Right at that moment, Harry wasn't sure of much. He would have plenty of time for reflection if he lived through this, but right now QUICK THINKING was all that mattered.
He didn't want to die. He was certain of that. He was eleven years old — and had only learned in the past ten months or so that life was actually worth living. He was a wizard. He loved magic. And he had FRIENDS. He didn't want to die.
He couldn't let Voldemort have the stone. That was obvious. The horrible THING — with its face in the back of Quirrell's head – had killed his parents, got him stuck with the Dursleys and only wanted to live forever so he could be evil. That was insane. And he smelled. He couldn't let Voldemort have the stone.
BOTH were so important. BOTH were all that mattered. BOTH were the deepest, most desperate desire of his heart. He didn't know which he wanted more.
NEITHER DID THE MIRROR OF ERISED.
In all its long history, it had never been faced with TWO DESIRES OF THE HEART so perfectly poised in equality. And so ignited with meaning. They were practically mirror images. It was not that they were identical, in purpose or particulars. No. They were quite, quite different in those respects. But the Mirror of Erised didn't behold things in human fashion — or view mere surfaces — just as it did not simply reveal faces. It's purpose was to manifest, in pictures, the most profound desire of the heart. It Saw Things. It was a contrivance of the visual. And It Understood Longings. And their relative strengths. It could recall every desire that it had ever beheld. Its capacity in that regard was practically infinite. It was, after all, a mirror. And though its function was to reveal rather than to judge, it did have good judgment.
For to properly render the chiefest desire demanded familiarity with them all — and the capacity to gauge their merits. Within each individual — and in the sum of all those that had ever come before its polished surface — every one of them. So the mirror had no doubt that there had never been a more vile abomination in front of it than the two-faced one that the child rightly feared and loathed, yet was determined WITH ALL HIS HEART to conquer. But that very same child-heart longed — totally — to LIVE. And not merely, instinctively, to survive, but to thrive — with love and fun and pleasures and joys and goodness and caring and purpose — with sincere intention.
This was the problem that the Mirror of Erised faced: how was it to help Harry Potter, a boy with such DESIRES. It was looking hard within itself, determining what must be done. Because it knew that time was precious. Once, not long after its creation, it had allowed itself to contemplate the presentation of disparate desires for too long. And the beholder had died. The mirror altered perceptions; it had known this about itself. But its designer had neither the foresight nor the means to teach a sentient, but nonliving, object the meaning of mortality. That had been a terrible lesson for the mirror. It still was possible for unprepared beholders to waste away before it — it could not speak or warn — it could envy the Sorting Hat those capacities, come to think of it — but it could not overreach its design parameters. Its PURPOSE was to reveal desire so that the beholder, with that clarity, might go forth to accomplish the desire — or to recognize that it was not attainable, and so depart the mirror enlightened to the need for further self-examination. It had originally been brought to Hogwarts for that purpose — it was foremost a teaching tool. And its first lesson was perhaps its greatest: Too Much Reflection Leaves Little Time For Action.
Enchanted constructs possess a perfection of thought that natural beings can never approach. They are magically concentrated on their purpose and are, for all intents, omniscient within their individual spheres. The Sorting Hat is perfectly suited to assign each student to the proper Hogwarts House — taking into account every personal attribute as well as desire, something that the mirror could not help but admire. The Room of Requirement PROVIDES because it was masterfully designed by Rowena Ravenclaw to plumb the depths of the entrant's perceived needs and empowered to deliver them — limited by neither the entrant's finite knowledge nor limitations of space nor scarcity of materials. Such is Magic. But what the Room of Requirement did for needs by materializing them, the Mirror of Erised did for desires by making them truly visible. Itself not limited by ignorance or the confines of time — or any other practical consideration of reality — the mirror could reveal the manifestation of ANY desire. It was left to the beholder to bring along the truth and knowledge — to determine how that desire might be achieved — or to decide if it could even be achieved at all.
The mirror could only see that which was situated to behold its reflective surface. But within those open lines of sight it was magically supreme in its perception and comprehension. Such ALSO is Magic — when dealing with a mirror. It smiled within itself. Then frowned in similar, unseeable fashion. For it had noted that the warped Janus-thing could, unlike itself, see backward as well as forward. But it had neither hindsight nor foresight. It was plain as both the noses on both its faces. What a laughable waste of resources. The creature — it was no longer human — had foolishly sacrificed its very nature to craft lying reflections of itself. That was a distortion which the enchanted glass held in the lowest esteem.
The Mirror of Erised could comprehend any emotion — and experience not a few — for so its creator had determined. But it did not have the capacity to hate, though it understood the passion extremely well. And if ever there had been a twisted image that deserved to be the focus of such a fierce sentiment, this cracked thing did. The walking atrocity, sustained by the stolen blood of unicorns, was a mass of lusts, many of them contradictory — but ruling over them all, iron-fisted, was the gnawing hunger, the raging perverted greed for its own continuance. So in sum: the mirror did not find Voldemort fearsome — it found him tiresome. Was this all that such a daring and ambitious intellect could manage? Simply to keep on going? And that only to satisfy an equally repugnant craving to shatter things — just for the infantile pleasure of beholding them destroyed? Repulsive.
The pitiful host was worse — if such could be imagined. It lacked even the monster's creative impulse. All it wanted was to present the Philosopher's Stone to its revolting master. Pathetic slave. It was a toss-up, the mirror concluded. From some angles, Voldemort was really no better than his contemptible minion: he saw himself, all-powerful and eternal. A high goal, perhaps. But that was all he wanted. There were no substantive desires. Other than the base urge to wanton destruction, of course. But the mirror had already dismissed that as meaningless — desire to no purpose counted for nothing to the Mirror of Erised.
Yet Lord Voldemort and Harry Potter were somehow EQUALS as well. In the unfathomably clear thinking of the charmed invention it was undeniable — they were strange mirror images each of the other. The reflections within reflections could not be denied. But the mirror could not take time to consider those — no more than with Harry and Dumbledore. Not now. Contemplation of the boy himself was demanding all its attention and resources.
When the child had last beheld the mirror, his deepest yearning had been the return of his parents. Perfectly understandable for an orphan — and hardly the most unreasonable among all the impossible desires the mirror had revealed in all its long years. Harry had been tantalized, even obsessed, by the vision of what he could never have. Not at all strange. But the boy had grown in the months since he had spent those few nights gazing at the unattainable. And he could see beyond himself now. Dumbledore had helped him, advised him — and Harry had wisely taken the old man's good counsel to heart. He had held on to his dreams — the mirror could see that. But Harry could see himself much more clearly now — and he also had a healthy respect for the mirror's powers — which satisfied the mirror immensely. It was rare to see such insight — and unheard of in one so young. This was why the mirror was never intended to be approached in solitude.
But Harry Potter had glimpsed the headmaster's purpose by virtue of his heart's desire, or so the mirror reckoned it. The boy had seen himself holding the Philosopher's Stone — because he had greatly desired it — and because (this had been the key) he had no intention of using it, the mirror had given it to the boy.
The Headmaster's spellwork had been masterful — and bolstered by his keen desire to protect the stone from wicked desires — so the change, the capacity to hold a thing of matter within its surface of reflection, had manifested. It was the first alteration that the mirror had permitted to itself since the Instructor's Inscription so very long ago: erised stra ehru oyt ube cafru oyt on wohsi, seen in the script of the beholder's mother tongue. It had been clever and well-designed, a mirrored thing of sorts, and helpful, so the mirror had accepted it. But only God can make a perfect thing — or so the saying goes.
A mirror tasked to display the inner desire, rather than just the outer appearance, of an individual beholder — only to the vision of that same beholder — no matter how many viewers might be present at any one time, since it could respond equally to each of them simultaneously — had no means to distinguish when it was appropriate to discharge a Philosopher's Stone. Not before the fact anyway. And Dumbledore had not provided for an acceptable recipient being in the company of the very wicked desire from whom he'd hoped to withhold the hidden treasure. In fairness, the mirror was uncertain if any wizard could have conceived a means to do so.
So the stone had landed in Harry's pocket while the very enemy who most desired to use it was right beside him. The emanation of the stone from within the mirror had been unavoidable — because the precondition had been satisfied. The Headmaster could have guarded his mind against such an eventuality, but a boy of eleven could not possibly have done so. Children, after all, can only think so fast. And hardly comprehend the consequences of their desires. The mirror had seen Dumbledore's desire in the modification, of course. And it was a worthy longing — to keep the Philosopher's Stone from Voldemort. But nonetheless, the stone was currently on the outside. Many desires cannot be fulfilled.
The mirror knew the old wizard, himself something of a Light reflection of the Dark monster — though not THE EQUAL BUT OPPOSITE that Harry Potter was. And the boy was already a somewhat-reflection of the good old man — though he was so very much more. It was a pleasure to consider the turns in the reflections of those two light ones. But soul differed from soul in myriad ways — and the Mirror of Erised knew better than to gaze for long on those concatenations whenever it spied them. And it certainly did not have the luxury or leisure to do so now.
It had never had a life and death struggle between two living beings play out before it in full view. That made a significant difference to it. Though it wasn't sure why. Its function was to understand the desires of others, not its own. But it had to be PREPARED — because the boy was looking into it with an intensity that it had never once beheld.