Lewis, Clarence Irving (1883-1964)

Lewis, Clarence Irving (1883-1964)

C. I. Lewis, logician, epistemologist, value theorist, and systematic philosopher, was born in Stoneham, Massachusetts and educated at Harvard University (A.B. 1905; Ph.D. 1910). He taught at the University of California from 1911 to 1919 and at Harvard from 1920 until retirement in 1953. He gave the Carus lectures, Woodbridge lectures, and Powell lectures. He was appointed Edgar Pierce Professor of Philosophy at Harvard. Stanford University has a philosophy professorship in his name. Lewis spent his entire career working systematically toward a defense of value judgments and ethics as part of the rational enterprise; as he says in the Woodbridge Lectures, “In all the world and in all of life there is nothing more important to determine than what is right.”

Lewis’s early work was in logic and philosophy of logic. In 1918, he published The Survey of Symbolic Logic, a classic work on the history and development of modern extensional logic that challenged the extensional nature of the widely adopted logical system developed by Bertrand Russell and A. N. Whitehead in Principia Mathematica. In Principia, only simple subject-predicate statements describe the world; the truth of compound statements such as conditionals is merely a function of the truth-values of the component simple statements. Lewis would later argue that contrary-to-fact conditionals, such as “If you fuse hydrogen, you will generate energy,” are not truth-functional and can present causal truths that describe the world. Principia acknowledged only material implication, expressed by a material conditional extensionally relating antecedent and consequent; a conditional is contingently false if its antecedent is true and its consequent is false. Lewis contended we actually reason deductively using logical implication; a conditional whose true antecedent is an argument’s premise and whose false consequent is the argument’s conclusion instead is necessarily false. In his 1932 Symbolic Logic (with Langford), he worked out a modal approach to logic that incorporates necessity and that is intensional in that it depends on the meaning (versus truth-values) of premises and conclusion.

The modern empiricist tradition has had to account for the a priori character of math, logic, and metaphysics. The philosophy of logic from Boole through Principia tried to reduce mathematical truths to logical truths. Lewis’s account of the a priori therefore focused on logic and philosophy. Lewis had worked out several equally good systems of modal logic, convincing him that no logic therefore is true and that logic does not tell us about the world. The choice of which logic to apply turns on its use as a tool in reasoning that helps us act in the world. In Mind and the World-Order (1929), he held that a priori truths are in some sense analytic. He contended that philosophical truths tell us how we must experience the world but not about the world in itself. But both logical and philosophical a priori truths can tell us only about the logical or conceptual relationships holding between the concepts that we use to shape up experience. The mind imposes a conceptual scheme, ordered by a set of fundamental categories, on sensory data in order to produce an experience of the world. Contra Kant, though, this conceptual and categorial scheme is a function of which way of ordering belief we find works pragmatically in the area of human action that meets human needs. We could change even our basic categories and logical truths on pragmatic grounds. Lewis called this position “conceptualistic pragmatism.” These kinds of a priori truths constitute one kind of foundation in his system.

His Analysis of Knowledge and Valuation (1946) presented his account of empirical knowledge. One traditional problem with knowledge was how to avoid an infinite regress, since what justifies a knowledge claim must itself need justification, ad infinitum. A traditional strategy was to identify some self-justifying, regress-stopping foundation. Sense datum theorists such as Russell had contended that sense data constituted that foundation by being known infallibly. Lewis instead argued that any knowledge claim must be subject to epistemic appraisal as correct or incorrect and justified or unjustified, and since sense data cannot be incorrect, they do not constitute knowledge. But he held that knowledge is generated from this sensory given. This “given” is not conceptually delineated, and so does not even constitute a judgment, though it can be reported in “expressive” language. Nevertheless, it is the basis from which we form predictive judgments about sense data. These conceptually structured judgments take the form of contrary-to-fact conditionals: given some sensory data, if one were to act in a particular way, one would expect a particular experience. Lewis called these “terminating judgments;” since they can be conclusively verified within experience, they provide the certain knowledge that stops the regress. Judgments about physical objects are non-terminating and can be analyzed into an infinite number of terminating judgments. So, all empirical knowledge of objects rests on terminating judgments; this knowledge is only probable, since further terminating judgments could in principle falsify the non-terminating judgment.

Lewis was in the pragmatist tradition, holding that knowledge aims at helping us act, while action in turn is guided by choices and therefore valuations. His value theory accounts for empirical value knowledge roughly parallel with empirical factual knowledge. The value “given” is a feeling or emotion--including likes, dislikes, pain, satisfaction, dissatisfaction, and so forth. These can be reported in expressive language but are not in the form of judgments. They cannot be in error and so cannot be knowledge. But they do form the basis for predictive judgments about feelings: given sensory data, if one were to act in a particular way, one would feel a particular way. Actually feeling that way would verify the judgment, so these are terminating value judgments. They give rise to non-terminating judgments about the objective value of something. Empirical knowledge of objective value is only probable.

In The Ground and Nature of the Right (1955) and in Our Social Inheritance (1957), Lewis turns to ethics. The individual can reach knowledge about the good, but this does not address how to decide which “good” to pursue. Ethics is needed to help one order one’s judgments of the good and weigh them. Lewis argues that all areas of rational deliberation--including logic, epistemology, and ethics—are constrained by rational imperatives, such as “Be consistent.” Any attempt to deny such imperatives would employ those very imperatives, producing a “pragmatic contradiction”. Ethical imperatives have a social dimension, in contrast with prudential imperatives, which speak to what is better for one in the larger context of one’s life. Unfortunately, Lewis never finished his work in the area of ethics.

(Number of Words: 1089)

Selected Works:

A Survey of Symbolic Logic. Berkeley, Calif.: University of California Press, 1918.

Mind and the World-Order: An Outline of a Theory of Knowledge. New York: Charles Scribner’s Sons, 1929; reprinted New York: Dover Publications, Inc., 1956.

Lewis, C.I. and C. H. Langford. Symbolic Logic. New York: The Appleton-Century Company, 1932; reprinted New York: Dover Publications, 1951.

An Analysis of Knowledge and Valuation. The Paul Carus Lectures, Series 8, 1946. La Salle, La Salle, Ill: Open Court, 1946.

The Ground and Nature of the Right. The Woodbridge Lectures, V, 1954. New York: Columbia University Press, 1955.

Our Social Inheritance. The Mahlon Powell Lectures, 1956. Bloomington, Ind.: Indiana University Pres, 1957.

Lange, John, ed. Values and Imperatives, Studies in Ethics. Stanford, Calif: Stanford University Press, 1970.

Goheen, John D. and John L. Mothershead, Jr., eds. Collected Papers of Clarence Irving Lewis. Stanford, Calif: Stanford University Press, 1970.

------

References and Further Reading:

Firth, Roderick, and Brandt, R. B. “Commemorative Symposium on C. I. Lewis.” Journal of Philosophy 61 (1964): 545-570.

Flower, Elizabeth and Murphey, Murray G. A History of Philosophy in America. Volume II. New York: G. P. Putnam’s Sons, Capricorn Books, 1977.

Haack, Susan. “C. I. Lewis” In American Philosophy, edited by Marcus G. Singer, 215-238, Cambridge: Cambridge University Press, 1986.

Hartshorne. Charles. Creativity in American Philosophy. Albany, NY: SUNY Press, 1984.

Kuklick, Bruce. The Rise of American Philosophy. New Haven, Conn.: Yale University Press, 1977.

MacKinnon, Barbara, ed. American Philosophy: A Historical Anthology. Albany, NY: SUNY Press, 1985.

Murphey, Murray G. C.I. Lewis: The Last Great Pragmatist. Suny Series in Philosophy. Albany, NY: SUNY Press, 2005

Parry, William Tuthill. “In Memoriam: Clarence Irving Lewis (1883-1964).” Notre Dame Journal of Formal Logic, 11, no.2 (April, 1970): 129-140.

Reck, Andrew J. The New American Philosophers. Baton Rouge, La.: Louisiana State University Press, 1968.

Saydah, J. Roger. The Ethical Theory of Clarence Irving Lewis. Athens, Ohio: Ohio University Press, 1969.

Schilpp, Paul Arthur, ed. The Philosophy of C. I. Lewis. La Salle, Ill: Open Court, 1968.

Werkmeister, W. H. “C.I. Lewis: The Man and his Philosophy.” The Personalist 47, no.4 (October 1966): 475-83.

------

author of entry on Adams: Dr. Seth Holtzman, Assistant Professor of Philosophy, Catawba College

------