ABSTRACT
Attempts to establish a logic of probability have been numerous, but to most of them there have been fatal objections. One of the causes of faulty theories has been failure to distinguish—or rather, determination to confound—essentially different concepts which, so far as usage goes, have an equal right to be called “probability”. I propose, in this Chapter, to make a preliminary exploration of these different concepts in a discursive manner, leaving to later Chapters the attempt to reach precise definitions.
