“Facts are more insistent than theories, and in the last resort it is the nature of things which determine the course of our actions.”

Les Faux Monnayeurs (1925), Pt. 3, ch. 16

J 65
Aphorisms (1765-1799), Notebook J (1789)
Context: A great speech is easy to learn by heart and a great poem even easier. How hard it would be to memorize as many words linked together senselessly, or a speech in a foreign tongue! Sense and understanding thus come to the aid of memory. Sense is order and order is in the last resort conformity with our nature. When we speak rationally we are only speaking in accordance with the nature of our being. That is why we devise genera and species in the case of plants and animals. The hypotheses we make belong here too: we are obliged to have them because otherwise we would unable to retain things... The question is, however, whether everything is legible to us. Certainly experiment and reflection enable us to introduce a significance into what is not legible, either to us or at all: thus we see faces or landscapes in the sand, though they are certainly not there. The introducion of symmetries belongs here too, silhouettes in inkblots, etc. Likewise the gradation we establish in the order of creatures: all this is not in the things but in us. In general we cannot remember too often that when we observe nature, and especially the ordering of nature, it is always ourselves alone we are observing.

Original: (it) Affidati sempre al potere delle tue azioni. Saranno loro a determinare il corso delle tue giornate.
Source: prevale.net

The Educational Theory of Immanuel Kant (1904)
Context: Man has his own inclinations and a natural will which, in his actions, by means of his free choice, he follows and directs. There can be nothing more dreadful than that the actions of one man should be subject to the will of another; hence no abhorrence can be more natural than that which a man has for slavery. And it is for this reason that a child cries and becomes embittered when he must do what others wish, when no one has taken the trouble to make it agreeable to him. He wants to be a man soon, so that he can do as he himself likes.

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 62

Source: The Worldly Philosophers (1953), Chapter VI, Karl Marx, p. 158

"The Past and Future of String Theory" in The Future of Theoretical Physics and Cosmology: Celebrating Stephen Hawking's Contributions to Physics (2003) ed. G.W. Gibbons, E.P.S. Shellard & S.J. Rankin

Lecture to the Royal Aeronautical Society (1913)

Introduction to Book 1, as quoted/translated by Edward Rosen, Nicholas Copernicus on the Revolutions (1978) ed. Jerzy Dobrzycki, Edward Rosen.
De revolutionibus orbium coelestium (1543)