LOGIC

LOGIC . In the words of Petrus Hispanus, logic is both "ars artium et scientia scientiarum, ad omnium aliarum scientiarum methodorum principia viam habens." Roughly, we may take this to say, in modern terms, that logic concerns itself with the methods of correct statement and inference in all areas of inquiry whatsoever. Traditionally logic has divided into the study of deduction and of induction. The former has had an enormous development in the last hundred years or so, whereas the latter is still lagging behind, awaiting its coming of age.

Deductive logic does not dictate the principles or statements with which a given line of reasoning or inference starts; it takes over after these have been initially decided upon. Such principles or statements are decided upon, in turn, by direct insight, by revelation, by direct experience, by induction from instances, and so on. Deductive logic steps in only in the secondary capacity of directing the course of inferences once the so-called "premises" have been accepted or determined. The principles and rules of correct inference are stated in complete generality and hence are applicable to all kinds of subject matter. They are stated within a limited logical vocabulary—primarily that providing for the notions "not," "and," "or," "for all," "for some," and so on—to which the statements of any discipline must be brought into conformity by the use of suitable nonlogical constants providing for the given subject matter. Logic is thus indeed a kind of straitjacket that enforces correct statement and inference, just as moral norms enforce correct behavior and aesthetic norms enforce the beautiful or the artistically acceptable. In logic, however, there is less variation in the norms than in moral or aesthetic matters. Although many varieties of "deviant" logics have been invented, all of these turn out to be mere applications of the one standard logic. This is essentially the logic of Aristotle, brought up to date with the important contributions of DeMorgan, Boole, Peirce, Frege, Schröder, Whitehead and Russell, and Lesniewski.

Principles of logic have played a central role in theology throughout the long history of both, and each has influenced the other in significant ways. To be noted especially is the development, between roughly 1200 and 1500, of the Scholastic logic that aimed at providing the wherewithal for proofs of God's existence, especially those of Anselm, Thomas Aquinas, and Duns Scotus. In recent years, so-called process theology, stemming from the work of Whitehead, owes its origins to Whitehead's early work in logic, and much of the current discussion of the language of theology, especially in England, has been decisively influenced by the contemporary concern with the logic of natural language. In the East, especially in India, logic began to flourish in the first century ce within the confines of the methodology of theological and moral discussion and had a vigorous development that has persisted to the present day.

Logic, especially in its modern form, is a helpful adjunct to theology and should not be viewed with the fear that it will reduce the subject to a long list of sterile formulas. On the contrary, it should be viewed as an instrument that can help theology regain the high cognitive regality it once had as the queen of the sciences.

Bibliography

Bochenski, Joseph M. The Logic of Religion. New York, 1965.

Carnes, John. Axiomatics and Dogmatics. Oxford, 1982.

Martin, R. M. Primordiality, Science and Value. Albany, N.Y., 1980.

New Sources

Allen, James. Inference from Signs: Ancient Debates about the Nature of Evidence. New York, 2001.

Bowell, Tracy, and Gary Demp. Critical Thinking: A Concise Guide. London, 2001.

Falmagne, Rachel Joffe, and Marjorie Hass. Representing Reason: Feminist Theory and Formal Logic. Lanham, Md., 2002.

R. M. Martin (1987)

Revised Bibliography