man is the only animal which causes pain to others with no other object than causing pain…No animal ever torments another for the sake of tormenting: but man does so, and it is this which constitutes the diabolical nature which is far worse than the merely bestial

If we are the only animal with a sense of justice, it would clearly be because we also are about the only animal with a sense of cruelty.

Nothing but man was really cruel, vindictive, except perhaps the loathly cat.

[..] it has remained for man alone among all creatures to kill senselessly and wantonly for the mere pleasure of inflicting suffering and death.

He said that man’s heart was the only bad heart in the animal kingdom; that man was the only animal capable of feeling malice, envy, vindictiveness, revengefulness, hatred, selfishness, the only animal that loves drunkenness, almost the only animal that could endure personal uncleanliness and a filthy habitation, the sole animal in whom was fully developed the base instinct called patriotism, the sole animal that robs, persecutes, oppresses and kills members of his own tribe, the sole animal that steals and enslaves the members of any tribe.

Man is the only animal that deals in that atrocity of atrocities War. He is the only one that gathers his brethren about him and goes forth in cold blood and calm pulse to exterminate his kind. He is the only animal that for sordid wages will march out... and help to slaughter strangers of his own species who have done him no harm and with whom he has no quarrel.... And in the intervals between campaigns he washes the blood off his hands and works for the universal brotherhood of man with his mouth.

"People speak sometimes about the "bestial" cruelty of man, but that is terribly unjust and offensive to beasts, no animal could ever be so cruel as a man, so artfully, so artistically cruel."

If we are (almost) the only animal with a sense of justice, it is because we also are (almost) the only animal with a sense of cruelty.

Man is the only animal that laughs and weeps; for he is the only animal that is struck with the difference between what things are, and what they ought to be.

Men are the only animals that devote themselves, day in and day out, to making one another unhappy. It is an art like any other. Its virtuosi are called altruists.

El hombre es el único animal que ríe y llora; porque él es el único que conoce la diferencia entre las cosas que son y las que debieran ser.

Man, of all the animals, is probably the only one to regard himself as a great delicacy.

The cruel man is of misanthropic temperament, and is a man of moods, oscillating from quiet brooding to sudden explosions. If a man like this does not fight this unhappy provision of his soul during his youth, under no circumstances could he avoid becoming furious - and foolish. There are those who would leave it up to God, but to ensure justice on the earth, and not fob it off to the Divinity, it is mandatory that people know both virtue and its benefits, since the virtues lead to unity among them, not the war of all against all. Therefore, it is absolutely necessary to conserve them, and show that crime can only return misfortunes and destruction, including of the criminal himself. Who is the last victim of his crimes.

"Man is the cruelest animal," says Zarathustra. "When gazing at tragedies, bull-fights, crucifixations he hath hitherto felt happier than at any other time on Earth. And when he invented Hell...lo, Hell was his Heaven on Earth"; he could put up with suffering now, by contemplating the eternal punishment of his oppressors in the other world.