ABSTRACT
According to standard doctrine, arguments may be divided into two classes: deductive and non-deductive. A deductive argument purports that its premises are sufficient to establish the truth of its conclusion, and this will be the case if all the premises are true and the argument is formally valid. Judges, of course, give formally valid deductive arguments in justifying decisions on questions of law, but they also give arguments that in terms of logical structure have the form of non-deductive arguments, e.g., arguments by analogy. It is traditionally held that it is a feature of non-deductive arguments that their form is not sufficient to establish the truth of their conclusions even if all their premises are true: such arguments at best show only that the conclusions are more likely to be true than false. This, however, does not seem to be an adequate characterization of judicial arguments by analogy; for in supplying such an argument a judge presumes to have established the correctness, rather than the mere likelihood, of his conclusion of law on the basis of premises that he uses. This paper deals with the problem of whether this presumption is well founded. Let us begin with an example.
