“Everything that has been said, and every conclusion that has been tentatively put forward, is quite frankly speculative and uncertain. We have tried to discuss whether present-day science has anything to say on certain difficult questions, which are perhaps set for ever beyond the reach of human understanding. We cannot claim to have discerned more than a very faint glimmer of light at the best; perhaps it was wholly illusory, for certainly we had to strain our eyes very hard to see anything at all. So that our main contention can hardly be that the science of to-day has a pronouncement to make, perhaps it ought rather to be that science should leave off making pronouncements: the river of knowledge has too often turned back on itself.”
The closing sentences of the book, on p. 188 of Pelican Books 1938 reprint of 1931 2nd ed.
The Mysterious Universe (1930)
Help us to complete the source, original and additional information
James Jeans 54
British mathematician and astronomer 1877–1946Related quotes

“We come too late to say anything which has not been said already.”
Tout est dit, et l'on vient trop tard depuis plus de sept mille ans qu'il y a des hommes qui pensent.
Aphorism 1; Variant translation: Everything has been said, and we have come too late, now that men have been living and thinking for seven thousand years and more.
Les Caractères (1688), Des Ouvrages de l'Esprit

http://coldplaying.com/ultimate-ghost-stories-walkthrough-chris-martin/ source

Speech at the Albert Hall (4 December 1924), quoted in On England, and Other Addresses (1926), pp. 72-73.
1924

Fabian Essays in Socialism – The Basis of Socialism – Historic http://www.econlib.org/library/YPDBooks/Shaw/shwFS1.html#The%20Basis%20of%20Socialism,%20Historic,%20by%20Sidney%20Webb, The Development of the Democratic Ideal, I.1.1. Edited by George Bernard Shaw (1889)

Speech https://api.parliament.uk/historic-hansard/commons/1938/oct/03/prime-ministers-statement#S5CV0339P0_19381003_HOC_14 in the House of Commons (3 October 1938) against the Munich Agreement.
1930s

Source: The Wealth of Nations (1776), Book IV, Chapter VIII, p. 721.

Discours de réception de Louis Pasteur (1882)