This discussion recounts the development of several anthropological definitions of human nature. It then examines conclusions of studies in other disciplines that make possible a revised empirical definition of human nature and which have led to reexamination of paleoanthropological data classed as unimportant under the rubrics of precceding studies. Finally, this discussion appraises certain of these data, as they pertain to the question: “Do empirical evidences suggest that a human nature, as well as a human structure, may be the product of evolutionary processes ?”

The author discusses some difficulties involved in the application of “degree of confirmation” to the confirmation of lawlike-statements. An alternative analysis is proposed, which is based on interval estimation. It is argued that this analysis is superior to the criticized method, in that it is better able to show how instantial confirmations are inductively relevant to a law, and in that it requires fewer undesirable extra-logical assumptions.

This article consists in a critical examination of an argument which purports to prove that many scientific hypotheses held to be probable are actually certain. The argument rests on the assumption that since the nonphilosopher would say of many scientific hypotheses that they are certain and would deny that the best-established hypotheses are merely probable, philosophers who say that no scientific hypotheses are certain must be mistaken. Examination reveals that the argument fails to take account of the technical nature of the claim that even the best-established hypotheses are probable.

The methodology of the empirical sciences is treated from a set-theoretical point of view. Starting from Tarski's formulation of the methodology of the deductive sciences, a relation between terms, called degree of centrality, is introduced. Epistemic correlation, and therefore the notion of interpretative system, is defined using this relation.

Recent writings of Professor Frank raise basic questions concerning the nature of science and its relations to social, political, theological and metaphysical issues.

This paper concentrates on several of these questions. What determines the acceptance of an hypothesis in the sciences? Is it explanation of the facts and confirmation by experimentation or is it the capacity of a theory to guide human conduct? Professor Frank's espousal of the latter criterion raises the question of whether this criterion can clearly be applied. Equally important: it places on the scientist the responsibility of (a) reliably predicting the effects of a theory on human conduct and (b), deciding which effects ought to be achieved, assuming we could reliably achieve them. Another set of problems arises concerning the relation between scientific views and metaphysical, political and religious beliefs. Are the former relevant to the latter? If so, how? Does not scientific method at least involve the rejection of certain political and religious philosophies? We conclude that each and all of these difficulties could be relieved if not resolved by accepting a thoroughgoing empiricism.

There are three points which Professor Schlesinger makes in his criticism of my discussion of the principle of simplicity.

1. (1) He holds that the principles of simplicity and verifiability may in actual use contradict each other. The simpler hypothesis will be rejected, he maintains, if it leads to unverified consequences.

2. (2) He holds that it is legitimate to add auxiliary hypotheses to one's theory, if it is desired to allow, let us say, for the creation of the universe by a deity, or to exclude the possibility for all time of such events as a pail of water freezing on fire.

3. (3) He maintains with Bridgman that the cosmogonists' use of the simple notion that the same laws of nature hold throughout space-time leads to “perfectly hair-raising extrapolations” which a verificationist will reject.