"The Zanj say that God did not make them black to disfigure them; rather it is their environment that made them so. The best evidence of this is that there are black tribes among the Arabs, such as the Banu Sulaim bin Mansur, and that all the peoples settled in the Harra, besides the Banu Sulaim are black. These tribes take slaves from among the Ashban to mind their flocks and for irrigation work, manual labor, and domestic service, and their wives from among the Byzantines; and yet it takes less than three generations for the Harra to give them all the complexion of the Banu Sulaim. This Harra is such that the gazelles, ostriches, insects, wolves, foxes, sheep, asses, horses and birds that live there are all black. White and black are the results of environment, the natural properties of water and soil, distance from the sun, and intensity of heat. There is no question of metamorphosis, or of punishment, disfigurement or favor meted out by Allah. Besides, the land of the Banu Sulaim has much in common with the land of the Turks, where the camels, beasts of burden, and everything belonging to these people is similar in appearance: everything of theirs has a Turkish look."

"Everybody agrees that there is no people on earth in whom generosity is as universally well developed as the Zanj. These people have a natural talent for dancing to the rhythm of the tambourine, without needing to learn it. There are no better singers anywhere in the world, no people more polished and eloquent, and no people less given to insulting language. No other nation can surpass them in bodily strength and physical toughness. One of them will lift huge blocks and carry heavy loads that would be beyond the strength of most Bedouins or members of other races. They are courageous, energetic, and generous, which are the virtues of nobility, and also good-tempered and with little propensity to evil. They are always cheerful, smiling, and devoid of malice, which is a sign of noble character."

"A noble man need not pretend to be virtuous, any more than a well-spoken man feigns eloquence. When a man exaggerates his qualities it is because of something lacking in him; the bully gives himself airs because he is conscious of his weakness. Pride is ugly in all men … it is worse than cruelty, which is the worst kind of sins, and humility is better than clemency, which is the best of all good deeds."

"It is better to go skiing and think of God, than to go to church and think of sport."

"Let me tell you the secret of such so-called successes as there have been in my life, and here I believe I give you really good advice. It was to burn my boats and demolish my bridges behind me. Then one loses no time in looking behind, when one should have quite enough to do in looking ahead..."

"The difficult is what takes a little time; the impossible is what takes a little longer."

"The history of the human race is a continual struggle from darkness towards light. It is, therefore, to no purpose to discuss the use of knowledge; man wants to know, and when he ceases to do so, he is no longer man."

"(In 2019) more than 150 years ago, Alexander von Humboldt warned that “the restless activity of large communities of men gradually despoil the face of the Earth”."

"there is this poetry. There is this science. The farther along the way we go in each, the more clearly the relationship may be perceived, the more prodigal the gifts. The definitions of Western culture have, classically, separated these two disciplines. When Darwin wrote of Humboldt that he displayed the rare union between poetry and science, he set the man in a line of heroes of that meeting-place-a line which includes Lucretius and Goethe and Leonardo, but which for the last centuries has been obscured in the critical structure which insists that the forms of imagination are not only separate, but exclusive."

"The celebrated traveller, Baron Humboldt, calling on the President one day, was received into his cabinet. On taking up one of the public journals which lay upon the table, he was shocked to find its columns teeming with the most wanton abuse and licentious calumnies of the President. He threw it down with indignation, exclaiming, "Why do you not have the fellow hung who dares to write these abominable lies ?" The President smiled at the warmth of the Baron, and replied — "What! hang the guardians of the public morals? No sir, — rather would I protect the spirit of freedom which dictates even that degree of abuse. Put that paper into your pocket, my good friend, carry it with you to Europe, and when you hear any one doubt the reality of American freedom, show them that paper, and tell them where you found it." "But is it not shocking that virtuous characters should be defamed?" replied the Baron. "Let their actions refute such libels. Believe me," continued the President, "virtue is not long darkened by the clouds of calumny; and the temporary pain which it causes is infinitely overweighed by the safety it insures against degeneracy in the principles and conduct of public functionaries. When a man assumes a public trust, he should consider himself as public property.""

"That celebrated traveller Humboldt was profoundly impressed with the scientific value of a combined effort to be made by the observers of all nations, to obtain accurate measurements of the magnetism of the earth; and we owe it mainly to his enthusiasm for science... that not only private men of science, but the governments of most of the civilised nations... were induced to take part in the enterprise."

"The most powerful influence exercised by the Arabs on general natural physics was that directed to the advances of chemistry; a science for which this race created a new era.(...) Besides making laudatory mention of that which we owe to the natural science of the Arabs in both the terrestrial and celestial spheres, we must likewise allude to their contributions in separate paths of intellectual development to the general mass of mathematical science."

"From the remotest nebulæ and from the revolving double stars, we have descended to the minutest organisms of animal creation, whether manifested in the depths of ocean or on the surface of our globe, and to the delicate vegetable germs which clothe the naked declivity of the ice-crowned mountain summit; and here we have been able to arrange these phenomena according to partially known laws; but other laws of a more mysterious nature rule the higher spheres of the organic world, in which is comprised the human species in all its varied conformation, its creative intellectual power, and the languages to which it has given existence. A physical delineation of nature terminates at the point where the sphere of intellect begins, and a new world of mind is opened to our view. It marks the limit, but does not pass it."

"While we maintain the unity of the human species, we at the same time repel the depressing assumption of superior and inferior races of men. There are nations more susceptible of cultivation, more highly civilized, more enobled by mental cultivation than others, but none in themselves nobler than others. All are in like degree designed for freedom; a freedom which, in the ruder conditions of society, belongs only to the individual, but which, in social states enjoying political institutions, appertains as a right to the whole body of the community."

"The principal impulse by which I was directed was the earnest endeavor to comprehend the phenomena of physical objects in their general connection, and to represent nature as one great whole, moved and animated by internal forces. My intercourse with highly-gifted men early led me to discover that, without an earnest striving to attain to a knowledge of special branches of study, all attempts to give a grand and general view of the universe would be nothing more than a vain illusion. These special departments in the great domain of natural science are, moreover, capable of being reciprocally fructified by means of the appropriative forces by which they are endowed."

"In order to ameliorate without commotion new institutions must be made, as it were, to rise out of those which the barbarism of centuries has consecrated. It will one day seem incredible that until the year 1826 there existed no law in the Great Antilles to prevent the sale of young infants and their separation from their parents, or to prohibit the degrading custom of marking the negroes with a hot iron, merely to enable these human cattle to be more easily recognized."

"Our imagination is struck only by what is great; but the lover of natural philosophy should reflect equally on little things."

"The expression of vanity and self-love becomes less offensive, when it retains something of simplicity and frankness."

"One of the noblest characteristics which distinguish modern civilization from that of remoter times is, that it has enlarged the mass of our conceptions, rendered us more capable of perceiving the connection between the physical and intellectual world, and thrown a more general interest over objects which heretofore occupied only a few scientific men, because those objects were contemplated separately, and from a narrower point of view."

"Devoted from my earliest youth to the study of nature, feeling with enthusiasm the wild beauties of a country guarded by mountains and shaded by ancient forests, I experienced in my travels, enjoyments which have amply compensated for the privations inseparable from a laborious and often agitated life."

"Only what we have wrought into our character during life can we take away with us."