A. A. Milne

“ One way and another you get to know things about them."
"They must have a lot of time for thinking," said Celia, regarding my limpet with her head on one side. "Tell me, how do they know that there are no men in Mars?"
I sat up with a sigh.
"Celia, you do dodge about so. I have barely brought together and classified my array of facts about things in this world, when you've dashed up to another one. What is the connection between Mars and limpets? If there are any limpets on Mars they are freshwater ones. ”

“ Celia dropped into silence. Her next question showed that she had left the pool for a moment.
"Are there any people in Mars?" she asked.
"People down here say that there aren't. A man told me the other day that he knew this for a fact. On the other hand, people in Mars know for a fact that there isn't anybody on the Earth. ”

“ Well, I suppose you—er—study them. You sit down and—and watch them. Probably after dark they get up and do something. And of course, in any case, you can always dissect one and see what he's had for breakfast. ”