“But people themselves alter so much, that there is something new to be observed in them for ever.”

Variant: The modern age did not so much invent new forms of migration as alter drastically the means and conditions of the old forms
Source: Europe on the Move: War and Population Changes, 1917-1947, 1948, p. 96 as cited in: Sarah Collinson (1999) Globalisation and the dynamics of international migration implications for the refugee regime http://www.unhcr.org/refworld/pdfid/4ff59b852.pdf. May 1999. p. 1

Source: A Brief History of Time (1988), Ch. 1
Context: Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.

Tradition and the Individual Talent (1919)
Context: What happens when a new work of art is created, is something that happens simultaneously to all the works of art which preceded it. The existing monuments form an ideal order among themselves, which is modified by the introduction of the new (the really new) work of art among them. The existing order is complete before the new work arrives; for order to persist after the supervention of novelty, the whole existing order must be, if ever so slightly, altered; and so the relations, proportions, values of each work of art toward the whole are readjusted; and this is conformity between the old and the new.

Source: Law and Authority (1886), I
Context: In existing States a fresh law is looked upon as a remedy for evil. Instead of themselves altering what is bad, people begin by demanding a law to alter it. … In short, a law everywhere and for everything! A law about fashions, a law about mad dogs, a law about virtue, a law to put a stop to all the vices and all the evils which result from human indolence and cowardice.
We are so perverted by an education which from infancy seeks to kill in us the spirit of revolt, and to develop that of submission to authority; we are so perverted by this existence under the ferrule of a law, which regulates every event in life — our birth, our education, our development, our love, our friendship — that, if this state of things continues, we shall lose all initiative, all habit of thinking for ourselves. Our society seems no longer able to understand that it is possible to exist otherwise than under the reign of law, elaborated by a representative government and administered by a handful of rulers. And even when it has gone so far as to emancipate itself from the thralldom, its first care has been to reconstitute it immediately. "The Year I of Liberty" has never lasted more than a day, for after proclaiming it men put themselves the very next morning under the yoke of law and authority.

Volume 3, Ch. 4
Fiction, The Book of the Long Sun (1993–1996)

Flipped (2001)

[The Guardian, 2008-09-04, A fetishistic approach to security is a perverse way to keep us safe, http://www.guardian.co.uk/technology/2008/sep/04/terrorism.terrorismandtravel, Schneier, Bruce, 2012-08-01]
Human perception of reality, risk and terrorism

Preface to the Revised Edition (October, 1906)
The Evolution of Modern Capitalism: A Study of Machine Production (1906)