Der Glaube an eine vom wahrnehmenden Subjekt unabhängige Außenwelt liegt aller Naturwissenschaft zugrunde.
First sentence of "Maxwells Einfluss auf die Entwicklung der Auffassung des Physikalisch-Realen". Manuscript at the Hebrew University Jerusalem alberteinstein.info http://alberteinstein.info/vufind1/Digital/EAR000034102#page/1/mode/2up
From "Maxwell's Influence on the Evolution of the Idea of Physical Reality," 1931. Available in Einstein Archives: 65-382
1930s
Albert Einstein: Quotes about the world (page 3)
Albert Einstein was German-born physicist and founder of the theory of relativity. Explore interesting quotes on world.Source: Attributed in posthumous publications, Einstein and the Poet (1983), p. 139
"Only Then Shall We Find Courage", New York Times Magazine (23 June 1946).
1940s
Letter to an atheist (24 March 1954), p. 43
Attributed in posthumous publications, Albert Einstein: The Human Side (1979)
Source: Attributed in posthumous publications, Einstein and the Poet (1983), p. 16
1920s, Viereck interview (1929)
1940s, "Autobiographical Notes" (1949)
debunked in 2014
Misattributed
There is no indication that Einstein said this. According to Quote Investigator, the earliest publication of a quote similar was in a collection of articles about manufacturing in 1966, when an employee of the Stainless Processing Company wrote a piece titled "The Manufacturing Manager's Skills." The article attributed the quote to an unnamed professor at Yale, by saying, "If I had only one hour to solve a problem, I would spend up to two-thirds of that hour in attempting to define what the problem is." (See, 1966, The Manufacturing Man and His Job by Robert E. Finley and Henry R. Ziobro, "The Manufacturing Manager's Skills" by William H. Markle (Vice President, Stainless Processing Company, Chicago, Illinois), Start Page 15, Quote Page 18, Published by American Management Association, Inc., New York. Verified on paper). https://quoteinvestigator.com/2014/05/22/solve/
Disputed
Variant: If I had an hour to solve a problem I'd spend 55 minutes thinking about the problem and 5 minutes thinking about solutions.
Source: (October 15, 1953) as quoted by Johanna Fantova in Conversations with Einstein https://ysfine.com/einstein/fantova/fantova.html