Just once, John would love to be anonymous again. 'John Watson' wasn't an uncommon name—so how did everyone know who he was? Even in the aftermath of the jump, it was always Sherlock's face in the papers—pale, intense, annoyed at being photographed—and John a blurry, ever-present shadow in the background.
Over and over again, John replayed Sherlock's actions. And every time he came up with the same deduction: Sherlock couldn't be dead. It was an impossibility. And John had learned: eliminate the impossible, and whatever remains is true. Since it was impossible for Sherlock Holmes, of all people, to kill himself, then he must be alive. If the lanky detective had taught John anything, it was that he couldn't always trust his own eyes. Sometimes, one had to trust the instincts of one's gut—or one's heart, whichever was stronger. And his heart said that Sherlock was alive.
How, John wasn't sure. Why Sherlock had inflicted this on him, he didn't know. But he had to believe that Sherlock was alive. In hiding, maybe, unable to return. John wondered and wished for something to tell him that he wasn't crazy or a victim of his own delusions, so he could forgive Sherlock the silence.
Not that forgiveness would stop John socking the idiot if he ever came back.