Ingersoll, Robert Green -- Lecture (1881-05-01) “The Great Infidels,” Booth’s Theater, New York

Dave — Fri, 28 Aug 2026 22:50:04 +0000

The general objection to the new is, that it differs somewhat from the old, and the fact that it does differ is urged as an argument against its truth.

Robert Green Ingersoll (1833–1899) American lawyer, freethinker, orator
Lecture (1881-05-01) “The Great Infidels,” Booth’s Theater, New York
(Source)

Feynman, Richard -- Speech (1955-11), “The Value of Science,” National Academy of Sciences Autumn Meeting, California Institute of Technology, Pasadena

Dave — Tue, 03 Mar 2026 22:31:53 +0000

If we want to solve a problem that we have never solved before, we must leave the door to the unknown ajar.

Richard Feynman (1918–1988) American physicist
Speech (1955-11), “The Value of Science,” National Academy of Sciences Autumn Meeting, California Institute of Technology, Pasadena
(Source)

Reprinted in What Do You Care What Other People Think? (1988).

Feyman used this general construction on multiple occasions, e.g., in a speech (1964-09), "What Is and What Should Be the Role of Scientific Culture in Modern Society," Galileo Symposium, Florence, Italy (reprinted in The Pleasure of Finding Things Out, ch. 4 (1999) [ed. Jeffrey Robbins]):

In order to make progress, one must leave the door to the unknown ajar -- ajar only.

WIST Quotations

Ingersoll, Robert Green -- Lecture (1881-05-01) “The Great Infidels,” Booth’s Theater, New York

Feynman, Richard -- Speech (1955-11), “The Value of Science,” National Academy of Sciences Autumn Meeting, California Institute of Technology, Pasadena