 What central theme of the story is revealed in the conclusion?
The evening was dark, it was unlikely that the other even saw the circle of steel that was the mouth of the shotgun barrel, now resting on the car's window ledge. And at that moment, the universe caved inward upon Joseph Marie Prantera. There was a falling through all space and through all time. And he came out of it as quickly and completely as he'd gone in. The other spoke precisely and slowly, the way a highly educated man speaks a language which he reads and writes fluently but has little occasion to practice vocally. It opened on his approach, the door sliding back into the wall in much the same manner as the room's door had opened for Reston-Farrell. He looked out, however, not on the lawns and walks of a sanitarium but upon a wide boulevard of what was obviously a populous city. The maternal linage was almost universally ignored." Whatever the something else was, a slot opened in the middle of the table and a glass, so clear of texture as to be all but invisible, was elevated. Briefly, we have transported you, I suppose one might say, from your own era to ours." Reston-Farrell said, "Suffice to say, you are now one hundred and seventy-three years after the last memory you have." The two men of the future said nothing more for long minutes while Joe Prantera's mind whirled its confusion. "That is why we brought you here, Mr. Prantera. And already he was beginning to long for the things he knew—for Jessie and Tony and the others, for his favorite bar, for the lasagne down at Papa Giovanni's. "In your day you were confronted with national and international, problems. "That we confront you now indicates that the problems of your day were solved. Our pedagogues are hard put to convince their students that such ever existed. More than a century and a half ago our society eliminated the reasons for international conflict. Depressions? Shortly after your own period, man awoke to the fact that he had achieved to the point where it was possible to produce an abundance for all with a minimum of toil. Overnight, for all practical purposes, the whole world was industrialized, automated. The second industrial revolution was accompanied by revolutionary changes in almost every field, certainly in every science. Your ancestors found, Mr. Prantera, that it is difficult for a man to be free so long as others are still enslaved. Today the democratic ethic has reached a pinnacle never dreamed of in your own era."
 If someone is willing to take a life, you cannot trust them to make moral decisions
 The more good you do for others, the more opportunity for them to criticize you  If someone is willing to take a life, you cannot trust them to make moral decisions  When cornered, threatened creatures will do anything to survive  The prosperity of a nation is more important than any individual life