What is the difference between plausibility and probability, and can we argue for the former without the latter? [duplicate]

Question

If I want to argue that hypothesis 𝐴 is more plausible (i.e., more worthy of credence) than hypothesis 𝐵, I could frame this using Bayesian inference given some evidence 𝐸 by showing that 𝑃(𝐸∣𝐴)⋅𝑃(𝐴) > 𝑃(𝐸∣𝐵)⋅𝑃(𝐵).

There are, however, several points worth noting:

• This approach relies on probabilities, effectively reducing the concept of plausibility to that of probability.
• The comparison depends on prior probabilities 𝑃(𝐴) and 𝑃(𝐵), which can feel recursive because it seems to assume we already have an idea of which hypothesis seems more plausible to us before considering the evidence, but the whole point of the exercise is to calculate plausibility in the first place.
• Additionally, applying probabilities in certain contexts can seem problematic or out of place, particularly in domains where we lack the ability to develop statistics to validate whether the real world aligns with our probability estimates. For instance, when evaluating the plausibility of competing metaphysical worldviews (see related question), we lack a "metaphysical simulator" to generate frequencies for how often worldview 𝐴 versus 𝐵 might be true.

This raises the question: are there situations in which plausibility carries a meaning that cannot be fully captured by or reduced to the concept of probability? If so, how do philosophers suggest arguing for plausibility without relying on probabilities?

Or am I overthinking this, and plausibility and probability are essentially interchangeable concepts?

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Closely related questions:

• What is the difference between a probability and a possibility?
• Is plausibility more fundamental than probability?
• How does one “measure” the plausibility of theories with no direct evidence?

Answer 1

There is an entire section on the SEP where they discuss various different approaches to model uncertainty and inferences under certainty. In the mapping listed, probability is a form of plausibility relation. It is a way to try to capture what is plausible using mathematical figures. As such, plausibility is arguably more fundamental than probability.

This can be practically seen in the area of theory choice. Scientists regularly choose between theories by virtue of epistemic values such as explanatory scope, explanatory power, simplicity, etc. They do this without attaching Bayesian probabilities to different hypotheses. See this article here for more on this.