And, as a result of this examination," the forked pink beard smiled down gently from above, "the specialists discovered that what you call the human … - William Tenn

I've always been a loner. With whatever help I can buy, I take care of myself. I'm not interested in any goal except the extra buck. First and last, I'm a businessman."
"Oh, stop it!" the dark man took a turn up and down the office angrily. "This is a planet-wide emergency. There are times when you can't be a businessman."
"I deny that. I can't conceive of such a time."
Braganza snorted. "You can't be a businessman if you're strapped to a huge pile of blazing faggots. You can't be a businessman if people's minds are so thoroughly controlled that they'll stop eating at their leader's command. You can't be a businessman, my slavering, acquisitive friend, if demand is so well in hand that it ceases to exist."
"That's impossible." Hebster had leaped to his feet. To his amazement, he heard his voice climbing up the scale to hysteria. "There's always demand. Always! The trick is to find what new form it's taken and then fill it!"
"Sorry. I didn't mean to make fun of your religion.

And there, right there, is the area in which science fiction leads the literary side of its life. It is the job of the science-fiction writer to take the utterly fantastic, if need be, and make it seem as real as a copy of today's tabloid newspaper folded to the sports section. To the extent that he succeeds in this he is a good science-fiction writer, and to the extent that he fails to make the story believable he is a bad one, be it ever so full of faster-than-light gimmicks and futuristic individuals with triple brains and mechanical genitalia.

But now he had to have another look. It might not be so bad the second time. “It’s always darkest,” he told himself with determined triteness, “before the dawn.” And then found himself involuntarily adding, “Except on days when there’s an eclipse.”