A/N: I was reviewing my notes for my intro to psychology class and I saw a blurb about deduction. It made me laugh thinking about Sherlock (and what John says is right, bother Conan Doyle), so I got an idea for a fic. Also, yes John did go to King's College for uni! It said so on his resume. Enjoy, and please review!

"What you do," followed by loud steps, "Isn't deduction."

"Sorry?" Sherlock glanced back. "Where are the groceries? Another row with the machine?"

A half laugh, half exasperated exhale was the response. "No. Never mind that. What you do," John repeated, pointing a finger at Sherlock. "Isn't deduction."

"Is that so?" Sherlock replied, raising an eyebrow slowly. "What is it I do, then? Pray tell, Doctor."

"Well," he said, walking forward and pacing around. "I was talking to this - to this psychiatrist-"

"Yours, by any chance? I'm sure we all know how effective she is."

"No, no- a mate from uni-"

"King's College."

"Yeah- wait, how did you know?"

"Mycroft's not the only one who has surveillance and connections - though, obviously, my powers of observations are far superior."

"Right, yeah... Anyway, um, this old friend of mine was telling me-"

"You don't have friends."

He stopped his pacing. "Wha- yes I do. I have - I have Mike Stamford - who you've met."

"I have Mike Stamford," Sherlock mimicked. "No you don't. Any and all relationships you have are strictly by necessity - and it's whom."

"I - Sarah - she's - she's - my - my -"

"Doesn't count, she's a colleague. I'm a flatmate. As I've said - necessity."

John sputtered in response. "I'm - I'm going to make tea."

"Do. I'm parched."

John sighed and went into the kitchen.

Not a minute later he was striding back determinedly. "Hold on, I'm not finished," he said indignantly. "Deduction - deduction is going from - err, what is it - general to - specific. For example, if - if I went to the kitchen, you could deduct that I'm making tea-"

"Yes, speaking of which, where is my tea?" interrupted Sherlock lazily.

John ignored him. "But induction is going from the specific to general, which is what you do. See, if I came with tea, you could induct that I went to the kitchen - or something of the sort. Yeah, I think that's it. Or is it the other way around..."

There was silence.

"So - erm, am I right?"

"Hm? Sure."

John laughed, pacing around again. "Oh, this is brilliant! I'm right. Sherlock's wrong! Oh, this is just brilliant."

"Do shut up John and don't be stupid. Induction hasn't such a good ring to it; it was a test."

He laughed harder. "Oh, was it?"

"Obviously. Congratulations." Sherlock continued, voice dripping with sarcasm. "Gold star."