“A spider lowered itself, fathom by fathom, on a perilous length of thread and was suddenly transfixed in the path of a sunbeam and, for an instant, was a thing of radiant gold.”

Source: Science and Hypothesis (1901), Ch. V: Experiment and Geometry (1905) Tr. https://books.google.com/books?id=5nQSAAAAYAAJ George Bruce Halstead

Pupils at Sais (1799)
Context: No one, of a surety, wanders farther from the mark than he who fancies to himself that he already understands this marvellous Kingdom, and can, in few words, fathom its constitution, and everywhere find the right path. To no one, who has broken off, and made himself an Island, will insight rise of itself, nor even without toilsome effort. Only to children, or childlike men, who know not what they do, can this happen. Long, unwearied intercourse, free and wise Contemplation, attention to faint tokens and indications; an inward poet-life, practised senses, a simple and devout spirit: these are the essential requisites of a true Friend of Nature; without these no one can attain his wish.

Liquidation (2003)
Context: But I believe in writing — nothing else; just writing. Man may live like a worm, but he writes like a god. There was a time when that secret was known, but now it has been forgotten; the world is composed of disintegrating fragments, an incoherent dark chaos, sustained by writing alone. If you have a concept of the world, if you have not yet forgotten all that has happened, that you have a world at all, it is writing that has created that for you, and ceaselessly goes on creating it; Logos, the invisible spider’s thread that holds our lives together.

The Brothers Karamazov (1879–1880)

Ch 25 http://www.literature.org/authors/twain-mark/connecticut/chapter-25.html <br class="br">A Connecticut Yankee in King Arthur&#x27;s Court (1889)

Essay: "Put a lid on it" - p.203
Dress Your Family in Corduroy and Denim (2004)

1920s, Sidelights on Relativity (1922)

From a letter published in The Merry Heart : Reflections on Reading Writing, and the World of Books (1996).
Context: To ask an author who hopes to be a serious writer if his work is autobiographical is like asking a spider where he buys his thread. The spider gets his thread right out of his own guts, and that is where the author gets his writing.

2015, Remarks to the People of Africa (July 2015)
Context: I have to also say that Africa’s democratic progress is also at risk when leaders refuse to step aside when their terms end. […] When a leader tries to change the rules in the middle of the game just to stay in office, it risks instability and strife -- as we’ve seen in Burundi. And this is often just a first step down a perilous path. And sometimes you’ll hear leaders say, well, I'm the only person who can hold this nation together. If that's true, then that leader has failed to truly build their nation. […] Nobody should be president for life. And your country is better off if you have new blood and new ideas. I'm still a pretty young man, but I know that somebody with new energy and new insights will be good for my country. It will be good for yours, too, in some cases.