“Be not solitary, be not idle.”

Context: Writers may be solitary but they also tend to flock together: they like being solitary together. I knew a lot of writers in London and many of them were award-winning writers and many of them were award-winning, respectable writers. And the trouble with being an award-winning, respectable writer is that you probably are not making a living.
If you write one well-reviewed, well-respected, not bad selling, but not a bestseller list book every three years, which you sell for a whopping 30,000 pounds, that's still going to average out to 10,000 pounds a year and you will make more managing a McDonald's. With overtime you'd probably make more working in a McDonald's. So there were incredibly well-respected, award-winning senior writers who, to make ends meet, were writing film novelizations and TV novelizations under pen names that they were desperately embarrassed about and didn't want anybody to know about.

January magazine interview (2002)

In Search of Memory (2006)
Context: Cori Bargmann... has studied two variants of C. elegans... The only difference between the two is one amino acid in an otherwise shared receptor protein. Transferring the receptor from a social worm to a solitary worm makes the solitary worm social.

"The Jelly-Bean"
Quoted, Tales of the Jazz Age (1922)

Shadows on the Rock (1931), Book III, Ch. 5

Source: Mrs. Dalloway

From Nobel Lecture (2014)

The Sayings of the Wise (1555)