
Source: Introduction to Systems Philosophy (1972), p. 44.
Letter to Husák
Source: Introduction to Systems Philosophy (1972), p. 44.
“Entropy is the price of structure”
Source: Order Out of Chaos: Man's New Dialogue with Nature (1984), p. 283-284.
Ninth Memoir. On Several Convenient Forms of the Fundamental Equations of the Mechanical Theory of Heat.
The Mechanical Theory of Heat (1867)
Source: The Nature of the Physical World (1928), Ch. 4 The Running-Down of the Universe
The State of the World 2010, public lecture in New York City, USA, (July 2010)
“How can the net amount of entropy of the universe be massively decreased?”
The Last Question (1956)
“Shared pain is lessened; shared joy, increased — thus do we refute entropy.”
"Callahan's Law", as expressed in The Callahan Chronicals (1996) [originally published as Callahan and Company (1988)], Part IV : Earth … and Beyond, "Post Toast", p. 388. On the back cover of Callahan's Legacy (1996) this is modified into "Shared pain is lessened; shared joy is increased (and bad puns are appreciated).