Principles Of Deduction Research Articles

On Consensus

Two Phenomena Have Converged in recent years to account for the current interest among international lawyers in the concept of the “consensus” of states. The first is the recognition in jurisprudence that all law, and particularly the international legal system with its lack of centrally organized sanctions, is founded on inductively verifiable psychology and not in deductive principles purportedly derived from God, nature, or reason. If international law is nothing more or less than what states (national decisionmakers and their counsel) think it is, then do not particular rules of international law owe their existence and transmutations to the flow of international consensus?

Detachment, Probability, and Maximum Likelihood

However, what has been called lottery paradox shows that we cannot accept this rule if we also accept the usual principles of deductive logic. For it would allow us to infer of each ticket in a fair N ticket lottery that the ticket will lose; and standard principles of deduction would then allow us to infer that no ticket will win (although we know that one of them will win). The suggested rule, taken with standard deductive principles, would permit us to derive a contradiction from consistent and possible evidence. Philosophers have suggested at least four ways to deal with the lottery paradox. One view, associated with Savage, Carnap, Jeffrey, and others, denies that inductive inference ever permits detachment and says that inductive inference is an application of the deductive theory of probability. Some proponents of this view take probabilistic inference to be a method of ensuring consistent assignments of subjective probability or degrees of belief.' A second theory, of Kyburg's, takes high probability to warrant detachment but rejects the usual principles of deduction: we can infer of each

Logic in Practice

THIS very able little book goes a long way to prove that logic is a human science, and not merely a more or less coherent collection of dry and irrelevant dogmas. The grounds of our beliefs, the purpose of thinking, the importance of form, and the fundamental principles of deduction and induction are analysed and explained in a way that should make their understanding easy and interesting. What adds to the value of Dr. Stebbing s book is the choice of the examples, which should make nonsense of the frequent reproach that formal logic is an idle game. Logic in Practice. By Prof. L. Susan Stebbing. (Methuen's Monographs on Philosophy and Psychology.) Pp. ix + 113. (London: Methuen and Co., Ltd., 1934.) 2s. 6d. net.

Infectious diseases and social conditions

The brilliant successes of bacteriology at the end of the 19th century and at the beginning of the current century so overshadowed the purely epidemiological study of infectious diseases that the focus began to be mainly on the bacteriological resolution of questions of an essentially epidemiological nature (the question of transmission, spread and course of infectious diseases). Koch's triad was a purely deductive principle, and the emergence of infectious diseases was postulated by the existence of those or other, but necessarily specific pathogens-discovered, or, due to the imperfection of our technology, not yet discovered. But already in the first decade of the present century individual voices of infectious disease specialists who express doubt as to the correctness of a purely bacteriological approach to the solution of epidemiological questions began to be heard, and the time after the war, which gave a great number of observations of an almost experimental character and precision, made it think that epidemiology could have its own method and experience.