From Arthur Conan Doyle’s The Adventure of the Blue Carbuncle. Brought to mind during a doctor’s appointment today where we learned our baby daughter is 50th percentile for weight, 70th for height, and 98th for head size.
“But you are joking. What can you gather from this old battered felt?”
“I can see nothing,” said I, handing it back to my friend.
“On the contrary, Watson, you can see everything. You fail, however, to reason from what you see. You are too timid in drawing your inferences.”
“Then, pray tell me what it is that you can infer from this hat?”
He picked it up and gazed at it in the peculiar introspective fashion which was characteristic of him. “It is perhaps less suggestive than it might have been,” he remarked, “and yet there are a few inferences which are very distinct, and a few others which represent at least a strong balance of probability. That the man was highly intellectual is of course obvious upon the face of it….
“I have no doubt that I am very stupid, but I must confess that I am unable to follow you. For example, how did you deduce that this man was intellectual?”
For answer Holmes clapped the hat upon his head. It came right over the forehead and settled upon the bridge of his nose. “It is a question of cubic capacity,” said he; “a man with so large a brain must have something in it.”