The Nature and Limits of Logic

THE NATURE AND LIMITS OF LOGIC LGIC, as logic, does not investigate its own nature. Epistemology does this for logic. However, there is no one for whom the epistemological knowledge of the nature and scope of logic is more significant than for the man who happens to be a logician. Yet it is clear from an examination of our treatises and textbooks in logic that the men who author them disagree, sometimes rather significantly, on the epistemological character of logic. In the face of sometimes contradictory opinions about the nature of logic, it is clear that some of our logicians rather thoroughly misevaluate the significance of logic. Because logic is universally and necessarily propaedeutic to any scientific effort, it is not surprising that this misunderstanding on the nature of logic has serious consequences for all the academic disciplines. It is easy to allow more to logic than logic deserves, and the history of philosophy yields more than one example of over-extended logicism. It is easy too, in reaction to this, to allow less to logic than logic deserves. Thus some would make of logic a highly restricted instrument of the intellect for a very limited area of scientific discourse. In truth, logic is not a universal science embracing all other sciences (or any other science) either as integral or as subjective parts, and yet it remains universally an instrument of the reason for all scientific discourse. The intention of this paper is to initiate an investigation into the nature of logic which will make these points clear. This study will not be exhaustive, and yet it will be developed in the light of those distinctions in terms of which any exhaustive study should be made. This paper is at best a preliminary work, yet it is determinately in conflict with many current notions about the nature and limits of logic. . The occasion for this paper is the widespread disagreement on the nature and importance of logic. The immediate inspira47 48 EDWARD D. SIMMONS tion for it is a footnote suggested by the translators of The Material Logic of John of St. Thomas.1 The footnote arises in the context of a discussion on the speculative, but " useful," character of logic. In the footnote the translators broaden the discussion and suggest "that the ideal noetic treatment (of logic) would correlate these four frequently made distinctions and divisions within logic: science and art, doctrinal and in use, formal and material, and dialectical and judicative or demonstrative." In our opinion, these are the fundamental distinctions in terms of which logic must be epistemologically understood. This paper will attempt to meet the challenge implicit in the footnote just quoted. It will be an attempt to correlate these distinctions in order to lay at least the groundwork of an adequate investigation into the nature of logic. Logic is both an art and a science. It is a strange kind of art, and it is a unique type of science. It is an art without being practical, and it is a science which is speculative, despite the fact that its value lies only in its use. And it is one discipline which is simultaneously both an art and a science. It seems that almost every textbook in logic distinguishes between the art of logic and the science of logic. But not all of them agree precisely on the character of logic as an art and logic as a science. To begin with, some would allow logic to be treated either as a science or as an art, despite the fact that logic is indivisibly art and science. Further, in most , 1 The Material Logic of John of St. Thomas, translated by Yves R. Simon, John J. Glanville, and G. Donald Hollenhorst (Chicago, 1955), pp. 598-594, note 85. Although it is this particular footnote which has proximately inspired this essay, we readily and gratefully acknowledge a larger debt both to John of St. Thomas and to his translators. Perhaps the most helpful primary source for this study has been John's analysis of the nature of logic in. the first two questions of the second part of his Ara Logica. Certainly nothing could have been...