Risk perceptions were operationalized by asking participants if they worry about EVD ("yes" or "no") and how they perceive their
personal probability of acquiring EVD in the following 9 scenarios: at work, in public transport, in public places, at an airport in Germany, as a patient in a hospital in Germany, at a doctor's office in Germany, during travel to affected countries, by food imported from West African countries, or by other products originating in West Africa.
He took certain rules about "rational decision making" as axiomatic, and deduced
personal probability and Bayes rules from these.
On one meaning, logical omniscience requires that the personal probability function of the ideally rational Bayesian agent assign a probability to all of the propositions that can be formulated within her language.
However, the ideally rational Bayesian agent cannot add any hypotheses to the set of hypotheses covered by her personal probability function.
Although psychology is not involved in the
personal probability analysis, agents do embrace some typical attitude and understanding in making their choices.
as the
personal probability of an agent who has no foreknowledge but is perfectly apprised of A's history and the laws which govern Its evolution.
De Finetti believed that it was possible to reduce what people thought they were referring to, when they talked about objective probabilities, to
personal probability distributions which take into account known or believed causal factors present in the set-up, like a coin's mass distribution, a smoker's physical constitution and age, and so on (de Finetti [1931], discussed in Skyrms [1991]).
They say that when we observe E, we should increase the
personal probability we attach to H in proportion to our prior
personal probability for E, given H, and in inverse proportion to our prior
personal probability for E: that is, H should be favoured to the extent its acceptance would have increased our expectation of E.
Personalist Bayesians hold that the theory of
personal probability supplies the logical framework within which uncertain inferences from empirical data are made.
For if the probability of heads occurring is greater when the treatment is present tha when it is not, then, so Papineau claims, the
personal probability that T causally influences H must be 1.