Occam's Razor

Phoenix Song, Chapter Twenty-Three : Occam's Razor

DISCLAIMER : The characters and many of the situations described in this story are the property of the incomparable J.K. Rowling. I make no money from this story, which exists as a work of tribute. Dialogue quoted from the original HP books is marked with an asterisk.

Without the help of my betas, LAxo and WriterMerrin, reading this story would be a far-less-pleasant experience for everyone concerned. They have my eternal gratitude.

Hermione had been delighted that morning when Harry had agreed to use his Felix Felicis. A little bit of luck, she thought, was just what he needed to convince Slughorn to give him the memory about Horcruxes. From the moment he swallowed the golden liquid, however, Hermione had doubts. Instead of heading for Slughorn's office, Harry was suddenly determined to visit Hagrid and preside over Aragog's funeral...and nothing that she or Ron said convinced him otherwise. As Harry disappeared under his cloak and then trundled down the stairs from the boys' dormitory, Hermione glanced at Ron and pulled a comical face of despair.

"Come on," muttered Ron, grimacing back, "Let's go after him."

At the bottom of the staircase, however, any thought of catching Harry before he left the common room was lost.

"What were you doing up there with her?"* shrieked Lavender.

"What are you..." Ron spluttered to a halt when his brain caught up with his mouth and the realisation hit home that he couldn't well invoke Harry as his defence. "Hermione is my friend, Lav..."

His second effort at coherent speech was cut short by Lavender re-entering the fray.

"Yeah right, Ronald Weasley! Friends don't get jealous and not speak to you just because you've got a girlfriend who truly appreciates you! Friends don't disappear up into the boys' dorm with you; they hang out in the common room where everyone can see what's going on! Friends don't look so goddamn smug when your girlfriend is yelling at you!"

Time to leave, thought Hermione, her sense of self-preservation winning over the urge to stay and scream back at Lavender.

"Right then, Ron," she said brightly, "I'm off to the library. Come along later if you want."

As far as Lavender was concerned, Ron's desperate attempt to catch hold of Hermione's arm was quite possibly the nail in the coffin. Hermione heard her shrieks intensify still further as she slipped out into the hallway. Well, she thought to herself, every bit as smug as Lavender had suggested, that's a bit of luck!

Ron joined her after about twenty minutes, looking harassed but mostly relieved. "We broke up," he explained lamely, in response to her inquisitive eyebrow. "I don't suppose you'd look over my Transfiguration essay, would you?"

Hermione sighed melodramatically, but accepted the tentatively proffered essay with a grin. Things were looking up.

The next day, Hermione ran into Ginny on the staircase leading up to the girls' dormitories.

"Hey, Hermione," said Ginny with a glum smile.

"Hey, what's the matter?" Hermione stopped, looking up at the younger girl who stood several steps above her.

"Oh, nothing. Just Dean being a total prat about breaking up yesterday."

"Breaking up is hard to do?" joked Hermione, but the Muggle reference was wasted on Ginny.

"I guess you could say that."

"If it's any consolation," offered Hermione, thinking back to Harry's carefully nonchalant expression earlier that morning when he had heard the news, "I think your relationship with Dean might have served its purpose."

Ginny brightened immediately. "For real?" she asked, her eyes shining with a sudden (and slightly scary) intensity.

"For real."

"Hey, thanks, Hermione!" Ginny flipped her hair over her shoulder and practically danced past Hermione on her way down to the common room.

Hermione smiled to herself and continued upstairs; if only all of her problems were so easily solved. To her great relief, neither Lavender nor Parvati was in the room, and she kicked off her shoes and crawled into bed, closing the curtains carefully around her. Hermione had about an hour and a half before dinner and some serious thinking to do. Drawing her wand, she cast several of the protective wards she'd learnt from Snape: That should deal nicely with interruptions.

That morning during Charms, Harry had related the full story of his adventures last night: from Aragog's funeral and the process of getting the memory from Slughorn, through viewing the memory and the horrific details of what a Horcrux was, to Dumbledore's promise to take Harry along on the next Horcrux-finding mission. Horcruxes. Hermione shivered at the thought of splitting a soul once, let alone seven times...No, she correct herself, logic reasserting itself over horror, Six times. Six splits equals seven pieces. Two of which were already destroyed. She listed off the remaining Horcruxes: The locket, the cup, something of Ravenclaw or Gryffindor's, and quite possibly the snake.

And how, she wondered, do the Horcruxes relate to the seemingly devastating plan that will happen this year? And what do they have to do, if anything, with the information Professor Snape is supposed to give me? She wrapped her arms around her knees and drew them tightly towards her chest. Probably nothing, she decided. I was always going to learn about the Horcruxes from Harry; the information from Professor Snape has to be about something else.

Hermione sighed. She couldn't keep everything straight in her mind. Leaning forward, she snagged the strap of her satchel and pulled it along the coverlet towards her. Rummaging inside, she found a pencil and a piece of parchment. It was time to make a list.

Plan 1 – Kill Voldemort

NB : While anyone, theoretically, can destroy the Horcruxes, secrecy is crucial (If V finds out, he'll just make more); therefore in practice, this comes down to Dumbledore, Harry, Ron or Hermione.

Hermione felt a bit silly putting her own name down as a potential Horcrux hunter, but she liked to be thorough. Plan 1 was straightforward enough. Plan 2 was far more difficult to summarize because Hermione wasn't clear on what the plan actually was. She got as far as:

Plan 2 – ?

Progress : ?

before deciding she needed to take a different tack, perhaps writing down everything that she did know and who was involved at what stage. She started over with a new piece of parchment.

Plan with seemingly devastating consequences.

People who don't : McGonagall, Vector, Hermione, everybody else (inc. Harry).

By now Hermione was stretched on her front, legs kicking in the air and one curl wound around the index finger of her left hand. She left a gap and continued writing lower down the paper.

Draco Malfoy. Death Eater (?) trying to kill someone at Hogwarts, doesn't care who he hurts in the process (Katie Bell, Ron)

Someone else entirely (?)

Hermione hesitated, chewing on her bottom lip, then added:

NB : Snape promised to help and/or protect Draco (Unbreakable Vow...Narcissa Malfoy).

She paused again, before finishing the thought:

Therefore Dumbledore knows/Snape maintaining cover.

Hermione sighed and turned her eye back to the list of possible targets. It was laughable to think of Draco killing Dumbledore, Dumbledore is practically invinci...the memory of his blackened arm cut that thought short. Malfoy couldn't, but . . .

She swallowed. The words on the page before her seemed to swim in and out of focus. She was going to be ill.

Hermione slid from the bed and clumsily pushed her way through the curtains, stumbling into the bathroom in a daze. It was a close call, but she managed not to lose her lunch. In an attempt to restore her equilibrium, she forced herself to take several deep breaths and splashed her face liberally with cold water. Okay, Granger, she told herself. Pull yourself together.

As she re-opened the bathroom door, she froze, as did Parvati and Lavender. All three girls regarded each other warily.

"Hi, Hermione," they chorused, their voices falsely sweet.

"Hi." Her own response was terse.

"Um." Parvati's eyes skidded away as she spoke. "What happened to your bed?"

Hermione looked around in surprise to the place where her bed should have been, but there was nothing there. It took a couple of seconds for her brain to catch up with her gaping mouth, but eventually she realised that the wards she had cast were so strong that the bed itself had been concealed from view. She smothered an urge to giggle hysterically.

"Just practicing for my Charms extra-credit project," she lied, giving a tight smile to Parvati and Lavender in turn. Then she strode across the room without hesitation. As she crossed the wards, she felt the tingle of them on her skin, and simultaneously, her bed reappeared. She turned. From the look on Lavender and Parvati's face, she had just disappeared. She tried not to feel smug, but failed.

The feeling didn't last long. Back behind the curtains of her bed, she was obliged to confront her list once more...and the implications of the information it contained. She forced herself to think about it calmly. Don't rule out anything, yet, she reminded herself. Everything is not necessarily what it seems.

She picked up her pencil firmly. This is merely a logical exercise. She said it out loud to make it seem more real. "This is merely a logical exercise."

Assumption : Malfoy is trying to kill Dumbledore.

Therefore : When Malfoy fails, Snape will die (Unbreakable Vow).

Hermione didn't bother to consider the possibility that Malfoy might succeed. Instinctively, she felt that the first of these options was best described as a "plan with seemingly devastating consequences," but she couldn't yet explain why it might be more likely.

If Snape lives, she wrote next, Dumbledore dies. If Dumbledore lives, Snape dies.

Spy or Mastermind?

Hermione stared at the words before her for so long that they no longer seemed to make sense, no longer seemed anything but black scribbles on white parchment. Then she wrote three more words, punctuating them with a question mark:

Dumbledore already dying?

In the end, Hermione went down to dinner. There wasn't much else she could do. The boys greeted her late arrival with some relief.

"Wunnered where you'er," commented Ron around a mouthful of mashed potatoes.

"Studying," she replied distractedly, serving herself a generous pile of the nearest green vegetable (green beans, in this case).

The Great Hall was not the place for personal conversations of any kind, and with Ron and Harry already deeply engaged in a conversation about whether or not the Apparation teacher, Wilkie Twycross, was any relation to a professional Quidditch player with the same surname, Hermione was able to coast through the meal without paying much attention to her surroundings. Instead, she obsessed over the realisations and suppositions of the past few hours. If Snape kills Dumbledore, he'll be an outcast; he'll have to go on the run; his life will be in terrible danger. On the other hand, it would cement his position within Voldemort's circle; it would put his Death Eater status above suspicion.

On the assumption that it was the safest of all possible locations...wards or no wards...Hermione had tucked her notes into her bra, and every time she moved during dinner, she felt the corner scratch against the bumpy surface of her scar. Only briefly had she considered the possibility that Snape was a traitor. Perhaps Dumbledore is wrong to trust Snape? Harry certainly thinks so. But Dumbledore's own words echoed in her mind, "I would trust him with my life." Dumbledore was too clever...and too manipulative...to use such a phrase lightly.

Long before the meal was over, Hermione knew that she had to speak with Professor Snape. Because of a scheduling conflict, the Gryffindor Quidditch team was only training once this week, on Thursday, but Hermione didn't think she could wait another 48 hours to broach the topic. It had to be tonight.

When Snape rose from the dinner table, Hermione rose too. The dessert had only just arrived, and Harry looked up at her in surprise.

"Where are you off to?" he asked.

"The library, sorry, I've loads to do." The most generic lies were usually the best.

"'Mione," said Ron reproachfully, "You've barely eaten anything! You should stay another few minutes and eat some treacle tart."

His concern snagged at her heart. Her love for both boys swept over her with a rush, quickly followed by a stab of panic. She didn't have time for this.

"Not everyone has to consume their weight in dinner just to make it through the evening, Ronald Weasley. I'll see you later." Hermione rushed away, making it to the Entrance Hall just in time to see Snape disappear down the stairs leading to the dungeons. She hurried after him.

Snape paused about halfway down the corridor to speak with a group of second-year Slytherins. One boy, safely positioned out of Snape's line of sight, noticed Hermione as she came into view and pulled a face. His rudeness struck Hermione with a jolt of inspiration. Pulling her wand from her pocket, she pointed it at the insolent child. His face fell immediately, and he called out in fright, ducking behind his closest friend. At the commotion, Snape turned, only to find himself face to face with Hermione, her wand levelled in anger.

"What is the meaning of this, Miss Granger?" he snarled as he stepped towards her, fury emphasising the harsh lines of his face.

"Pluralitas non est ponenda sine necessitate," she replied. Hermione was breathing heavily, willing him to understand her.

His eyes narrowed. "Detention," he barked. "Now."

She turned instantly and headed towards his office. Snape stalked behind her, an ominous, angry presence. The Slytherins scattered as they passed, their shocked whispers a syncopated staccato to the ringing sound of Snape's boot heels against the stone floor.

He slammed the door behind her as soon as they entered his office.

"You'd better have a good explanation for your behaviour, Granger, or you'll be scrubbing cauldrons without magic for the next four hours."

"I needed to speak with you, sir."

"Sit," he ordered, striding around his desk in order to take his own seat.

Ensconced in her regular chair with Snape scowling at her across the table, Hermione was at a loss as to where to begin. She rubbed one hand up against her scar, the crinkle of the parchment under her fingers contributed to her sense of urgency, but still she didn't know exactly what to say.

Eventually, Snape sighed with irritation. "Had I known you harboured such a desire to stare at me, Granger, I would have sent you to the Hospital Wing, not given you detention. Do you, or do you not, have something to say that is worth disrupting my plans for this evening?"

"I . . . I do, sir." Hermione took a deep breath. "Is it true," she asked, "that Professor Dumbledore is dying?"

Snape gave her a long look. "Where did you get that idea, Granger?"

"Observation. You didn't answer the question."

"No, I didn't."

This was getting her nowhere. "He makes no attempt to hide his blackened hand, and it's getting worse. There are certain curses . . ." she trailed off.

Snape's mouth hardened. It was as if a shutter came down over his face, more rigid and terrifying than the teacher she normally interacted with. "Very astute, Miss Granger. But I assure you, the curse will be insufficient to kill Albus Dumbledore."

Hermione fiddled nervously with the edge of the desk. Almost in spite of herself, she was impressed by his ability to walk sideways through the truth. She cleared her throat; the time for Gryffindor bluntness had arrived. "I imagine that Draco Malfoy will prove similarly insufficient."

Snape sat perfectly still. When he spoke, his voice was completely level and almost conversational in its politeness. "What are you implying, Miss Granger?"

Hermione gripped her hands into fists, the nails digging painfully into her palms. "I'm implying, sir, that you and Professor Dumbledore have concocted a plan whereby you will kill Dumbledore in Malfoy's place. The other Death Eaters would have no reason to doubt your loyalty then."

Snape raised one eyebrow. "Indeed?" he queried in a tone of polite disbelief. "And what reason, might I ask, would Draco have for attempting to kill the headmaster in the first place?"

"Because, sir, he's a Death Eater, or trying to become one in order to take his father's place." Hermione's voice shook a little. It was unnerving facing this cool, disinterested Snape when she'd expected him to rant and rave.

"An underage wizard? Tasked to kill the most powerful warlock alive today? It doesn't seem very likely." He shifted slightly in his chair, and his dark hair swung forward to frame his face. "How did you arrive at such a far-fetched conclusion, Miss Granger?"

Hermione hesitated only a second, then summoned the parchment from inside her shirt. She carefully separated the two sheets, folded up the one containing the notes on Harry's Horcrux hunt and tucked it safely into her pocket. The other, she spread flat. "Occam's razor," she replied, handing it to Snape.

He read the paper through, twice, before speaking. "As a logical exercise, Miss Granger, this work is significantly flawed." He let the parchment drop onto the table between them.

She wished he would stop calling her Miss Granger and revert to his ordinary self. "What error have I made, sir?"

"The solution you propose is not the most logical." He picked up his quill and added a line of text between two of hers, then slid the parchment over towards her. Now, near the bottom of the page it read:

Assumption : Malfoy is trying to kill Dumbledore.

Conclusion : Snape is loyal to the Dark Lord and always has been.

Hermione's heart was thudding loudly. "Too simplistic, sir," she replied. "It doesn't adequately account for all the information. I know, for example, that you're loyal to Dumbledore."

"You have no proof of that." His voice was harsh.

Hermione's chin rose slightly, and there was a fierce light in her eyes. "I don't need proof of that, sir," she said, as clearly and confidently as she could.

Snape snarled, a guttural, growling noise that came from deep in his throat. "Then you're a fool. Who do you think would believe you, Granger, were I actually to murder the headmaster as you have suggested?"

At his use of her name alone, one of the hard knots in her stomach loosened. "No-one, probably." She hesitated for a second, biting down on her lower lip. "I imagine you're going to have a fairly hard time of it, sir." Something flickered across his face, too quickly for Hermione to be sure of what she saw. "I thought," she continued, "that this might be the information I needed to get from you. With Dumbledore dead, Harry might well lose it completely. Who knows what the Ministry will do with the school? Harry has . . . a job to do, we might have to go on the run. It's my job to keep Harry alive. I need to prepare."

"Granger..." groaned Snape. "You're babbling."

"Sorry, sir."

He ran one hand roughly down his face. He looked . . . fragile. Hermione was swept with a sense of injustice. How could Dumbledore ask this of him? It's inhuman. She bit down on her lower lip, restraining the urge to hold forth on how unfair everything was. Don't babble, Granger, she reminded herself.

For a long moment, neither Hermione nor Snape spoke. Eventually, he picked up the parchment covered in notes and read it once again. "How did you know I made an Unbreakable Vow?" he asked, only a tinge of irritation in his voice.

"Um, I'm afraid I can't tell you, sir."

"Can't, or won't?" He sneered. "Let me guess, it involves a certain miscreant and his invisibility cloak?"

Hermione shrugged and held her tongue. Snape sighed and tossed the paper back on his desk. "Make sure you dispose of this wisely," he recommended, gesturing towards the parchment. Obediently, Hermione levitated it and sent it soaring into the fire. For a second, they both watched it burn.

"How many others do you think might come to the same conclusion?" he asked.

"No-one, sir. No-one has all of the same information, for one. And," she hesitated.

"And?"

"And you've been too successful at walking the line, sir. Most people will readily believe the worst of you."

Snape opened his mouth as if to speak and then shut it abruptly. For an instant Hermione thought he might weep, but he pulled himself together very quickly.

"Very well, Granger," he said. "Come back on Thursday; we'll plan for your life on the run."

"Sir?"

"You are dismissed, Granger. Leave now, or you really will have detention."

Reluctantly, Hermione stood up. Snape looked terrible, and she was loath to leave. She wanted...unthinkably...to hug him, she wanted to rail against the difficulty of his position, she wanted to reassure him, to tell him that it was euthanasia not murder; but she couldn't. Though he had neither explicitly confirmed nor denied her theory, and though he left her with no doubt as to its veracity, they certainly weren't having a conversation about it. She walked to the door, hesitating with her hand on the doorknob.

"Now, Granger," he snarled before she looked round.

"Good night, sir," she replied hurriedly as she stepped out into the corridor.

Hermione stood staring at Snape's closed door until she got worried that he, or some other Slytherin, would find her there. She couldn't, though, return to the common room. Her head was buzzing, and she wasn't capable of maintaining a normal conversation. Instead, she turned her feet towards Vector's office. This was the kind of nervous energy that only Arithmantic calculations had any hope of dissipating. And Hermione had a lot of new information to code into the matrix.

A / N : Occam's razor is a logical theorem that posits the simplest explanation that accounts for all phenomena as the most probable outcome. The statement of the theorem in Latin, Pluralitas non est ponenda sine necessitate, translates literally as "plurality should not be posited without necessity." (I lifted the translation from wikipedia!)