Avoiding Circularity in the Design Argument
The double counting objection argues that fine-tuning is a circular logic error. You observe that the universe permits life. You then define a creator as a being who specifically wants to create life. Finally, you claim that the existence of life is evidence that this creator exists. This is a failure, however, since you built your hypothesis with the very data you now intend to use to prove that hypothesis.
To avoid circularity, you need to show why the creator would take action based upon a premise independent of the state of the universe prior to taking action. The best explanation for this is found in the classical principle of bonum est diffusivum sui, or “goodness is diffusive of itself,” which states that by nature, goodness has an inherent tendency to share or express itself outside of its own existence.
If a creator is independently derived via metaphysics that if such a being were to exist, then it would possess all possible goodness (or more modestly, one who perceives it’s good), we can predict that such a being will likely create. You are not looking at the universe and working backward. Instead, you are looking at the definition of goodness and working forward. This provides the “prior” motivation required for a valid Bayesian update.
This principle, inspired from Plato, leads to a specific prediction: the “plenitude of being” or a hierarchy of existence. A perfectly good creator would not merely create one type of thing, like a single human or a single star. To reflect an infinite or unsurpassable source of goodness, the creation must manifest a wide spectrum of reality, from simple matter to complex rational minds. This is the Scala Naturae (the ladder of being).
This succession of elementary things through plants, animals, men and heavenly beings was referred to as the Great Chain of Being. This provided an explanatory mechanism regarding why the cosmos is filled with so many inanimate items along side relatively few living entities. Lower levels on the chain provide the basis upon which higher levels are possible.
This hierarchy explains the “fine-tuning” of entropy. For a physical universe to contain a hierarchy that includes rational life, it requires a “funnel” structure. High-level complexity, such as a conscious brain, requires an immense amount of low-entropy energy to function. This means a vast, mostly empty universe is not a sign of waste. It is the necessary physical support system for a high-tier point of conscious matter.
The scarcity of life becomes a feature of the design rather than a bug. In this model, life is the “apex” of a thermodynamic pyramid. You are no longer “fine-tuning” a god to fit the data. You are using an independent theory of value (goodness) to explain why the physical constants must be set to produce a tiered reality where life is rare, complex, and supported by a massive inanimate foundation.
The specificity penalty
When you are practicing good epistemology, you must evaluate evidence based on how well that evidence fits into what you believe is going to happen next, versus whether or not it matches what you already know. When you apply this to a Bayesian perspective, you need to figure out whether your hypothesis would cause you to expect the data you are seeing now differently than you did before you came up with that hypothesis. When you create your hypothesis so that it will exactly match what you already see, you do not gain any new knowledge. Instead, you merely give a new name to something you already knew.
A standard for intellectual honesty involves establishing your starting principles before you examine the specific details of a case. This mirrors the scientific method where you state a hypothesis and its predicted outcomes prior to running an experiment. When you apply this to philosophy, you must derive the attributes or motivations of a creator from metaphysical first principles. If your model of a creator is built only from the physical constants of this specific universe, your argument is circular.
Critics and proponents of fine-tuning find common ground on the necessity of independent grounding. Both sides agree that if a hypothesis is “hand-tailored” to the data, it loses its status as an explanation. Critics argue that theists often commit this error by adjusting the divine nature to suit whatever physical laws are discovered. Proponents who use the principle of self-diffusive goodness agree that such an adjustment is a mistake, which is why they seek to ground the argument in a theory of value that exists regardless of the physical state of the world.
Agreement also exists regarding the role of complexity in explanations. Critics point out that a designer who is as complex as the universe they explain does not simplify the problem. Proponents of a hierarchical “plenitude of being” model attempt to answer this by showing that a single simple principle (goodness) necessitates a wide range of complex effects. Both parties agree that an explanation must provide a reduction in the “information cost” of the system to be considered successful.
Finally, both sides recognize the importance of the “total evidence” rule. You cannot ignore parts of the data that seem inconvenient, such as the vast areas of the universe that do not support life. A successful argument must account for both the presence of life and the prevalence of inanimate matter. By using entropy as a tool to create a hierarchy, you address the data of the whole universe rather than isolating only the parts that seem to favor a specific conclusion.
When you use a Bayesian approach to creating a theory about a creator, every time you narrow down characteristics of the creator to fit what you see in the data, the prior probability of that particular creator drops. That is, a more general hypothesis (such as an immaterial mind created the universe), is more likely to be true than a very specific archetype (such as an immaterial mind who has a preference for carbon-based life and low entropy beginnings).
Bayesians say that each time you impose another characteristic on the nature of the creator you are narrowing down what that creator could be and thus you are making that specific version of the creator much less probable than all of the other versions of the creator. Therefore, when you are trying to provide a motivation for the existence of the universe, a motivation that is broad such as “goodness” provides better support than does a motivation that is very specific (i.e., “a love for life”). The reason for this is that goodness is a much broader and simpler concept that allows for the same level of complexity we see in the universe without requiring that the divine nature be specified enough to match the data we see in the universe.
The scarcity of life becomes a feature of the design. In this model, life is the “apex” of a thermodynamic pyramid. You are no longer “fine-tuning” a god to fit the data. You are using an independent theory of value (goodness) to explain why the physical constants produce a tiered reality where life is rare, complex, and supported by a massive inanimate foundation.