How Do We Know Fine-Tuning Is Improbable?
Fine-tuning arguments sometimes describe life-permitting constants as extraordinarily improbable. But calculating a probability requires more than identifying a narrow range of values. We also need some justified way of assigning probabilities to the possible values.
Why This Matters
This matters because a very narrow life-permitting range does not automatically tell us the probability that nature would produce a value inside that range.
If we do not know how the possible values are distributed, claims such as "one chance in an enormous number" may be much harder to justify than they first appear.
Response
This is an important caution. AVWJ should distinguish between a demonstrated sensitivity to parameter changes and a calculated probability that the observed value would occur.
Scientists can often model what happens when a parameter changes. That can establish that some regions of parameter space do not permit stars, stable matter, or other requirements. It does not automatically establish how likely nature was to select one region rather than another.
The fine-tuning question can therefore remain interesting even when a precise probability cannot responsibly be assigned.
Question That Remains
Can future fundamental theories provide a physically justified probability distribution for the constants and initial conditions, or is probability itself the wrong way to formulate parts of the fine-tuning problem?