“You see, but you do not observe.”

“I followed you.'I saw no one.'That is what you may expect to see when I follow you.”

“By George!" cried the inspector. "How did you ever see that?"Because I looked for it.”

“Watson: When do we start?Holmes: You are not coming.Watson: Then you are not going. I give you my word of honour - and I never broke it in my life - that I will take a cab straight to the police station and give you away unless you let me share this adventure with you.”

“Perchance you shall, fair sir," said Nigel, "for all that I have seen of you fills me with this desire to go further with you. It is in my mind that we might turn this thing to profit and to honour, for when Sir Robert has spoken to you, I am free to do with you as I will.”

“That any civilized human being in this nineteenth century should not be aware that the earth traveled 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 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 difficulty in laying his hands upon it. Now the skilful 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 most perfect order. It is a mistake to think that 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.”

“At the moment our human world is based on the suffering and destruction of millions of non-humans. To perceive this and to do something to change it in personal and public ways is to undergo a change of perception akin to a religious conversion. Nothing can ever be seen in quite the same way again because once you have admitted the terror and pain of other species you will, unless you resist conversion, be always aware of the endless permutations of suffering that support our society.”