He [Professor Moriarty] is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city. He is a genius, a philosopher, an abstract thinker. He has a brain of the first order.

I have heard, Mr. Holmes, that you can see deeply into the manifold wickedness of the human heart.

Some facts should be suppressed, or, at least, a just sense of proportion should be observed in treating them.

Still, it is an error to argue in front of your data. You find yourself insensibly twisting them round to fit your theories.

Watson. Come at once if convenient. If inconvenient, come all the same.

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.

Of all ghosts the ghosts of our old loves are the worst.