“With regard now, first, to the argument drawn with such apparent force purely from the method of natural science, it will be plain to a more scrutinising reflexion, that shifting from the legitimate disregard of a supersensible Principle — a disregard in which the empirical method is entirely within its right — to the denial or the doubt of it because there is and can be no scientific evidence for it, is in fact an abuse of the scientific method, an unwarrantable extension of it to decisions lying by its own terms beyond its reach.”

Source: The Evolution of Civilizations (1961) (Second Edition 1979), Chapter 1, Scientific Method and the Social Sciences, p. 33

Masses Publishing Co. v. Patten (1917).
Judicial opinions
Context: Political agitation, by the passions it arouses or the convictions it engenders, may in fact stimulate men to the violation of the law. Detestation of existing policies is easily transformed into forcible resistance of the authority which puts them in execution, and it would be folly to disregard the causal relation between the two. Yet to assimilate agitation, legitimate as such, with direct incitement to violent resistance, is to disregard the tolerance of all methods of political agitation which in normal times is a safeguard of free government.

A.1, 184a.16 sqq, source: http://classics.mit.edu//Aristotle/physics.html, Book I, Part 1, Tr. R. P. Hardie, R. K. Gaye.
Physics

Die dem Satz vom Grunde nachgehende ist die vernünftige Betrachtungsart, welche im praktischen Leben, wie in der Wissenschaft, allein gilt und hilft: die vom Inhalt jenes Satzes wegsehende ist die geniale Betrachtungsart, welche in der Kunst allein gilt und hilft.
Die Welt als Wille und Vorstellung, Zweiter Band, Ergänzungen zum dritten Buch, para. 36 (1859)
The World as Will and Representation (1819; 1844; 1859)

"The Portuguese Discoveries and the Rise of Modern Science," 1983

Source: The Rainbow: From Myth to Mathematics (1959), p. 88

Introductory
The Grammar of Science (1900)

Great Books: The Foundation of a Liberal Education (1954)

Progress, Coexistence and Intellectual Freedom (1968)
Context: We regard as "scientific" a method based on deep analysis of facts, theories, and views, presupposing unprejudiced, unfearing open discussion and conclusions. The complexity and diversity of all the phenomena of modern life, the great possibilities and dangers linked with the scientific-technical revolution and with a number of social tendencies demand precisely such an approach, as has been acknowledged in a number of official statements.