Detection is, or ought to be, an exact science, and should be treated in the same cold and unemotional manner.

…but it is better to learn wisdom late than never to learn it at all.

Everything comes in circles. [...] The old wheel turns, and the same spoke comes up. It's all been done before, and will be again.

What is the meaning of it, Watson? said Holmes solemnly as he laid down the paper. "What object is served by this circle of misery and violence and fear? It must tend to some end, or else our universe is ruled by chance, which is unthinkable. But what end? There is the great standing perennial problem to which human reason is as far from an answer as ever.

Anything seems commonplace, once explained.

It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.

There's a light in a woman's eyes that speaks louder than words.