Chapter Text
FIRST THEORY.
It’s stupidly simple,
"Love” is a combination of hormones and pheromones that ensure you continue to propagate your genetic material. Everything, from who you have a crush on to the love a mother has for her child boils down to the simple purpose of every living thing: to reproduce.
“And what about you, Senku?”
He doesn’t spare a single glance to his classmate as he’s spoken to, focusing solely on the microscope slide he’s been preparing.
“Again, I don’t have even a millimeter of interest in your talk about crushes.”
He adjusts the focus.
Beneath the glass lens, millions of tiny creatures wriggle and swim.
“Killjoy.” His classmate pouts.
Turning back to his friends, he continues to chat loudly about which girls in class are the cutest, which would make good girlfriends, the works.
Yes, natural selection at work, how perfect for a biology class.
Senku wouldn’t say it’s his specialty. Physics and Chemistry tend to be just a little more straightforward, but it’s not like he could ignore a whole branch of science; After all, when building a rocket, it’s good to anticipate all the gruesome ways your body can fail you. Not only that, it's the one branch of science where attempting the same thing a hundred times and expecting a different result isn't insanity- it's having a decent sample size. The variation can be infuriating or exhilarating, depending on what you need.
“Well, not to brag, but I’m pretty sure it was the class prez that left me chocolates this Valentine’s,” The chatter goes on, and
Senku continues to analyze the microscopic ecosystem.
It’s just river water, so it’s usually nothing too exciting. He’s toyed around with microscopes enough times as a kid to know more or less what to expect.
“That’s totally bragging, though!” One responds.
Protozoan. Amoeba. Protozoan. Amoeba.
Oh look, this one’s in the middle of splitting up. Now there are two amoeba.
It's the miracle of life, so exhilarating, et cetera.
A laugh. “Oh come on, there’s no way it was her. I’m not believing it til’ you show us the letter!”
...
“It didn't come with a letter…”
“Then it could be from anyone!!!”
“Shut up!”
Senku cleans the tiny glass pane, washing away all those happy little amoeba and sterilizing whatever remained.
There was nothing all that exciting this time,
But you still check. Sometimes in the middle of all that useless mold you have one weird supermold that ends up being a miraculous drug. Sometimes you discover a single person that has a natural immunity to the doomsday virus. Sometimes a whale sings a song none of the other whales can hear.
Sometimes,
There's one weird monkey who insists on staring at river water,
Instead of having any interest in the biological imperative his fellow monkeys are all raving about.
The variation can be infuriating or exhilarating, depending on what you need.
...
The bell chimes.
Senku takes his time finishing up his notes and leisurely heads to the roof to meet up with Taiju and Yuzuriha. She usually brings a loaded lunchbox for them to share, but Senku recalls that today the cafeteria would have some special new sandwich Taiju wanted to get for the three of them; And he’s more than happy to let the big oaf deal with the resulting stampede of hungry highschoolers.
He leans on the railing, checks his phone. 12:35. Around 9 PM over in the states.
Senku considers checking his emails to distract himself, but there wouldn’t be nearly enough time to get through the walls of text waiting for him,
So he rests his eyes,
And his mind wanders.
It’s stupidly simple,
██████ ██ A combination of hormones and pheromones ████ ensure ███ ████████ ██ █████████ ████ ███████ █████████ ███████████ ████ ███ ███ ████ █ █████ ██ ██ ███ ████ █ ██████ ███ ███ ███ █████ █████ ████ ██ The ██████ purpose of every living thing = ██ Reproduce.
So either evolution's failed miserably in creating him, or there's more to it.
Though, devolving back to mitosis wouldn't be so bad, he figures. He could use having a second him to help around, and it would be ten billion percent less troublesome than dealing with romance. The stupid thought brings a smile to his face, but he's not going to singlehandedly reinvent single-cell reproductive strategies anytime soon, so—
Either something's wrong with him, or there’s more to this.
Taiju’s stupidly loud footsteps up the stairs snap Senku out of it. He’s avoided the topic until now, so there’s no reason to mull it over at this point.
“There he is! Senku!”
Taiju waves him over, sandwiches in hand. Beside him, Yuzuriha holds a small plastic bag of canned drinks for the three of them.
...
Senku stares down at his sandwich, the bread marked with the imprints of Taiju’s grip- Four perfectly spaced little divots.
“...I only noticed an hour later, and I had to frog pretty much the whole thing,” Yuzuriha laughs.
“Frog… it?” Taiju tilts his head.
“It means undoing your stitches! If you pull on the yarn, everything you did will slowly come apart, so you can fix any mistakes you made before.”
“Oh! Wait, why is it named that?” Taiju takes a sip from the can next to him.
“Well, it’s because…” Yuzuriha smiles sheepishly. “You ‘rip it, rip it’!”
They both laugh. Well, the three of them, if a sharp exhale counts. Taiju returns the can to its spot on the ground, only to realize he took Yuzuriha’s drink by mistake. In under a millisecond, his entire face turns two shades redder, and he stammers,
“I’m sorry, Yuzuriha! I’ll go buy you a new one!”
Yuzuriha seems almost equally flustered. “No no, it’s okay! I don’t mind!”
Taiju stands up. “But if you drink from that now, it’ll be—!!!”
Senku sighs. “You already drank from it, so it’s a bit too late to worry about indirect kisses now, big oaf. Sit down.”
“Still...!!!” Taiju’s face somehow goes redder. “I! I! I’ll go buy a new one after all!”
He runs off, and Yuzuriha half laughs, half sighs. Now that it’s just the two of them, an awkward silence overtakes the space usually filled by Taiju’s booming voice as they eat. Despite saying she doesn’t mind at all, Yuzuriha seems a bit hesitant to have any more sips of her drink. Senku wonders what’ll happen to it in a few minutes, if the two lovebirds keep acting like it’s radioactive. He might just swipe it for himself if it comes to that.
“Senku?”
“Huh?”
Yuzuriha hugs her knees, shooting him a slightly worried look. “You seem… a bit quieter than usual. Something on your mind?”
“Not really,” He lies, scratching his ear with his pinky.
“I see…” She doesn’t seem convinced. “No new ‘exhilarating’ ideas for the rocket?”
Oh, he wishes. Really, he should have his mind occupied by the rocket instead of mulling over the illogical, irrelevant feelings haunting his thoughts lately. What even is he feeling? He’s sure he’s not envying it, no, he could give a hundred different reasons why romantic relationships are more trouble than they’re worth. His complete lack of interest should be a blessing. No, it has been a blessing, so far.
“...Nah. I still have some annoying issues with the engine I need to iron out.”
“Hm…” Yuzuriha doesn’t probe any deeper. “Well, Taiju and I are all ears, you know. Even if neither of us know a thing about engines, maybe a fresh perspective would help.”
"..."
Senku stares off into the horizon, pondering for a few seconds before asking, “...Say, Yuzuriha. You like Taiju, don’t you?”
“Well—” She does a double take. Stammering, “Huh??? What’s this, all of a sudden?”
“Humor me for a bit.”
Yuzuriha fails to hold back a small laugh, covering her mouth with her hand. “You really took me by surprise there… You've never been one to talk about these kinds of things!”
“Yeah, don't get used to it. I'm just curious, is all.”
“Well…” She listens intently, anticipating Taiju’s footsteps to make sure he won't overhear them. “I do. But you look like you already knew that, so what were you curious about?”
“...How?”
Yuzuriha tilts her head, furrows her brows.
“You guys are childhood friends, don't say that…!”
“No, no, I don't mean it like that,” Senku sighs. “How do you know?”
“Oh! Well...” Her shoulders relax, and Yuzuriha looks up at the clouds lazily drifting overhead. Closing her eyes, she tries to find the right words to describe the indescribable. “I guess… there's a moment where it just clicks? And suddenly you start to see everything about them differently… something like that?”
She continues, “Like one moment you admire their qualities as just a friend, and the next, those same things make you feel like your chest is so full you can't breathe…”
“Scary,” Senku mutters.
“I'm opening up to you here, you know…!”
Hearing heavy footsteps up the stairs, they both fall silent. The doors to the roof open to a breathless Taiju, who no doubt ran to get back to them before the bell, a huge grin plastered on his face. Senku glances towards Yuzuriha, and behind the light reflected on her eyes, he could almost swear he saw the ‘click’. Deep, deep behind these lenses is this odd, illogical feeling he’s unable to grasp for himself.
It’s all the same, isn’t it? All the things he can’t reach for himself taunt him behind a pair of lenses.
Ugh. Gross. Scratch that.
He finishes the abandoned can, and stands back up. They have exactly two minutes before the bell rings, on the dot. He should get back to class. Passing Taiju by, he leaves the two with a curt “Alright, I’m heading back now,” and a wave.
...
It’s stupidly simple,
Everything, from who you have a crush on to the love a mother has for her child
ensures you continue to propagate your genetic material.
...
Senku tosses his bag onto the couch after fishing for his phone inside. It’s nearly 1 am overseas, but Byakuya still insists on calling him after school to check up on him. As he waits for his phone to buzz (He wouldn’t hear the end of it if he was the one to call first), he gets changed into something a little comfier and turns the TV on for some background noise.
Science isn’t some immutable truth. Theories are disproven all the time when they don’t measure up to objective reality. You just need to find evidence to the contrary.
…Luckily for him, it turns out it’s not too uncommon for animals that live in groups to have individuals that forgo reproducing altogether.
Many hive insects do, as the most obvious example. A worker bee couldn’t care less so long as the queen is alive and well. In mammals, too, many pack animals usually have a single breeding pair while the others support the group in other ways. Not even mentioning the whole can of worms that is adoption. Many animals will kill their own species' young for the sake of siring their own, and yet countless others will care for any baby, theirs or not. Sometimes, from other species entirely. You could blame that on maternal hormones, but it wouldn’t explain why a male with nothing to gain would do it.
His phone starts buzzing.
Click.
“You’re late, old man.”
A laugh. “Sorry, got caught up with some stuff!”
They chat about nothing important for a few minutes. Did he eat, what has he been up to, did he listen to that song he sent him, the works. Byakuya sure gets clingy when he’s away for too long, but Senku’s sure that if he doesn’t let him have this, some poor astronaut’ll have to hear him sulk and blabber about his cold, distant son the whole day.
“Alright, I’m hanging up.”
Click.
17:14. He has a few hours to study before dinner. He picks up the remote to turn the TV off, interrupting some tacky magic show halfway, and his reflection greets him on the pitch black screen. Before he heads back to his room, Senku stares into his own eyes.
From monkeys, then amoeba, and now bees? He could laugh at how stupidly bothered he’s been trying to explain something so inconsequential. Evolution’s working as intended. He’s not some special, one in a billion case. Simple as that. He can put off the romance talk for another billion years.
FIRST THEORY.
Discarded due to significant outliers.