As a rule, the more bizarre a thing is, the less mysterious it proves to be. - Arthur Conan Doyle

The relations between us in those latter days were peculiar. He was a man of habits, narrow and concentrated habits, and I had become one of them. As an institution I was like the violin, the shag tobacco, the old black pipe, the index books, and others perhaps less excusable. When it was a case of active work and a comrade was needed upon whose nerve he could place some reliance, my role was obvious. But apart from this I had uses. I was a whetstone for his mind. I stimulated him. He liked to think aloud in my presence. His remarks could hardly be said to be made to me — many of them would have been as appropriately addressed to his bedstead — but none the less, having formed the habit, it had become in some way helpful that I should register and interject. If I irritated him by a certain methodical slowness in my mentality, that irritation served only to make his own flame-like intuitions and impressions flash up the more vividly and swiftly. Such was my humble role in our alliance.

Most people, if you describe a train of events to them will tell you what the result would be. They can put those events together in their minds, and argue from them that something will come to pass. There are few people, however, who, if you told them a result, would be able to evolve from their own inner consciousness what the steps were which led up to that result. This power is what I mean when I talk of reasoning backward, or analytically.

"It is cocaine," he said, "a seven-per-cent solution. Would you
care to try it?"
"No, indeed," I answered brusquely. "My constitution has not got
over the Afghan campaign yet. I cannot afford to throw any extra
strain upon it."
He smiled at my vehemence. "Perhaps you are right, Watson," he
said. "I suppose that its influence is physically a bad one. I find
it, however, so transcendently stimulating and clarifying to the
mind that its secondary action is a matter of small moment."