Disclaimer: Dr. Who, it doesn't belong to me.
Martha leaned back in the Captain's chair and propped her feet on the TARDIS's console. The Doctor was on the other side, fiddling with something-or-other and babbling about his latest technological achievement. She endured his endless stream of talk for about five minutes before making a desperate attempt at a two-sided conversation.
"Er. Isn't that complimentary to the thingamabob you were messing with yesterday?"
The Doctor's head popped out from around the console, looking delightedly surprised. "You mean the Sub-Atomic Transcendentalist Quantum Half-Movement Lethargic Device?"
"Ummm, right. That one." Martha blinked helplessly in the face of the Doctor's techno-babble.
"Exactly right! That's very good, Martha Jones! Well, considering."
Martha narrowed her eyes suspiciously. "Considering what?"
"Well, you are human." The Doctor pointed out mildly.
"What has that got to do with anything?" His companion demanded in disbelief. "I use just as many scientific instruments as you do when I'm in the hospital, they just don't have names as ridiculous as yours!"
"Oh, come on, I didn't mean it like that. Time Lords are just superior to humans, is all—"
"Right, and that's not cocky at all—"
"—and there's no need to be offended." The Doctor plowed on, ignoring Martha's irritated jibe.
Martha was now openly glaring at the Doctor. "Name one thing that makes Time Lords better than humans."
"All right, then, I will." snapped the Doctor, coming around the console to stand in front of her. "Time Lords…Aha! Time Lords don't die. We regenerate. So while humans only live one lifetime, I live, well, bunches and bunches. I'm in my tenth body already, as a matter of fact."
Now this, in Martha's opinion, was something both interesting and worth pausing her argument for. "Do you still remember everything that happened in your previous bodies?"
"Sure do!" chirped the Doctor, smug in the knowledge that he had won their little fight. "When a Time Lord regenerates, they get a new body and personality, but keep all their old memories."
Suddenly, Martha could see a way of outsmarting the Doctor. She had never thought she would be grateful for that philosophy class in college, but now…
"So what you're telling me is, with the exception of your memories, when you regenerate you become a new person?"
"Yeah, that's about it." the Doctor beamed.
"So you're superior to humankind because you become a new person every now and again?"
"That's right." the TARDIS's resident Time Lord replied happily. "Now that we've got that out of the way, I've got some repairs to do—"
But before he could get back around the console to his awaiting doohickey, Martha called him back.
"Wait, wait. I just thought of this great riddle to tell you. Wanna hear?"
If there was one thing the Doctor couldn't resist, it was a riddle, especially when posed by a member of a species he was confident he was more intelligent than. "Sure," he agreed eagerly, "tell me about it."
"Okay," Martha started, "this is a riddle in several parts. Ready?" The dashing fellow in pinstripe suit nodded eagerly. "Okay then. Say you have a handful of pebbles. If you add one pebble or take one away, is the number the same?"
The Doctor analyzed her question, searching for tricks, and found none. "No, it's not," he conceded.
Martha nodded encouragingly. "Okay, next question. If you have a length of rope, and you add or subtract rope from it, is the length the same?"
The Doctor once again examined his companion's question and once again found no trickery. "No, the old length doesn't exist anymore."
Martha smirked in a way that made the Doctor feel very nervous. "That's right. Now, I want you to think the same way about the human race. Every human is constantly changing—we're either growing or diminishing. So technically, every second—no, every millisecond—no, every single little passage of a time unit—I am a different person with a different body and personality, but the same memories. So tell me, Doctor, who is the superior being—the Time Lord who changes body and personality every few years, or the human who changes body and personality faster than the mind can process?"
If Martha hadn't been a totally independent and empowered woman, she would have melted into apologies and hugs and cuddles at the look that sprouted on the Doctor's face.
Unfortunately for him, she was in fact independent and empowered, so she just gave a triumphant laugh.
"But but but—that's—that's—" The look of pitiful frustration on his face was downright hilarious to Martha, who was now shaking with the effort of not bursting into full laughter.
"That's not fair!" he whined finally, pouting with all the power of a nine-hundred-and some odd years-old man who has just been regenerated into a body with the adorable factor of a five-year-old.
Martha grinned. "Life's tough, get a helmet."
Then, at his further pout, "Well, I guess you'll just have to live with my superior intelligence."
"Why?" he demanded petulantly.
"Well, you are a Time Lord."