Proponents of Social Darwinism should note that the term was introduced in Europe in 1877. It is often attributed to Herbert Spencer who coined the term "Survival of the Fittest" Although Spencer was not an actual Social Darwinist, (he was a Liberal Utilitarian) he forever changed the interpretation of Darwin's work. Spencer was further bastardized by Richard Hofstadter in Social Darwinism in American Thought, 1860–1915 (1944). Charles Darwin's abhorrance of slavery was a significant motivation to explore the concept of a common human ancestry. Charles probably would have given both men a sound beating.
The Division of University Studies Honors the Bicentennial of Charles Darwin’s Birth February 12, 1809
Charles Darwin on the Brutality of Slavery
"I thank God, I shall never again visit a slave country. To this day, if I hear a distant scream, it recalls with painful vividness my feelings, when passing a house near Pernamabuco, I heard the most pitiful moans, and could not but suspect that some poor slave was being tortured, yet knew that I was as powerless as a child even to remonstrate. I suspected that these moans were from a tortured slave, for I was told that this was a case in another instance. Near Rio de Janeiro I lived opposite an old lady, who kept screws to crush the fingers of her female slaves. I have staid in a house were a young household mulatto, daily and hourly was reviled, beaten, and persecuted enough to break the spirit of the lowest animal. I have seen a boy, six or seven years old, struck thrice with a horse-whip (before I could interfere) on his naked head, for having handed me a glass that was not quite clean; I saw his father tremble at a mere glance from his master’s eye…
It is claimed that self-interest will prevent excessive cruelty; as if self-interest protected our domestic animals, which are far less likely than degraded slaves, to stir up the rage of their savage masters. It is an argument long since protested against with noble feeling, and strikingly exemplified by the illustrious Humboldt. It is often attempted to palliate slavery by comparing the state of slaves to our poorer countrymen: If the misery of the poor be caused not by the laws of nature, but by our institutions, great is our sin…"
"Those who look tenderly at the slave-owner, and with a cold heart at the slave, never seem to put themselves into the position of the latter; -- what a cheerless prospect, with not even a hope for change! Picture to yourself the chance, ever hanging over you, of your wife and your little children—those objects which nature urges even the slave to call his own—being torn from you and sold like beasts to the first bidder! And these deeds are done and palliated by men, who profess to love their neighbors as themselves, who believe in God, and pray His will be done on earth! It makes one’s blood boil, yet heart tremble, to think that we Englishmen and our American descendents, with their boastful cry of liberty, have been and are so guilty: but it is a consolation to reflect, that we at least have made a greater sacrifice, than ever made by any other nation to expiate our sin*."
From: Darwin, C., The Voyage of the Beagle, 1839, pp. 433-34 in the Meridian Version first published in 1996.
*Darwin is referring here to the British action in outlawing the Transatlantic Slave trade in 1807, the British naval squadron efforts in intercepting and capturing slave runners, and the abolition of slavery in the British Empire in 1833.