“When, in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.”

Introduction, Lesson I: Definition and Sphere of the Science.
Elementary Lessons on Logic (1870)

Quoted on Contemporary art, http://coolturamagazine.com/xabier-lezama-mitologia-vasca/, February 15, 2020.

Letter to General P.G.T. Beauregard (3 October 1865)
1860s

Source: Tristes Tropiques (1955), Ch. 1 : Setting Out, p. 17
Context: I hate travelling and explorers. Yet here I am proposing to tell the story of my expeditions. But how long it has taken me to make up my mind to do so! It is now fifteen years since I left Brazil for the last time and all during this period I have often planned to undertake the present work but on each occasion a sort of shame and repugnance prevented me from making a start. Why, I asked myself, should I give a detailed account of so many trivial circumstances and insignificant happenings? Adventure has no place in the anthropologists profession; it is merely one of those unavoidable drawbacks, which detract from his effective work through the incidental loss of weeks or months; there are hours of inaction when the informant is not available; periods of hunger, exhaustion, sickness perhaps; and always the thousand and one dreary tasks which eat away the days to no purpose and reduce dangerous living in the heart of the virgin forest to an imitation of military service … The fact that so much effort and expenditure has to be wasted on reaching the object of our studies bestows no value on that aspect of our profession, and should be seen rather as its negative side. The truths which we seek so far afield only become valid when we have separated them from this dross.

Theory of Knowledge
Gesammelte Mathematische Werke (1876)

Source: Chemistry as an Interesting Subject for the Philosophy of Science, 2001, p. 192

General Conclusions, Part I : Containing Considerations addressed to Unbelievers and especially to Mr. Gibbon
An History of the Corruptions of Christianity (1782)
Context: That miracles are things in themselves possible, must be allowed so long as it is evident that there is in nature a power equal to the working of them. And certainly the power, principle, or being, by whatever name it be denominated, which produced the universe, and established the laws of it, is fully equal to any occasional departures from them. The object and use of those miracles on which the christian religion is founded, is also maintained to be consonant to the object and use of the general system of nature, viz. the production of happiness. We have nothing, therefore to do, but to examine, by the known rules of estimating the value of testimony whether there be reason to think that such miracles have been wrought, or whether the evidence of Christianity, or of the christian history, does not stand upon as good ground as that of any other history whatever.

Source: The Martyrdom of Man (1872), Chapter IV, "Intellect"