[Hans Blom, 951101b]
(Bill Powers (951031.1050 MST))
One more remark on this posting:
This makes probability into a causal agency. ... Probability can't
cause anything.
But SUBJECTIVE probability can. In a model-based ("predictive")
controller, an "idea" exists of what the result of a certain action
will be, modelled as e.g. x[k+1] := f (x[k], u[k]). Generate an
action u, and the predicted result will e.g. be b * u. The term b
might not be accurately known but also have an unknown component
(variance), so that when the action u is executed, any result between
bmax * u and bmin * u might be perceived. In a probabilistic model-
based controller, estimates of both b and its uncertainty exist. And
thus probabilistic numbers can be used when "computing" an action.
And in the case where several discrete actions (or action sequences)
might possibly provide a solution to a problem, the individual's
subjective probability of effectiveness of actions would provide a
solution to which action to choose preferentially: the one with the
highest (subjective) likelihood of success.
These subjective probabilities and likelihoods do not exist in the
outside world; they are properties ("knowledge") of the individual.
The "knowledge" of an individual might be completely incorrect or
uncertain, yet it will determine the individual's behavior.
This is how probability is a causal agency.
Greetings,
Hans