귀납에 관한 굿맨의 역설

Abstract

Deductive logic is a “yes or no” affair; an argument is either deductively valid or it is not. But inductive strength is a matter of degree. Thus while deductive logic must clissfy argument as valid or not, inductive logic must measure inductive strength of argument. If constructing a system of scientific inductive logic were totally impossible, we would be left with an intellectual vacuum, which could not be filled by appeal to “experts.” For, to decide whether someone is an expert predictor or a charlatan, we must assess the evidence that his predictions will be correct. And to assess this evidence, we must appeal to the second level of scientific inductive logic. Any prediction whatsoever, we can find a regularity whose projection licenses that prediction. Of course, most of these regularities will be unprojectible. The point is that we need rules to eliminate those predictions based on unprojectible regularities. I shall illustrate this principle in three ways: (1) in an example that closely resembles Goodman’s “grue-bleen” paradox; (2) with reference to the extrapolation of curves on graphs, (3) continuing a sequence of numbers. The knowledge gained from this discussion will then be applied to a reexamination of the principle of the uniformity of nature. The problem of constructing a system of scientific inductive logic will not be solved until the new riddle of induction and other problems have been solved. Although these solutions have not yet been found, there have been developments in the history of inductive logic which constitute progress towards a system.