"His ignorance was as remarkable as his knowledge."

Who?

Of contemporary literature, philosophy and politics he appeared to know next to nothing. Upon my quoting Thomas Carlyle, he inquired in the naivest way who he might be and what he had done. My surprise reached a climax, however, when I found incidentally that he was ignorant of the Copernican Theory and of the composition of the Solar System. That any civilized human being in this nineteenth century should not be aware that the earth travelled round the sun appeared to me to be such an extraordinary fact that I could hardly realize it.

"You appear to be astonished," he said, smiling at my expression of surprise. "Now that I do know it I shall do my best to forget it."

"To forget it!"

"You see," he explained, "I consider that a man's brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things, so that he has a difficulty in laying his hands upon it. Now the skillful workman is very careful indeed as to what he takes into his brain-attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment, and all in the most perfect order. It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones."

"But the Solar System!" I protested.

"What the deuce is it to me?" he interrupted impatiently: "you say that we go round the sun. If we went round the moon it would not make a pennyworth of difference to me or to my work."

Just something I ran into when I Googled the phrase "mental furniture," which came up during the conversation excerpted in the previous post. We'd been talking about how people have opinions and beliefs that are like rooms that they've got arranged some way that they like or they're used to, and if you want to come in and say maybe the sofa would be better on the other side of the room, and they're not up for moving it over there to check your theory, well... you can understand how they feel.

They're happy enough with the rooms they've got. They feel comfortable. They can't be spending all their time moving furniture about, thinking about whether some piece earns the space it takes up, always ready to drag something ugly or useless out to the curb, and going shopping for the perfect new tables and chairs. They want to live in those rooms they've already furnished. Why can't you be a more pleasant guest?