"Ah, well, you can let that information go, Holmes," said Mycroft. "No one smokes anymore. It's been proven ruinous to one's health." I shot a look at Holmes, whom I had always warned of being a self-poisoner. "Besides, we've also learned much about the structure of the brain in the intervening years. Your fear that memorizing information related to fields such as literature, astronomy, and philosophy would force out other, more relevant data, is unfounded. The capacity for the human brain to store and retrieve information is almost infinite."
"It is?" said Holmes, clearly shocked.
"It is."
"And so you wish me to immerse myself in physics and astronomy and such all?"
"Yes," said Mycroft.
"To solve this paradox of Fermi?"
"Precisely!"
"But why me?"
"Because it is a puzzle, and you, my good fellow, are the greatest solver of puzzles this world has ever seen. It is now two hundred years after your time, and no one with a facility to rival yours has yet appeared."
Mycroft probably could not see it, but the tiny hint of pride on my longtime companion's face was plain to me. But then Holmes frowned. "It would take years to amass the knowledge I would need to address this problem."
"No, it will not." Mycroft waved his hand, and amidst the homely untidiness of Holmes's desk appeared a small sheet of glass standing vertically. Next to it lay a strange metal bowl. "We have made great strides in the technology of learning since your day. We can directly program new information into your brain." Mycroft walked over to the desk. "This glass panel is what we call a monitor. It is activated by the sound of your voice. Simply ask it questions, and it will display information on any topic you wish. If you find a topic that you think will be useful in your studies, simply place this helmet on your head" (he indicated the metal bowl), "say the words 'load topic,' and the information will be seamlessly integrated into the neural nets of your very own brain. It will at once seem as if you know, and have always known, all the details of that field of endeavor."
"Incredible!" said Holmes. "And from there?"
"From there, my dear Holmes, I hope that your powers of deduction will lead you to resolve the paradox-and reveal at last what has happened to the aliens!"
"Watson! Watson!"
I awoke with a start. Holmes had found this new ability to effortlessly absorb information irresistible and he had pressed on long into the night, but I had evidently fallen asleep in a chair. I perceived that Holmes had at last found a substitute for the sleeping fiend of his cocaine mania: with all of creation at his fingertips, he would never again feel that emptiness that so destroyed him between assignments.
"Eh?" I said. My throat was dry. I had evidently been sleeping with my mouth open. "What is it?"
"Watson, this physics is more fascinating than I had ever imagined. Listen to this, and see if you do not find it as compelling as any of the cases we have faced to date."
I rose from my chair and poured myself a little sherry-it was, after all, still night and not yet morning. "I am listening."
"Remember the locked and sealed room that figured so significantly in that terrible case of the Giant Rat of Sumatra?"
"How could I forget?" said I, a shiver traversing my spine. "If not for your keen shooting, my left leg would have ended up as gamy as my right."
"Quite," said Holmes. "Well, consider a different type of locked-room mystery, this one devised by an Austrian physicist named Erwin Schrödinger. Imagine a cat sealed in a box. The box is of such opaque material, and its walls are so well insulated, and the seal is so profound, that there is no way anyone can observe the cat once the box is closed."
"Hardly seems cricket," I said, "locking a poor cat in a box."
"Watson, your delicate sensibilities are laudable, but please, man, attend to my point. Imagine further that inside this box is a triggering device that has exactly a fifty-fifty chance of being set off, and that this aforementioned trigger is rigged up to a cylinder of poison gas. If the trigger is tripped, the gas is released, and the cat dies."
"Goodness!" said I. "How nefarious."
"Now, Watson, tell me this: without opening the box, can you say whether the cat is alive or dead?"
"Well, if I understand you correctly, it depends on whether the trigger was tripped."
"Precisely!"
"And so the cat is perhaps alive, and, yet again, perhaps it is dead."
"Ah, my friend, I knew you would not fail me: the blindingly obvious interpretation. But it is wrong, dear Watson, totally wrong."
"How do you mean?"
"I mean the cat is neither alive nor is it dead. It is a potential cat, an unresolved cat, a cat whose existence is nothing but a question of possibilities. It is neither alive nor dead, Watson-neither! Until some intelligent person opens the box and looks, the cat is unresolved. Only the act of looking forces a resolution of the possibilities. Once you crack the seal and peer within, the potential cat collapses into an actual cat. Its reality is a result of having been observed."
"That is worse gibberish than anything this namesake of your brother has spouted."
"No, it is not," said Holmes. "It is the way the world works. They have learned so much since our time, Watson-so very much! But as Alphonse Karr has observed, Plus ça change, plus c'est la même chose. Even in this esoteric field of advanced physics, it is the power of the qualified observer that is most important of all!"
I awoke again hearing Holmes crying out, "Mycroft! Mycroft!"
I had occasionally heard such shouts from him in the past, either when his iron constitution had failed him and he was feverish, or when under the influence of his accursed needle. But after a moment I realized he was not calling for his real brother but rather was shouting into the air to summon the Mycroft Holmes who was the twenty-first-century savant. Moments later, he was rewarded: the door to our rooms opened and in came the red-haired fellow.
"Hello, Sherlock," said Mycroft. "You wanted me?"
"Indeed I do," said Holmes. "I have absorbed much now on not just physics but also the technology by which you have re-created these rooms for me and the good Dr. Watson."
Mycroft nodded. "I've been keeping track of what you've been accessing. Surprising choices, I must say."
"So they might seem," said Holmes, "but my method is based on the pursuit of trifles. Tell me if I understand correctly that you reconstructed these rooms by scanning Watson's memories, then using, if I understand the terms, holography and micro-manipulated force fields to simulate the appearance and form of what he had seen."
"That's right."
"So your ability to reconstruct is not just limited to rebuilding these rooms of ours, but, rather, you could simulate anything either of us had ever seen."
"That's correct. In fact, I could even put you into a simulation of someone else's memories. Indeed, I thought perhaps you might like to see the Very Large Array of radio telescopes, where most of our listening for alien messages-"
"Yes, yes, I'm sure that's fascinating," said Holmes, dismissively. "But can you reconstruct the venue of what Watson so appropriately dubbed 'The Final Problem'?"
"You mean the Falls of Reichenbach?" Mycroft looked shocked. "My God, yes, but I should think that's the last thing you'd want to relive."
"Aptly said!" declared Holmes. "Can you do it?"