“The enemy of the moment always represented absolute evil, and it followed that any past or future agreement with him was impossible.”

Re: Stalin is not a cool name for software http://groups.google.com/group/comp.lang.lisp/msg/428b1f0fb729d6c7 (Usenet article).
Usenet articles, Miscellaneous

" New Textbooks for the "New" Mathematics http://calteches.library.caltech.edu/2362/1/feynman.pdf", Engineering and Science volume 28, number 6 (March 1965) p. 9-15 at p. 14
Paraphrased as "Precise language is not the problem. Clear language is the problem."
Context: The real problem in speech is not precise language. The problem is clear language. The desire is to have the idea clearly communicated to the other person. It is only necessary to be precise when there is some doubt as to the meaning of a phrase, and then the precision should be put in the place where the doubt exists. It is really quite impossible to say anything with absolute precision, unless that thing is so abstracted from the real world as to not represent any real thing.Pure mathematics is just such an abstraction from the real world, and pure mathematics does have a special precise language for dealing with its own special and technical subjects. But this precise language is not precise in any sense if you deal with real objects of the world, and it is only pedantic and quite confusing to use it unless there are some special subtleties which have to be carefully distinguished.

Billy writing a letter to a newspaper describing the Tralfamadorians
Slaughterhouse-Five (1969)
Context: The most important thing I learned on Tralfamadore was that when a person dies he only appears to die. He is still very much alive in the past, so it is very silly for people to cry at his funeral. All moments, past, present and future, always have existed, always will exist. The Tralfamadorians can look at all the different moments just that way we can look at a stretch of the Rocky Mountains, for instance. They can see how permanent all the moments are, and they can look at any moment that interests them. It is just an illusion we have here on Earth that one moment follows another one, like beads on a string, and that once a moment is gone it is gone forever.
When a Tralfamadorian sees a corpse, all he thinks is that the dead person is in bad condition in the particular moment, but that the same person is just fine in plenty of other moments. Now, when I myself hear that somebody is dead, I simply shrug and say what the Tralfamadorians say about dead people, which is "So it goes."

To the conception of the imperishable, the immortal, we oppose, in art, that of becoming, the perishable, the transitory, and the ephemeral.
We Abjure Our Symbolist Masters..., from War, the World's Only Hygiene (1911-1915)
1910's

La philosophie triomphe aisément des maux passés et des maux à venir. Mais les maux présents triomphent d'elle.
Maxim 22. Compare: "This same philosophy is a good horse in the stable, but an arrant jade on a journey", Oliver Goldsmith, The Good-Natured Man, Act i.
Reflections; or Sentences and Moral Maxims (1665–1678)

Source: All Tomorrow's Parties‎ (2003), Ch. 4 : Formal Absences of Precious Things, p. 21

Variant: It is difficult to live in the present, pointless to live in the future and impossible to live in the past.
Source: Dune

The First Part, Chapter 15, p. 76 (Italics as per text)
Leviathan (1651)

“Passage,” p. 45
The Creator (2000), Sequence: “The Dream Chamber”