“It is impossible to conceive of many without one.”

Half-Truths and One-And-A-Half Truths (1976)

Si le grain ne meurt [If It Die] (1924), ch. III
Source: Autumn Leaves

"A hundred years of thinking about God" (1998)

Philosophiae Naturalis Principia Mathematica (1687), Scholium Generale (1713; 1726)
Context: But it is not to be conceived that mere mechanical causes could give birth to so many regular motions: since the Comets range over all parts of the heavens, in very eccentric orbits. For by that kind of motion they pass easily through the orbs of the Planets, and with great rapidity; and in their aphelions, where they move the slowest, and are detain'd the longest, they recede to the greatest distances from each other, and thence suffer the least disturbance from their mutual attractions.

Source: Building Entopia - 1975, Chapter 12, Metropolis, p. 171

Source: Globalization - A Basic Text (2010), Chapter 5, Neo-Liberalism and Neo-Marxian Alternatives, p. 110

Source: The Land

Source: How to Pay for the War (1940), Ch. 1 : The Character of the Problem

George A. Kelly, "Man's construction of his alternatives." Assessment of human motives (1958): 33-64.