no way to assess the significance of particular constants. (Indeed the argument is consistent with the hypothesis that a malevolent designer is manipulating physical constants to reduce the probability of life!) The bottom line is that the argument is a bust. It purports to derive an ontological statement from a contigent epistemological argument, but the unquantifiable character of the argument renders it meaningless.


* I struck out the final sentence because it is such a grotesque non-sequitur that I’m sure no reasonable person would want to be associated with it.

** In his important new book A Different Universe – reinventing physics from the bottom down, the Nobel physicist Robert Laughlin makes the point that many of the “laws” of chemistry and physics are dramatically insensitive to precise numbers, pure samples, and other properties that we might expect to be important. Since we only know the large-scale properties of one universe – this one – we are on very shaky ground if we presume certain kinds of sensitivity.

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