“Nobody can think straight who does not work. Idleness warps the mind.”

American automaker Henry Ford (1863-1947) believed that work also helped people to think better. He wrote a much-quoted paragraph in his column, “Mr. Ford’s Page,” in the Dearborn (MI) Independent in 1919:
 
“And after work, the next duty is to think. Nobody can think straight who does not work. Idleness warps the mind. It is a wonder we do not hear more about that fact—that the practiced hand gives balance to the brain.”
     
 
Wikipedia: Henry Ford
Henry Ford (July 30, 1863 – April 7, 1947) was an American industrialist, the founder of the Ford Motor Company, and sponsor of the development of the assembly line technique of mass production. Ford did not invent the automobile, but he developed and manufactured the first automobile that many middle class Americans could afford to buy. His introduction of the Model T automobile revolutionized transportation and American industry. As owner of the Ford Motor Company, he became one of the richest and best-known people in the world. He is credited with “Fordism”: mass production of inexpensive goods coupled with high wages for workers. Ford had a global vision, with consumerism as the key to peace. His intense commitment to systematically lowering costs resulted in many technical and business innovations, including a franchise system that put dealerships throughout most of North America and in major cities on six continents. Ford left most of his vast wealth to the Ford Foundation and arranged for his family to control the company permanently.
   
9 February 1919, Evansville (IN) Courier, “What Henry Ford Says,” pg. 12, col. 4:
And after work, the next duty is to think. Nobody can think straight who does not work. Idleness warps the mind. It is a wonder we do not hear more about that fact—that the practiced hand gives balance to the brain.
 
Chronicling America
13 March 1919, Washington (DC) Times, pg. 20, col. 2:
Listen to Mr. Ford
His Page In His Newspaper Is Well Worth Reading

(...)
And after work, the next duty is to think. Nobody can think straight who does not work. Idleness warps the mind. It is a wonder we do not hear more about that fact—that the practiced hand gives balance to the brain.
 
Google Books
Ford Ideals:
Being a Selection from “Mr. Ford’s Page” in The Dearborn Independent

By Henry Ford
Dearborn, MI: The Dearborn Publishing Company
1922
Pg. 65 (“Prevention Is Better Than Sympathy”):
And after work, the next duty is to think. Nobody can think straight who does not work. Idleness warps the mind. It is a wonder we do not hear more about that fact—that the practiced hand gives balance to the brain.
 
Thinking which does not connect with constructive action becomes a disease; the man who has it sees crooked; his views are lopsided.
     
Google Books
The Forbes Scrapbook of Thoughts on the Business of Life
By Forbes magazine
New York, NY: Forbes
1950
Pg. 190:
Nobody can think straight who does not work. Idleness warps the mind. Thinking without constructive action becomes a disease. — Henry Ford
 
Google Books
“The Greatest Quotations of All-Time”
By Anthony St Peter
Xlibris Corporation (Xlibris.com)
2010
Pg. 330:
Nobody can think straight who does not work. Idleness warps the mind. Henry Ford