"The examples of plausible reasoning collected in this book... may throw light upon a much agitated philosophical problem: the problem of induction. The crucial question is: Are there rules for induction? ...the question should be... treated... in closer touch with the practice of scientists. ...older writers, such as Euler and Laplace, clearly perceived... that the role of inductive evidence in mathematical investigation is similar to its role in physical research. ...so the door opens to investigating induction inductively."