Probability All The Way Up (Or No Probability At All)

Richard Jeffrey's radical probabilism (`probability all the way down') is augmented by the claim that probability cannot be turned into certainty, except by data that logically exclude all alternatives. This claim is illustrated in frequentist language by an infinite nesting of confidence levels, and in Bayesian language by means of Jeffrey's updating of odds

Probability All The Way Up

Richard Jeffrey's radical probabilism ('probability all the way down') is augmented by the claim that probability cannot be turned into certainty, except by data that logically exclude all alternatives. Once we start being uncertain, no amount of updating will free us from the treadmill of uncertainty. This claim is cast first in objectivist and then in subjectivist terms