person1883-1964

C. I. Lewis

Disciplines:

Summary

American pragmatist philosopher who invented modern modal logic (as an alternative to Russell-Whitehead's extensional logic) and developed a pragmatist epistemology based on the given in experience and conceptual schemes.

Core Contribution

Modal logic: invented S1-S5 systems of strict implication — the foundation of modern modal logic. Conceptual pragmatism: knowledge is the interpretation of a given sensory element through a pragmatically adopted conceptual scheme; the choice of scheme is pragmatic. Mind and the World Order: the most systematic statement of conceptual pragmatism.

Key Spikes & Highlights

Invented modal logic to avoid the Lewis Carroll paradox (from a contradiction, anything follows in classical logic) by using strict implication — a conceptual innovation that generated the entire modern study of necessity and possibility.
Was Quine's dissertation supervisor — and Quine later attacked the very analytic-synthetic distinction that Lewis's pragmatism presupposed, making their relationship a hinge point in 20th century epistemology.

Notable Works & Achievements

A Survey of Symbolic Logic

Mind and the World Order

An Analysis of Knowledge and Valuation

Historical Influences

Immanuel Kant William James Josiah Royce

Intellectual Lineage

American Pragmatism Kantian Philosophy

Contemporaries & Peers

John Dewey Bertrand Russell

Minds Influenced

W. V. O. Quine Roderick Chisholm Nelson Goodman

Intellectual Posterity

Modal Logic Conceptual Pragmatism Analytic Philosophy

Discussing

C. I. Lewis

Ask anything about C. I. Lewis — their ideas, influences, contradictions, legacy.

person1883-1964

C. I. Lewis

Disciplines:

ethics

logic

epistemology

Summary

Core Contribution

Key Spikes & Highlights

Invented modal logic to avoid the Lewis Carroll paradox (from a contradiction, anything follows in classical logic) by using strict implication — a conceptual innovation that generated the entire modern study of necessity and possibility.
Was Quine's dissertation supervisor — and Quine later attacked the very analytic-synthetic distinction that Lewis's pragmatism presupposed, making their relationship a hinge point in 20th century epistemology.

Notable Works & Achievements

A Survey of Symbolic Logic

Mind and the World Order

An Analysis of Knowledge and Valuation

Historical Influences

Immanuel Kant William James Josiah Royce

Intellectual Lineage

American Pragmatism Kantian Philosophy

Contemporaries & Peers

John Dewey Bertrand Russell

Minds Influenced

W. V. O. Quine Roderick Chisholm Nelson Goodman

Intellectual Posterity

Modal Logic Conceptual Pragmatism Analytic Philosophy

Discussing

C. I. Lewis

Ask anything about C. I. Lewis — their ideas, influences, contradictions, legacy.