“Beyond a certain point - and that point is reached early - precision is what expressiveness depends on.”

Section 9 : Ethical Outlook
Founding Address (1876), Life and Destiny (1913)
Context: Theologians often say that faith must come first, and that morality must be deduced from faith. We say that morality must come first, and faith, to those whose nature fits them to entertain it, will come out of the experience of a deepened moral life as its richest, choicest fruit.
Precisely because moral culture is the aim, we cannot be content merely to lift the mass of mankind above the grosser forms of evil. We must try to advance the cause of humanity by developing in ourselves, as well as in others, a higher type of manhood and womanhood than the past has known.
To aid in the evolution of a new conscience, to inject living streams of moral force into the dry veins of materialistic communities is our aim.
We seek to come into touch with the ultimate power in things, the ultimate peace in things, which yet, in any literal sense, we know well that we cannot know. We seek to become morally certain — that is, certain for moral purposes — of what is beyond the reach of demonstration. But our moral optimism must include the darkest facts that pessimism can point to, include them and transcend them.

Source: Who Is Man? (1965), Ch. 5

Dissenting, Ullmann v. United States, 350 U.S. 422 (1956)
Judicial opinions

The Widow's Son

Source: The Blind Watchmaker (1986), Chapter 10 “The One True Tree of Life” (p. 261)

Source: Report to Greco

Playboy interview (1996)

Introduction<!-- pp. 3-4 -->
The Idea of Progress: An Inquiry Into Its Origin and Growth (1921)
Context: Science has been advancing without interruption during the last three of four hundred years; every new discovery has led to new problems and new methods of solution, and opened up new fields for exploration. Hitherto men of science have not been compelled to halt, they have always found ways to advance further. But what assurance have we that they will not come up against impassable barriers?... Take biology or astronomy. How can we be sure that some day progress may not come to a dead pause, not because knowledge is exhausted, but because our resources for investigation are exhausted... It is an assumption, which cannot be verified, that we shall not reach a point in our knowledge of nature beyond which the human intellect is unqualified to pass.