Why was the human race created? Or at least why wasn't something creditable created in place of it? God had His opportunity; He could have made a reputation. But no, He must commit this grotesque folly -- a lark which must have cost him a regret or two when He came to think it over & observe effects.
- Letter to William Dean Howells, 25 January 1900

As to the human race. There are many pretty and winning things about the human race. It is perhaps the poorest of all the inventions of all the gods but it has never suspected it once. There is nothing prettier than its naive and complacent appreciation of itself. It comes out frankly and proclaims without bashfulness or any sign of a blush that it is the noblest work of God. It has had a billion opportunities to know better, but all signs fail with this ass. I could say harsh things about it but I cannot bring myself to do it -- it is like hitting a child.
- Autobiography of Mark Twain, Volume 2, (2013)

There isn't any way to libel the human race.
- Mark Twain in Eruption

Etiquette requires us to admire the human race.
- More Maxims of Mark, Merle Johnson, 1927

What a man sees in the human race is merely himself in the deep and honest privacy of his own heart. Byron despised the race because he despised himself. I feel as Byron did, and for the same reason.
- marginalia written in Clemens's copy of Charles Greville's The Greville Memoirs: A Journal of the Reigns of King George IV and King William IV. The note is written near Greville's criticism of Lord Byron.

Such is the human race. Often it does seem such a pity that Noah and his party did not miss the boat.
- Christian Science

The human race consists of the damned and the ought-to-be damned.
- Notebook, 1898

The human race consists of the dangerously insane and such as are not.
- Mark Twain's Notebook, 1902-1903

Is the human race a joke? Was it devised and patched together in a dull time when there was nothing important to do?
- "The Czar's Soliloquy"

Damn these human beings; if I had invented them I would go hide my head in a bag.
- Letter to William Dean Howells, 1899

We all belong to the nasty stinking little human race, & of course it is not nice for God's beloved vermin to scoff at each other... Oh, we are a nasty little lot -- & to think there are people who would like to save us & continue us. It won't happen if I have any influence.
- Letter to William Dean Howells, 2 April 1899

In a book by Charles Darwin, Mark Twain had written: "Can any plausible excuse be furnished for the crime of creating the human race?"
- The New York Times, "Hartford Museum Purchases Barrels Full of Twain's Old Books," July 31, 1997

I have damaged my intellect trying to imagine why a man should want to invent a repeating clock, and how another man could be found to lust after it and buy it. The man who can guess these riddles is far on the way to guess why the human race was invented -- which is another riddle which tires me.
- Letter to Henry H. Rogers, 24 September 1894

That noble race which was made out of the excrement of the angels. If God has any sense of humor, He -- but no, He hasn't. He can make ridiculous things, up to the best of us, but He doesn't know they are ridiculous.
- Letter to Joseph Twichell, 4 November 1904

You can never find a Christian who has acquired this valuable knowledge, this saving knowledge, by any process but the everlasting and all-sufficient "people say." In all my seventy-two years and a half I have never come across such another ass as this human race is.
- Autobiography of Mark Twain, Vol. 3 (2015)