“If we proceed in this manner, there should develop a dynamic philosophy which knows no restrictions of time or space.”
Essentials to Peace (1953)
Context: The points I have just discussed are, of course, no more than a very few suggestions in behalf of the cause of peace. I realize that they hold nothing of glittering or early promise, but there can be no substitute for effort in many fields. There must be effort of the spirit — to be magnanimous, to act in friendship, to strive to help rather than to hinder. There must be effort of analysis to seek out the causes of war and the factors which favor peace, and to study their application to the difficult problems which will beset our international intercourse. There must be material effort — to initiate and sustain those great undertakings, whether military or economic, on which world equilibrium will depend.
If we proceed in this manner, there should develop a dynamic philosophy which knows no restrictions of time or space. In America we have a creed which comes to us from the deep roots of the past. It springs from the convictions of the men and women of many lands who founded the nation and made it great. We share that creed with many of the nations of the Old World and the New with whom we are joined in the cause of peace.
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George Marshall 49
US military leader, Army Chief of Staff 1880–1959Related quotes

“Now the kind of philosophy under which we proceed in the whole and in the part is moral philosophy or ethics; because the whole was undertaken not for speculation but for practice.”
Genus vero philosophie, sub quo hic in toto et parte proceditur, est morale negotium, sive ethica; quia non ad speculandum, sed ad opus inventum est totum et pars.
Letter to Can Grande (Epistle XIII, 40), as translated by Charles Latham in A Translation of Dante's Eleven Letters (1891), Letter XI, §16, p. 199.
Epistolae (Letters)

Dijkstra (1968) " A Case against the GO TO Statement http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD215.PDF" cited in: Bill Curtis (1981) Tutorial, human factors in software development. p. 109.
1960s
'Excerpts from the Teaching of Hans Hofmann', p. 66
Search for the Real and Other Essays (1948)

“Time and space are modes by which we think and not conditions in which we live.”
Earliest source located that attributes this to Einstein is the 1975 book The Nature of Scientific Discovery: A Symposium Commemorating the 500th Anniversary of the Birth of Nicolaus Copernicus edited by Owen Gingerich, p. 585 http://books.google.com/books?id=Ub3gAAAAMAAJ&q=%22certainly+a+central%22#search_anchor. But long before that, the 1944 book Einstein: An Intimate Study of a Great Man by Dimitri Marianoff and Palma Wayne contains the following quote on p. 62: "But Einstein came along and took space and time out of the realm of stationary things and put them in the realm of relativity—giving the onlooker dominion over time and space, because time and space are modes by which we think and not conditions in which we live." It appears from the quote that the authors were giving their own description of Einstein's ideas, not quoting him.
Misattributed

Source: The Revolution of Nihilism: Warning to the West (1939), p. 253

Quoted in "The Power of the Space Club"
Source: [Paikowsky, Deganit, The Power of the Space Club, 2017, Cambridge University Press, 9781107194496, https://books.google.co.in/books?id=e9AoDwAAQBAJ&pg=PA157&lpg=PA157#v=onepage&q&f=false, 12 September 2019, en]