Getting the paper was not only physical possible, but it was easy. Tom watches it scutter along the ledge, thinking it might fall off.
...and then he saw that the paper was caught firmly between a projection of the convoluted corner ornament and the ledge.
To simply go out and get his paper was an easy task--he could be back here with it in less than two minutes--and he knew he wasn't deceiving himself.
He doesn't have to worry about the paper blowing away before he can reach it. That is what makes it so enticing. It could be stuck out there for days, and he would not be able to stop thinking about it and looking at it. The sheet is only about five yards away from his window. The only problem is an internal one. He can't lose his nerve, and he doesn't dare to look down. The sight of the street from the eleventh story could make him succumb to vertigo. So he mustn't let his imagination run away with him, and he must keep his eyes fixed on the brick wall right in front of his nose.
Tom manages to get to the paper without too much trouble, although the ledge isn't quite as wide as he thought it would be. He is forced to walk sideways on the balls of his feet. This puts his whole body in an awkward position and threatens to cause cramps in both his legs if he stays that way too long.
The situation does not become critical until he actually gets to where the yellow sheet of paper is stuck in the corner. He tries to reach for it without looking down. This, of course, forces him to bend his knees and extend his hips farther out over the ledge. With the top of his head pressed against the bricks, he lowers his shoulder and gets a hold on the paper with his fingertips. But--
At that same instant he saw, between his legs and far below, Lexington Avenue stretched out for miles ahead....He saw, in that instant, the Loew's theater sign, blocks ahead past Fiftieth Street; the miles of traffic signals, all green now; the lights of cars and street lamps; countless neon signs; and the moving black dots of people. And a violent instantaneous explosion of absolute terror roared through him.
After than he loses his nerve. What seemed so simple now seems impossible. He is frozen in one awkward and painful position. He doesn't dare to move his legs. If his wife could see him now she would think he was utterly insane. And he begins to wonder about his sanity himself. If he is not sane, how can he ever make it back to his apartment window?
Getting the paper was physically possible. He has proved that because he actually has physical possession of the paper. It will become one of the "contents of the dead man's pocket." The whole conflict in this story is internal. It is a conflict of man against himself. Tom manages to win that conflict and creep back to his apartment window, break the glass, and crawl back inside. Ironically, it would seem that the story is about a physical feat, when in reality it is about a psychological victory.