146

Logic 146

of deductive logic the doctrine of chances which has been called with little exaggeration the logic of the exact sciences.
This involves several difficult questions of which the two chief are on the one hand the foundation of the doctrine together with the nature of probability and on the other hand the admissibility of inverse probabilities.
Both of these are matters of practical importance to us all; for although few have occasion to make numerical computations of probabilites the use of the ideas and propositions of the calculies is most widely extended and to great advantage while at the sometimes even the greatest mathematicians have fallen into fatal practical errors both in the theory and in the application of it.
The first of two questions mentioned us by no means one to be settled at one blow.
A whole nest of fallacies is hidden in it.
This is why I cannot here in a few words approximately define my position so that a person acquainted with the state of discussion can get